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reaction to their illness or even may have culty in asking sensitive questions lies with our own biases, contributed to their illness. The Paramedic should be con- embarrassment, or perceptions with these topics. Some scious of nonverbal clues to the patient’s anxiety and, when patients will readily answer these questions when asked in a he senses anxiety, encourage the patient to talk about his or professional manner. Questioning a patient about these top- her feelings. ics becomes easier with experience. It is often helpful for each individual Paramedic to observe more seasoned provid- Reassurance ers obtaining this information and then develop an effective Providing reassurance to patients can be both benefi cial and method which works. harmful depending on the way it is provided. In an emer- gency situation, many patients worry not only about their Silence condition, but also how it affects others they care for or love. For many of us, silence is uncomfortable. Nonetheless, it By providing reassurance, the Paramedic can help calm the must be remembered that silence has many uses and possible patient down, allowing him to make appropriate medical meanings. Patients may use silence to collect their thoughts decisions or be more cooperative with the assessment and or remember details about their concerns. Silence may be the treatment. Conversely, reassurance can provide false hope if result of insensitivity by the Paramedic in asking questions, provided improperly. Statements like, “Everything will be or the patient may be taking some time to decide whether or OK” and “You have nothing to worry about” are detrimen- not to trust the Paramedic. tal when patient receive the news that they have developed Whenever confronted with unexpected silence, the Para- a severe condition. It is more appropriate to acknowledge medic should be alert for nonverbal clues of distress and try that there are factors that are of concern, but state that it is to determine if anything in his interview technique might be better to focus on getting well fi rst and take it a step at a responsible for them. time. Reassurance that the patient is in good hands or going to see a good physician can also help the Paramedic provide Overly Talkative Patients positive reassurance to the patient without creating a false It is easy to become impatient with an overly talkative patient expectation. when time is of the essence. A few techniques may be helpful in this diffi cult situation. Anger and Hostility Although not ideal, the Paramedic may have to lower It is not unusual for patients to exhibit anger toward health- expectations and accept a less comprehensive history. It care personnel for a variety of reasons, including feeling may be helpful for the Paramedic to allow the patient free unwell, suffering anxiety, or developing a feeling they have reign for the fi rst few minutes and then directly question the lost control over their lives. Paramedics should not take this patient about the most important details. If necessary, he behavior as anger against them personally. They can attempt should interrupt the patient as gently as possible and sum- to defuse the patient’s anger by identifying that, although they marize the history as succinctly as possible. Phrases such as understand he is angry, you are there to help him. Paramed- “I’d like to hear more about the chest pain you had before ics should always remember that their safety and that of their you called us” may help to refocus the patient on the chief crew are paramount, and thus they should retreat from any concern. situation which becomes dangerous.23,24 History Taking 249 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. The Intoxicated Patient patient’s concerns and instead attempt to focus in on a single chief concern. Acutely intoxicated patients who are belligerent, angry, or uncooperative can be some of the most diffi cult patients to Limited Intelligence interview. Paramedics should use a calm, direct voice and simple directions to encourage the patient to allow himself to Most patients with even moderately limited intelligence can be assessed and treated. The Paramedic should try to avoid usually give adequate histories. When patients suffer from talking to the patient in a confi ned area, as the patient may severe mental impairment, however, most of the history will feel trapped and react with hostility. Intoxicated patients can have to be derived from other sources, such as family, friends, be unpredictable; as a result, sudden violence is always a pos- or medical charts. The Paramedic should use simple language sibility.25 Paramedics should always have an escape route when interviewing the patient and listen closely as the patient planned and retreat from any situation which cannot be easily describes tests or other elements of his medical history. de- escalated.26 Patients who appear clinically intoxicated do However, the Paramedic should be careful about mak- not have the capacity to refuse care. Signs of clinical intoxica- ing assumptions about the patient’s level of functioning. The tion include slurred speech, disorganized thinking, inappropri- best technique, just as with any other patient, is to establish a ate responses to your questions, combativeness, and staggering relationship fi rst with the patient and then, if necessary, seek gait. A Paramedic may need to enlist the aid of local law other sources for history. enforcement to assist in bringing the patient to the emergency department for evaluation if the patient refuses to go. Language Barriers When confronted with a patient–provider language barrier, Crying the Paramedic should make every effort to obtain a transla- Crying is an important clue to emotions.27–29 The Paramedic tor. The best translator is a neutral, objective observer who should be supportive and wait for the patient to recover. Quiet is fl uent in both languages. Using a family member often acceptance or a supportive comment may assist the patient in leads to distorted meanings and may present a confi dentiality problem.31,32 composing herself and continuing the interview. Handing the The Paramedic should look at the patient when patient tissues is a gesture that is always appreciated. talking, and not the translator. Also, he should ensure that the translator asks the patient the question and is not just answer- Depression ing the question for the patient. Depression is a common medical problem and can have mul- tiple manifestations. The Paramedic should always maintain a high index of suspicion for depression in patients complain- Cultural / Regional differences ing of multiple, vague symptoms. If the patient is depressed, one should be concerned for the possibility of self-harm and question the patient directly about suicidal thoughts.30 Any In many regions and cultures, it is disrespectful patient with the potential for self-harm must be transported to for children to question their elders, especially in an emergency department for further evaluation. personal matters. Usually, however, the children Seductive Patients are fl uent in the two languages. If it is necessary Occasionally a provider may feel attracted to a patient. If to use children as translators, one should ask as the Paramedic becomes aware of such feelings, one should few questions as possible and alert the staff at the realize that these thoughts are normal responses. However, hospital so that a more thorough and accurate history one must prevent these feelings from affecting her profes- can be obtained. sional interaction with the patient. Some patients may make sexual advances toward the Paramedic. Paramedics need to make clear to these patients that the relationship with them is purely professional. It is unethical, and in some states illegal, Hearing Impaired Patients for a Paramedic to have a personal and/or sexual relationship Patients with hearing impairments may present as many issues with a patient who is under his or her care. as those with language barriers. The Paramedic should look at the patient directly while talking and speak slowly. Often Confusing Behaviors or Histories the patient is able to read lips well enough to answer the Para- Occasionally, despite best efforts, the patient’s history does medic’s questions. He should avoid shouting or raising his not appear to make sense and the Paramedic may feel baffl ed voice unless the patient indicates it helps her hear the ques- or confused. While many of these situations involve an emo- tions. If the patient has a “good ear,” the Paramedic should tional component, the Paramedic should avoid dismissing the make a point of speaking toward that ear. Communication 250 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. through written notes, although time-consuming, may be the Paramedic should avoid making any sudden movements that only solution to obtaining an adequate history. may increase the patient’s anxiety in what is likely already a stressful situation. Vision Impaired Patients When talking to a patient with limited vision, the Paramedic Family and Friends should make sure to identify herself, alert the patient to her Sometimes the Paramedic may need to elicit the history location, and explain what is being done. She should remem- from family, friends, or other bystanders.33 Whenever pos- ber to always respond vocally to the patient and avoid rais- sible, the Paramedic should get the patient’s permission to ing her voice while speaking. The Paramedic may need to discuss the condition with the other person. If the Para- explain procedures and actions in more detail than is needed medic cannot get permission, then he should remember that for patients with normal vision. If walking with a patient with all medical information derived from the patient interview vision impairment, the patient should grasp the Paramedic’s or exam must be held confi dential and not shared with the arm rather than the Paramedic grasping his or hers. The third party.34–37 History Taking 251 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. The novice Paramedic must master the skill of history taking in order to be effective at providing care to the vast array of patients encountered during one’s career. With practice and by observing other experienced healthcare providers obtain a history from a patient, the novice Paramedic will soon develop and refi ne her skill. Key Points: • History taking is the medical questioning of a • The chief concern is the main reason EMS patient for purposes of ascertaining the disorder, was activated and should be expressed and syndrome, or condition affecting the patient that documented in the patient’s own words using resulted in the activation of EMS. quotation marks. • The Paramedic must be aware of the messages • Several methods can be used to assess a patient’s transmitted by words and actions and have a pain, from a simple “mild, moderate, severe” scale professional appearance and calm demeanor. to a 0 to 10 or faces scale. • The Paramedic should formally and respectfully • The mnemonic device OPQRST AS/PN can be used introduce himself and explain his job function. for any concern of pain. The mnemonic AEIOU-TIPS • is used for altered mental status. The Paramedic should inquire as to the patient’s preferred manner of address. • The mnemonic HAPI-SOCS is used for shortness of • breath. An open-ended question allows the patient to answer in his or her own words rather than give a • The mnemonic IN SAD CAGES is used for psychiatric |
simple answer of yes or no. issues/depression. • Interviewing techniques which assist the • The mnemonic SAMPLE is used for gathering Paramedic in developing questions and promote past history. Ask additional questions for dialogue include facilitation, refl ection, clarifi cation. clarifi cation, interpretation, and direct questioning. • The Paramedic should be conscious of nonverbal • A comprehensive medical history is taken to clues to anxiety or anger. discover as much information as possible about a patient’s concerns, interpersonal relationships, and • When communicating with an acutely intoxicated medical history. However, it is often not used in patient, the Paramedic should use a calm direct emergent situations due to the extensive amount of voice, and give simple directions to encourage data it collects and time required. patient access to evaluation and treatment. • A focused history can be conducted by the • Strong emotions exhibited by the patient during an Paramedic to concentrate on the chief concern, interview may require the Paramedic to assist the history of present illness, signifi cant past medical patient through quiet acceptance or a supportive history, and pertinent current health status. comment. The mnemonic SAMPLE is used to remember the • The Paramedic should always keep the patient different historical components of a focused relationship professional. history. 252 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. • The Paramedic should use simple language, listen • The Paramedic should explain who he is, where he closely, and not make assumptions about a patient’s is, and what he will be doing in a clear, normal tone level of function when interviewing patients with of voice for the vision impaired patient. mental impairments. • All medical information derived from the patient • When confronted with a patient––provider language interview or exam must be held confi dential and not barrier, the Paramedic should make every effort to shared with a third party. obtain a translator. Review Questions: 1. How can the Paramedic set the stage for an responsive, and hypoxemic on room air. You effective patient interview? attempt to obtain a history from the patient 2. List the interviewing techniques that can assist without success due to his mental status. What the Paramedic in developing questions and other sources of information can be helpful promote dialogue with a patient. to you and the emergency department? What 3. A male patient makes sexually suggestive questions are important to ask? statements to a female Paramedic. How should 7. If confronted with an overly talkative patient, the Paramedic handle this patient? what can the Paramedic do to effectively gather 4. List the components of the focused history a medical history? and the information acquired by asking those 8. Using a translator, a Paramedic is speaking with questions. a patient with a language barrier. What should 5. Why is it critical for the Paramedic to ask about he be conscious of when asking and receiving tobacco, alcohol, and other recreational drugs? responses to questions? How might the Paramedic do so? 6. You are called to a nursing home to transport an elderly male patient who is febrile, barely Case Study Questions: Please refer to the Case Study at the beginning of the • Altered mental status chapter and answer the questions below. • Psychiatric disorders or depression 1. What mnemonic is best for 2. What is the value of a mnemonic in history • Shortness of breath gathering? • Pain History Taking 253 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. References: 1. Bickley LS, Szilagyi PG. Bates’ Guide to Physical Examination results from an FMRI study. Neuropsychopharmacology. and History Taking (9th ed.) with E-Book (Guide to Physical 2008;33(2):247–258. Exam & History Taking (Bates)). Philadelphia: Lippincott 20. Swahn MH, Bossarte RM. Gender, early alcohol use, and Williams & Wilkins; 2007. suicide ideation and attempts: fi ndings from the 2005 youth risk 2. Trautlein JJ, Lambert RL, Miller J. Malpractice in the emergency behavior survey. J Adolesc Health. 2007;41(2):175–181. department—review of 200 cases. Ann Emerg Med. 1984; 21. Cunningham R, Walton MA, et al. Past-year violence typologies 13(9 Pt 1):709–711. among patients with cocaine-related chest pain. Am J Drug 3. Considine J, Botti M, Thomas S. Do knowledge and experience Alcohol Abuse. 2007;33(4):571–582. have specifi c roles in triage decision-making? Acad Emerg Med. 22. Levis JT, Garmel GM. Cocaine-associated chest pain. Emerg 2007;14(8):722–726. Med Clin North Am. 2005;23(4):1083–1103. 4. Croskerry P, Sinclair D. Emergency medicine: a practice prone 23. Hodge AN, Marshall AP. Violence and aggression in the to error? Cjem. 2001;3(4):271–276. emergency department: a critical care perspective. Aust Crit 5. Juckett G. Cross-cultural medicine. Am Fam Physician. Care. 2007;20(2):61–67. 2005;72(11):2267–2274. 24. Ray MM. The dark side of the job: violence in the emergency 6. Novack DH, Dube C, Goldstein MG. Teaching medical department. J Emerg Nurs. 2007;33(3):257–261. interviewing. A basic course on interviewing and the physician– 25. Allely P, Graham W, McDonnell M, Spedding R. Alcohol levels patient relationship. Arch Intern Med. 1992;152(9):1814–1820. in the emergency department: a worrying trend. Emerg Med J. 7. McGuire BN, Ahmed AH, Regan T. Methods of obtaining 2006;23(9):707–708. a medical history in the emergency department. Academic 26. Ferns T, Cork A, Rew M. Personal safety in the accident and Emergency Medicine. 2001;8(5):469–470. emergency department. Br J Nurs. 2005;14(13):725–730. 8. O’Keefe JH, Bybee KA, Lavie CJ. Alcohol and cardiovascular 27. Casement PJ. Learning from the Patient. New York: The Guilford health: the razor-sharp double-edged sword. J Am Coll Cardiol. Press; 1992. 2007;50(11):1009–1014. 28. Tateno A, Jorge RE, Robinson RG. Pathological laughing and 9. http://www.cdc.gov/alcohol/ crying following traumatic brain injury. J Neuropsychiatry Clin 10. Boffetta P, Garfi nkel L. Alcohol drinking and mortality among Neurosci. 2004;16(4):426–434. men enrolled in an American Cancer Society prospective study. 29. Murube J, Murube L, Murube A. Origin and types of emotional Epidemiology. 1990;1(5):342–348. tearing. Eur J Ophthalmol. 1999;9(2):77–84. 11. Beulens JW, Hendriks HF. Alcohol and ischaemic heart disease. 30. Dominguez OJ, Jr. What’s so unusual? Emerg Med Serv. Lancet. 2006;367(9514):902; author reply 902. 2001;30(3):102. 12. Chao A, Thun MJ, Jacobs EJ, Henley SJ, Rodriguez C, Calle EE. 31. Dunckley M, Hughes R, Addington-Hall J, Higginson IJ. Cigarette smoking and colorectal cancer mortality in the cancer Language translation of outcome measurement tools: views of prevention study II. J Natl Cancer Inst. 2000;92(23):1888–1896. health professionals. Int J Palliat Nurs. 2003;9(2):49–55. 13. Villeneuve PJ, Mao Y. Lifetime probability of developing 32. Rollins G. Translation, por favor. Hosp Health Netw. lung cancer, by smoking status, Canada. Can J Public Health. 2002;76(12):41, 46–50. 1994;85(6):385–388. 33. Herman M, Le A. The crying infant. Emerg Med Clin North Am. 14. Calle EE, Miracle-McMahill HL, Thun MJ, Heath CW, 2007;25(4):1137–1159, vii. Jr. Cigarette smoking and risk of fatal breast cancer. Am J 34. Campbell SG, Sinclair DE. Strategies for managing a busy Epidemiol. 1994;139(10):1001–1007. emergency department. Cjem. 2004;6(4):271–276. 15. Pinto BM, Rabin C, Farrell N. Lifestyle and coronary heart 35. Moskop JC, Marco CA, Larkin GL, Geiderman JM, Derse disease prevention. Prim Care. 2005;32(4):947–961. AR. From Hippocrates to HIPAA: privacy and confi dentiality 16. Hughes JR. Clinical signifi cance of tobacco withdrawal. in emergency medicine—part II: challenges in the emergency Nicotine Tob Res. 2006;8(2):153–156. department. Ann Emerg Med. 2005;45(1):60–67. 17. http://www.cancer.gov/cancertopics/factsheet/Tobacco/ 36. Moskop JC, Marco CA, Larkin GL, Geiderman JM, Derse cessation AR. From Hippocrates to HIPAA: Privacy and confi dentiality 18. Daniel JC, Huynh TT, Zhou W, Kougias P, El Sayed HF, Huh J, et in emergency medicine—part I: conceptual, moral, and legal al. Acute aortic dissection associated with use of cocaine. J Vasc foundations. Ann Emerg Med. 2005;45(1):53–59. Surg. 2007;46(3):427–433. 37. Olsen JC, Sabin BR. Emergency department patient perceptions 19. Jager G, de Win MM, van der Tweel I, Schilt T, Kahn RS, van of privacy and confi dentiality. J Emerg Med. 2003;25(3): den Brink W, et al. Assessment of cognitive brain function 329–333. in ecstasy users and contributions of other drugs of abuse: 254 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. KEY CONCEPTS: Upon completion of this chapter, it is expected that the reader will understand these following concepts: • The four components of each physical exam • When a focused history and physical exam should be conducted on the scene or a rapid physical exam is appropriate • Detailed physical examination and its appropriate use • Matching the proper physical assessment with the patient’s presentation or chief complaint • The ongoing assessment as a repeat of the initial assessment and used to detect trends Case Study: Two new students were in the back of the room, bored. They asked each other, “Why do we bother doing a physical exam? The nurses don’t pay attention to us and the docs just repeat everything.” The instructor for the class, a senior Paramedic, said,” Come over here. I’ll bet that after a few minutes, you can fi gure out whether this ‘patient’ has pneumonia or congestive failure. You can also select the correct treatment as the wrong one can worsen your patient’s condition.” After practicing for a while, the students were convinced! 256 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Physical Examination and Secondary Assessment 257 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. OVERVIEW After performing the initial assessment and determining patient priority, the next step in patient assessment is to conduct the appropriate history and physical exam. This chapter reviews the basic components of a focused assessment. It also provides techniques for gathering a patient’s vital signs. In this chapter physical assessments are identifi ed by mechanism of injury or the patient’s chief concern. The detailed physical examination is performed on a patient to determine additional information. However, it may not be appropriate for all patient encounters. The ongoing assessment is also a critical component that allows the Paramedic to alter the treatment plan if needed based on established trends. The ongoing assessment is a repeat of the initial assessment, which is performed continuously throughout the patient encounter. Physical Examination vital signs to complete the physical examination. The Para- medic then combines these physical examination fi ndings, During a |
physical examination (also called exam), the Para- the vital signs, and the history (discussed in Chapter 15) and medic performs an assessment of the patient from head to formulates a treatment plan for the patient. These skills are toe in an effort to detect signs associated with a disease or critical. Although these skills were probably addressed in the condition. This may include signs that confi rm that a disease Paramedic’s basic EMS classes, they will be expanded for the or condition is present, thus helping the Paramedic decide Paramedic as a higher skill level is required. which condition is most likely causing the patient’s chief con- cern during this encounter. One example is auscultation of Inspection the breath sounds to decide whether the patient’s shortness Inspection is a physical examination technique that involves of breath is due to heart failure or asthma. The physical exam looking at the patient (Figure 16-1). This can take many forms may also detect signs of a disease or condition that is pres- depending upon the specifi c body system under inspection. ent and not related to the patient’s chief concern, but which The Paramedic should observe the patient and her immedi- may need to be addressed by the Paramedic. For example, ate environment. Observing the patient’s posture and apparent when evaluating a patient who complains of chest pain, the level of distress can give clues to the severity of the illness. Paramedic may determine, by the patient’s history, that the Making observations about the environment in which the condition is cardiac in nature. This could lead the Paramedic Paramedic fi nds the patient can help in determining the mech- to decide that the patient has developed heart failure during anism of injury, the patient’s ability to carry out the activities this cardiac event after auscultating the breath sounds. of daily living, or hazards in the patient’s living environment By developing excellent physical examination skills, the that may lead to future injury or illness. Observing the envi- Paramedic can determine a treatment plan when the history ronment may allow the Paramedic to discover information that does not clearly provide a guide. These skills are also impor- leads to additional history taking. Make note of such things as tant in situations where the history is not obtainable, as in the mechanism of injury, medication bottles, any evidence of any case of an unconscious patient. Excellent physical examination illicit drug or alcohol use, and general living conditions.2,3 skills develop through practice, understanding the pathophysi- Examples of body system-specifi c fi ndings from inspec- ology of disease, and understanding how diseases commonly tion include discovering lacerations, ecchymosis (bruising), present themselves.1 Whether performing clinical rotations or or abrasions in an injured extremity; observing jugular being a practicing Paramedic, it is helpful to ask the ED prac- venous pressure during a cardiovascular exam; or observ- titioners to point out interesting examination fi ndings. This ing the abdomen for distention. These fi ndings are discussed helps Paramedics recognize them on future patients. later in the chapter during the system specifi c examinations. As inspection is diffi cult to fully accomplish with a Physical Examination Techniques clothed patient, it typically requires the patient to be exposed. J udgment is required to balance the need for a complete exam- There are four components to every physical exam: ination and the need to keep the patient warm ( considering (1) inspection, (2) auscultation, (3) palpation, and (4) per- the environment in which the examination is occurring) and cussion. These four components are the essential “hands on” the patient’s modesty intact. Certain components of inspec- techniques used to assess the patient. In addition to these four tion may need to wait until the patient is moved to the relative techniques, the Paramedic routinely measures the patient’s privacy of the ambulance. 258 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. made up of a hollow fl exible tube connected to ear pieces that are placed in the Paramedic’s ears. The other end of the stetho- scope comes in several different sizes (depending on whether the patient is a neonate, adolescent, or adult) and typically consists of two heads: one that is fl at (called the diaphragm) and one that is cup-shaped (called the bell) (Figure 16-2). The diaphragm is covered with a thin plastic membrane and acts like the tympanic membrane (eardrum) to amplify and transmit sounds up the stethoscope to the Paramedic’s ears. The diaphragm is placed fi rmly against the bare skin (Fig- ure 16-3a) and is used to pick up higher pitched sounds (e.g., breath sounds). In contrast, the bell is placed lightly on the bare skin (Figure 16-3b) and is used to pick up lower pitched sounds (e.g., the whoosh of a carotid bruit). If the bell is held too tightly against the skin, the skin will stretch tight and act like the diaphragm. In this case, it will lose the ability to detect the lower pitched sounds.4,5 When auscultating the patient, note both normal or abnormal sounds, the location of the sounds, and the intensity of the sounds. Specifi c auscultation techniques and fi ndings will be detailed later in this chapter when discussing specifi c body system exams. Palpation Palpation is the most frequently used physical exam tech- Figure 16-1 Inspection of a trauma patient’s nique. It involves the provider placing his hands or fi ngers abdomen for ecchymosis. on the patient’s body in an effort to detect any abnormali- ties. Palpation can take many forms depending upon the abnormality the Paramedic is assessing. Different forms Auscultation of palpation can be used to assess for stability and assess Auscultation is assessing the patient through listening. The for tenderness. Deep palpation can be used to assess deeper assessment tool used during auscultation, the stethoscope, is structures (e.g., deep palpation of the abdomen to detect Tubing Bell Diaphragm Earpieces Figure 16-2 Anatomy of a stethoscope. Physical Examination and Secondary Assessment 259 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. (a) (b) Figure 16-3 (a) Auscultation using the diaphragm. (b) Auscultation using the bell. tenderness or masses) (Figure 16-4a), while light palpa- Vital Signs Measurement tion can be used to assess for superfi cial fi ndings (e.g., Vital signs are objectively measured characteristics of basic light palpation of the anterior chest wall to detect subcu- body functions. Vitals signs provide the Paramedic with an taneous emphysema) (Figure 16-4b). Firm palpation along indication as to how well the patient’s body is functioning a bony structure can assess for tenderness or crepitus or compensating for an injury or illness. Historically, the (Figure 16-4c). The stability of a joint may be assessed by vital signs included pulse, respirations, blood pressure, and fi rmly grasping the bones distal and proximal to the joint temperature. In the late 1990s, with the emphasis on appro- and applying stress to the joint’s connective tissues (Figure priate assessment of pain and discomfort by all medical 16-4d). Specifi c fi ndings and palpation techniques are dis- professions, the Joint Commission on Hospital Accredita- cussed later in this chapter. tion suggested adding the assessment of the patient’s pain as the fi fth vital sign, even though pain is technically clas- Percussion sifi ed as a symptom.6,7 Finally, some consider measurement Percussion is the act of lightly but sharply tapping the of the patient’s peripheral oxygen saturation (SpO2), also body surface to determine the characteristics of the under- known as pulse oximetry, as the sixth vital sign. Assessment lying tissue. It is performed by sharply striking the hyper- of the patient’s vital signs is reviewed in the following text extended distal joint of one middle fi nger with the tip of and the concept of assessing for orthostatic hypotension is the partially fl exed middle fi nger of the other hand (Figure discussed. 16-5). Percussion assesses whether the underlying tissues are air-fi lled, fl uid fi lled, or solid by the quality of the per- Pulse cussion note. Air-fi lled structures will produce a hollow, The pulse can be assessed at one of several locations tympanic percussion note similar to that of a drum. Fluid- where a major artery lies close to the surface of the skin fi lled structures will produce a dull percussion note. This (Figure 16-7). The most easily accessed area for conscious can be simulated by taking a full plastic bottle of water, patients is the radial pulse at the wrist over the radial artery. laying it on its side, and percussing the bottle. Solid struc- For unconscious patients, the carotid pulse in the ante- tures will provide a loud, well-defi ned percussion note. rior neck is often used during the initial assessment. Other This can be simulated by performing percussion on a table pulses the Paramedic may utilize are the femoral pulse at or desk. the patient’s groin and the dorsalis pedis (DP) pulse over Due to the high level of background noise in the fi eld, it the dorsum of the foot. Assess the pulse for rate, rhythm, is often diffi cult to hear the percussion note generated dur- and quality. The pads of the fi ngers are used to assess for the ing percussion. In that event, the Paramedic may be able to pulse by placing light pressure over the location of the pulse. modify the percussion technique and use her stethoscope to The pads of the fi ngers are used as they have more nerve amplify the percussion note (Figure 16-6). Percussion can add endings than the tips and can better detect the presence and valuable information to the patient examination. Specifi c per- quality of the pulse.8 Firm pressure can alter the perception cussion fi ndings and techniques will be discussed later in the of the pulse quality and rhythm, or in some cases occlude the chapter. pulse completely. 260 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. (b) (a) (c) (d) Figure 16-4 Examples of palpation. (a) Deep palpation of the abdomen. (b) Light palpation of the anterior chest wall. (c) Palpation along a bony structure. (d) Assessing joint stability. Street Smart While it is relatively easy to detect a pulse in a normal patient, it can be very diffi cult to detect a carotid pulse when the patient is in cardiac arrest.9,10 This fact is emphasized by research that indicates laypeople could not reliably fi nd a pulse in patients in cardiac arrest. Subsequently, the American Heart Association removed pulse checks from its citizen CPR Figure 16-5 The technique of percussion. Note program and replaced it with “signs of life.” the fi nger position used by the Paramedic. Physical Examination and Secondary Assessment 261 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. (a) (b) Figure 16-6 Modifi cation of the percussion to allow improved detection of the percussion |
note. Table 16-1 Normal Pediatric Heart Rates by Age Temporal Patient Age Beats/Minute Carotid Newborn 120–160 Infant (0–5 months) 90–140 Infant (6–12 months) 80–140 Apical Toddler (1–3 years) 80–130 Brachial Preschooler (3–5 years) 80–120 School-ager (6–10 years) 70–110 Adolescent (11–14 years) 60–105 Radial Femoral Young or middle-aged adult (15–64 years) 60–100 A normal pulse rate for an adult is considered anywhere from 60 to 100 beats per minute. The normal pulse rates are different for children (Table 16-1). Bradycardia is defi ned Popliteal as a heart rate that is under 60 beats per minute for an adult or below the lower limit of normal for a child. Tachycardia is defi ned as a heart rate that is over 100 beats per minute for an adult or above the upper limit of normal for a child. While the most accurate way to determine the patient’s pulse Posterior tibial Dorsalis pedis rate is to count the number of beats that occur in one minute, two other methods also provide a reasonable determination of pulse rate. One method is to count the number of heartbeats in Figure 16-7 Common pulse points. a 15-second time period and multiply that by four. A second 262 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. is to count the number of beats in a 30-second time period quality. An injury to an upper extremity may cause the radial and multiply that by two. If the patient’s pulse is regular, pulse to be absent in that extremity. Peripheral vascular dis- the shorter time can be used to determine an accurate pulse ease in a lower extremity, which decreases blood fl ow to that rate. The more irregular the patient’s pulse, the longer time is extremity, can cause a decrease in pulse quality compared to required to determine an accurate estimate of the pulse rate. the upper extremities. In some cases, the pulse is so irregular or the rate changes so Finally, it is important to note that the pulse rate palpated rapidly that a range of pulse rates is reported (e.g., the patient’s by the Paramedic, which determines the patient’s mechanical pulse rate varies between 120 and 140 beats per minute). pulse rate, may be different than the heart’s electrical rate as Generally, the Paramedic can assess the pulse rate by pal- shown on an electrocardiogram (ECG) rhythm monitor. pating the pulse at one of the locations previously described. However, when the patient is signifi cantly tachycardic, in the 180 to 220 beats per minute range, it can be diffi cult to count Street Smart the pulse rate using palpation. In this situation, the Paramedic may need to use a stethoscope to listen to the heart and count an apical pulse, or the pulse rate at the chest. In infants and During shock, the patient will lose distal pulses toddlers, where the normal heart rate is well over 100 beats fi rst (i.e., radial before femoral and femoral before per minute, the Paramedic may also need to assess the apical carotid). A quick survey of pulses can be helpful in pulse rate (Figure 16-8). Assess the rhythm of the pulse to determine its regularity. establishing the presence of shock. However, no Is the rhythm regular or does the timing between individual statement can be made about the patient’s blood beats vary signifi cantly? Are there premature beats that occa- pressure based upon the presence or absence of distal sionally and briefl y interrupt the underlying regular rhythm, pulses. or is the rhythm chaotically irregular, one that does not follow any pattern? This chaotically irregular pulse is sometimes termed an irregularly irregular pulse to indicate the complete absence of a pattern to the pulse rhythm. Respirations Pulse quality is a description of the amplitude or strength Respirations are assessed by observing the respiratory rate, of the pulse at that particular location. Pulse quality is often depth, pattern, and work of breathing. The respiratory rate is described as normal, absent, strong, bounding, weak, or assessed by watching chest rise or auscultating breaths with a thready. The term “thready” is usually given to pulses which stethoscope and counting the number of breaths (Figure 16-9). are both weak and very rapid, as seen with heart rates that The normal adult respiratory rate at rest is between 12 and 24 are signifi cantly tachycardic. Pulse quality may be different breaths per minute. The respiratory rate can be determined by depending on the location of the pulse and the patient’s condi- counting the number of respirations in either a full minute or tion. In a healthy individual free of disease or complaint, the the number of respirations in 30 seconds and multiplying that pulse quality should be the same regardless of the location count by two. In general, the respiratory rate is best counted of the pulse. However, some conditions will affect the pulse when the patient is not aware that the Paramedic is counting the rate. In contrast to the pulse rate, a patient can control his respiratory rate much easier than his pulse rate (Table 16-2). Figure 16-8 Paramedic assessing an apical pulse in a child. The stethoscope is held over the lower sternum to the left and the pulse rate is counted Figure 16-9 Paramedic assessing a patient’s as described in the text. respirations. Physical Examination and Secondary Assessment 263 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Table 16-2 Normal Respiratory Rate by Age Patient Age (yr) Breaths/Minute Infant (birth-1) Initially 40–60; rate drops to 30–40 after a few minutes; slows to 20–30 by 1 year Toddler (1–3) 20–30 Preschooler (3–5) 20–30 School-ager (6–10) 15–30 Adolescent (11–14) 12–20 Young or middle-aged adult (15–64) 12–20 Older adult (65) Depends on patient’s health Along with the rate, the Paramedic should note the depth 1. Eupnea (normal) of respiration. The depth can be described as shallow, nor- mal, or deep. A shallow respiration is less than the normal chest excursion and typically produces an inadequate respi- 2. Tachypnea 3. Bradypnea ration. Another term used to describe shallow respirations is hypoventilation. Hypoventilation can be caused by drug overdose, head injury, or other conditions that can cause 5. Cheyne-Stokes coma. A deep respiration is deeper than normal and is termed 4. Apnea hyperventilation. Examples of conditions that can cause hyperventilation include respiratory distress, a metabolic condition, or drug overdose. 6. Biot’s 7. Apneustic The respiratory pattern is considered the rhythm of the respirations. The respiratory pattern is the combination of the timing of the respirations and the depth of respirations 8. Agonal 9. Shallow (F igure 16-10). Different causes exist for many of these abnormal patterns (Table 16-3). 10. Hyperpnea 11. Air trapping Street Smart 12. Kussmaul’s 13. Sighing The Paramedic should be prepared to assist ventilations whenever a patient is either hypoventilating or hyperventilating, as both of these Figure 16-10 Abnormal respiratory patterns. respiratory situations can represent ineffective ventilation.11,12 Table 16-3 Selected Abnormal Respiratory Patterns, Their Description, and Cause Pattern Description and Cause Cheyne-Stokes Gradually increasing rate and tidal volume, which increases to a maximum, then gradually decreases; occurs in brain stem injuries Biot’s Irregular pattern and volume, with intermittent periods of apnea; found in patients with increased intracranial pressure Agonal Slow, shallow, irregular respiration; results from brain anoxia Kussmaul’s Deep gasping respirations, representing hyperventilation, “blowing off” of excess carbon dioxide and compensation for an abnormal accumulation of metabolic acids in the blood; though possible in any patient with metabolic acidosis, best known with diabetic ketoacidosis Central neurogenic hyperventilation Deep, rapid, regular respiration; found in patients with increased intracranial pressure 264 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Accessory muscle use (a) Sternal retractions (d) (b) (c) (e) Figure 16-11 Signs of increased work of breathing. (a) Accessory muscle use. (b) Sternal retractions. (c) Rib retractions. (d) Tripod position. (e) Pursed lip breathing. The patient’s work of breathing is also assessed to to breathe and accessory muscles are recruited to help measure the level of respiratory distress. There are several expand the rib cage, allowing the patient to inhale. When signs that indicate an increased work of breathing. During these muscles are used, they tend to become more defi ned normal respiration, the chest expands effortlessly. When (Figure 16-11a). When the work of breathing increases, a patient is in respiratory distress, more effort is required more effort is needed to generate the negative pressure in Physical Examination and Secondary Assessment 265 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. the thorax required for inspiration. When this happens, the provide the Paramedic with an indication about the blood skin at the top of the sternum and the skin between the volume status or compensation for illness in a given patient. ribs are pulled inwards because of this negative pressure Both the arterial and venous blood vessels have elasticity and in the chest. These fi ndings are termed sternal retrac- change vessel diameter in response to changes in fl uid vol- tions (Figure 16-11b) and rib retractions (Figure 16-11c), ume, pressure, and pathological conditions, with the arterial respectively. Patients in respiratory distress also will posi- system much more elastic than the venous system. Younger tion themselves in a way to help improve breathing. The patients can compensate for changes in pressure and volume tripod position (Figure 16-11d) is a sign that the patient status because of the increased elasticity of their blood ves- is in severe respiratory distress. This position allows the sels. The pulse pressure in an adult at rest is normally approx- overworked accessory muscles to work better, although imately 40 mmHg. Conditions that affect cardiac output, the most patients begin to tire when they are in such severe volume of blood pumped out of the left ventricle in one min- respiratory distress. Pursed lip breathing (Figure 16-11e) ute, can cause a decreased pulse pressure. In general, the dia- is another sign of increased work of breathing. When the stolic pressure holds relatively steady or drops slightly, while exhalation pressure is high, the alveoli tend to collapse dur- the systolic pressure drops more than the diastolic p ressure. ing exhalation. The patient puckers his or her lips while Conditions that cause a drop in blood fl uid volume (e.g., exhaling, providing some resistance to exhalation that pro- hemorrhage or shock from other causes) can cause a widen- vides pressure to keep the alveoli open.13–16 ing of the pulse pressure, especially in younger or otherwise fi t patients.18 Those patients may be able to initially sustain a Blood Pressure near normal or slightly decreased systolic pressure. However, Blood pressure is a measure of the pressure within the blood when the heart relaxes, the diastolic pressure is signifi cantly vessels that make up the circulatory system. The pressure will less than normal for that patient. Pulse pressure may provide vary depending |
upon the type of vessel and the phase of heart the Paramedic with an early clue to shock in patients who contraction. When the Paramedic measures blood pressure, otherwise appear to be stable. he is measuring the pressure within the arterial system. Blood To properly measure blood pressure, the patient’s arm pressure is measured at its maximum and minimum. The should be positioned at the level of her heart. Support the maximum blood pressure is measured during systole when patient’s arm at mid-chest level and center a properly sized the heart contracts, and is called the systolic blood pressure. cuff over the brachial artery of the arm (Figure 16-13). The The minimum blood pressure is measured during diastole blood pressure can be measured by either palpation or by aus- when the heart relaxes and fi lls, and is called the diastolic cultation. When measuring the blood pressure by palpation, blood pressure. These two levels of blood pressure are gen- the radial pulse is palpated by the Paramedic while infl ating erated by the heart’s intermittent contractions. Blood pressure the blood pressure cuff. The Paramedic infl ates the blood pres- can also be reported as a single pressure, the mean arterial sure cuff approximately 10 to 20 mmHg above the loss of the pressure (MAP), which is the average pressure in the arte- pulse, and then slowly defl ates the cuff until the pulse returns. rial system over time (Figure 16-12). A typical mean arte- The point where the pulse returns is the systolic pressure. rial pressure that will maintain adequate cerebral perfusion is When reporting a blood pressure measured by palpation, the about 60 to 80 mmHg.17 An adequate blood pressure is neces- Paramedic verbally reports the pressure “by palpation” (for sary for adequate perfusion of the body’s organs; however, a example, “124 by palpation”) and records the systolic pres- chronically elevated blood pressure can lead to increased risk sure as a fraction with a P as the denominator (e.g., 124/P). of catastrophic cardiovascular events. The palpation method is useful in situations where there is a The pulse pressure is defi ned as the difference between lot of ambient noise that would make it diffi cult to auscultate the systolic and diastolic pressures. The pulse pressure can the blood pressure. The auscultation method is a more accurate method of measuring blood pressure. The Paramedic places the blood pressure cuff on the patient’s arm as previously described and MAP = SBP + (2 × DBP) places the diaphragm of the stethoscope over the brachial artery (Figure 16-14).19 The Paramedic infl ates the cuff until 3 the sound of the heartbeat disappears and infl ates the cuff MAP = mean arterial pressure an additional 10 to 20 mmHg. Next, the Paramedic slowly SBP = systolic blood pressure defl ates the cuff at a rate of approximately 2 to 3 mmHg per second and notes the pressure at which she hears the sounds of DBP = diastolic blood pressure at least two consecutive beats. This is the systolic blood pres- sure. The Korotkoff sounds heard during the infl ation and Figure 16-12 Computing mean arterial pressure defl ation of the cuff are caused by the change in the nature of (MAP). Many automated noninvasive blood blood fl ow though the artery.20,21 To obtain the diastolic blood pressure monitors automatically calculate and pressure, the Paramedic continues defl ating the cuff slowly, display MAP. until she notes a muffl ing and then a disappearance of the 266 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Figure 16-13 Proper placement of a blood pressure cuff helps ensure accurate measurement. Figure 16-14 Measuring the blood pressure by auscultation. Korotkoff sounds. This is the diastolic blood pressure. The limit of normal indicates hypertension. A systolic blood pres- Paramedic records both systolic and diastolic blood pressure sure below the lower limit of normal indicates hypotension. readings to the nearest 2 mmHg. In an adult, a blood pressure greater than 139 mmHg systolic Blood pressure readings vary signifi cantly with patient or 89 mmHg diastolic are always considered abnormally ele- age, underlying physical and medical conditions, and current vated and a systolic pressure below 90 mmHg is considered medications. A systolic blood pressure that is above the upper abnormally low (Table 16-4). Physical Examination and Secondary Assessment 267 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Table 16-4 Normal Blood Pressures Blood Pressure (mmHg) Patient Age (Years) Systolic Diastolic Infant and toddler (0–3) 80 (2 times age in years) Two-thirds systolic Preschooler (3–5) 78–116 average 55 School-ager (6–10) 80–122 average 57 Adolescent (11–14) 88–140 average 59 Young and middle-aged adult (15–64) 90–150 60–90 Older adult (65) Depends on patient’s health Depends on patient’s health Temperature the color of the mucous membranes in the mouth, the palms The body’s normal core temperature ranges from 36.1°C to of the hands and soles of the feet, or the conjunctiva (Fig- 37.7°C (97°F to 99.8°F). A temperature above 38°C (100.4°F) ure 16-16) in darker skinned patients to determine skin color. is considered a fever. An elevated body temperature is called Skin condition is generally categorized as normal, dry, moist, hyperthermia. In contrast, hypothermia is defi ned as a or diaphoretic. A patient with diaphoretic skin is sweat- body temperature less than 35°C (95°F). Relatively accurate ing profusely. This state is associated with many different estimates of core temperature can be obtained from oral, rec- conditions. tal, or tympanic thermometers (Figure 16-15), with the rectal temperature as the most accurate estimate of the core body Pain temperature. As previously discussed, assessment of pain was consid- ered the fi fth vital sign by the Joint Commission on Hospital Skin Condition and Color Accreditation in the late 1990s in an effort to strongly encour- Skin condition and color is an important indicator of the age all healthcare providers to adequately assess every patient patient’s ability to provide suffi cient oxygen-rich blood to the for pain and reassess the patient after interventions.22,23 Vari- tissues. While there is a wide range of normal skin tones, ous pain scales have been developed in an attempt to quantify normally many fair skinned individuals will have a pink the amount of pain. However, pain assessment is still a sub- color or tone to the skin. The Paramedic may need to assess jective report that varies between patients. A more detailed Figure 16-15 Measuring temperature with a tympanic thermometer. (Courtesy of Melissa King/iStockphoto) 268 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. discussion of the pain scales useful for the prehospital envi- ronment can be found in Chapter 15. Pulse Oximetry Hemoglobin is the molecule in red blood cells that accepts oxygen in the lungs and carries it to the body’s tissues to allow cellular respiration. Pulse oximetry is a noninvasive measurement of the percentage of hemoglobin in arterial blood that is bound to oxygen molecules.24 An accurate read- ing provides the Paramedic a good measure of the patient’s oxygenation, or his ability to move oxygen from the air in the lungs into the blood. It does not provide an indication of how well the patient is using that oxygenation. It also does not provide an indication of the patient’s ventilation, or note how well the patient is moving air in and out of the lungs during inhalation and exhalation. A normal pulse oximetry value in a healthy individual without lung disease is between 96% and 100% saturation. For individuals with chronic lung diseases, the patient’s personal normal pulse oximetry may actually be as low as 85% without supplemental oxygen.25 Pulse oximetry is determined by measuring the change that occurs when a beam of red light and infrared light is directed across a capillary bed. When hemoglobin binds to oxygen, it will cause an imperceptible change in the red and infrared light as it passes through the pulsating capillary bed. This change is translated into a percentage of oxygen satura- tion that is displayed for the Paramedic. Some pulse oxime- Figure 16-16 Assessing the conjunctiva for ters provide a waveform display in addition to the numerical pallor that may indicate anemia or blood loss. value (Figure 16-17). This waveform fl uctuates with changes (Courtesy of CDC/Dr. Lyle Conrad) in the patient’s blood fl ow during normal contraction of the patient’s heart. Because it is simple to measure the rate of these fl uctuations, most oximeters will provide the patient’s pulse rate in addition to the oxygen saturation. Figure 16-17 Normal pulse oximetry waveform. Notice the fl uctuations that correspond with the patient’s pulse rate (red arrow). Physical Examination and Secondary Assessment 269 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Figure 16-18 Poor oximetry waveform (red arrow). Several factors may affect the accuracy of the pulse Capnography o ximetry reading. In order for the reading to be accurate, the The process of respiration includes the following steps patient must have suffi cient blood fl ow in the capillary bed of ( Figure 16-19): the body part where the probe is attached. If the waveform is poor (Figure 16-18), then the oximeter will either not read or ■ Inhalation of oxygen-containing air into the lungs will provide an inaccurate reading. Blood fl ow to the capillary ■ Movement of oxygen from the air across the alveolar bed is decreased if the limb is cool, if the patient is hypo- membrane into the blood volemic (decreased circulating blood volume), or the patient is ■ Movement of oxygen through the blood to the tissues hypotensive. Traditional pulse oximeters only detect whether ■ Absorption of oxygen into the cells or not the hemoglobin is bound to another molecule. Other ■ Production of carbon dioxide by the cells as they use the compounds (e.g., carbon monoxide) can also bind to hemoglo- oxygen and glucose for fuel bin in the red blood cells. If carbon dioxide is present, the pulse ■ Delivery of carbon dioxide back to the lungs oximeter will still read a normal saturation level, even though ■ Movement of the carbon dioxide back across the alveolar the patient’s tissues do not receive suffi cient oxygen and are membrane into the lungs hypoxic.26 Newer co-oximeters utilize additional wavelengths ■ Exhalation of the carbon dioxide into the atmosphere. of light and can detect the presence of carbon monoxide and other compounds that can bind to hemoglobin. From a respiratory system standpoint, the amount of It is important to note that even patients who present exhaled carbon dioxide is related to the patient’s ability to with a pulse oximetry reading within a normal range can move air in and out of the lungs. If the patient cannot venti- benefi t from supplemental oxygen. In many conditions, the late adequately, the concentration of exhaled carbon dioxide surface capillary beds utilized to measure oxygen saturation will |
increase because the patient exhales a smaller amount with may have fully saturated blood; however, due to blood loss each breath, allowing the carbon dioxide level to build up in the or hypotension, deeper vessels—including those supplying lungs. If the patient hyperventilates, the exhaled carbon dioxide the heart, brain, kidneys, and the intestines—may not have level will decrease because a larger amount of carbon dioxide is an adequate supply of oxygen. Blood itself not only carries exhaled with each breath, decreasing the overall concentration oxygen by hemoglobin in red blood cells, but can also carry of carbon dioxide in the lungs. In situations where the patient is dissolved oxygen molecules within the plasma, or liquid por- able to circulate the blood adequately, capnography provides an tion of the blood. Patients who are in respiratory distress or indication of how well the patient is able to ventilate. suffering from a signifi cant illness or injury should receive From a circulatory standpoint, the amount of exhaled car- supplemental oxygen to ensure the organs continue to receive bon dioxide is directly related to the body’s ability to perfuse a suffi cient amount of oxygen. the tissues, or carry oxygen, glucose, and other nutrients to 270 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Alveoli O2 CO2 O2 O O2 2 O2 O2 O Cells 2 Blood vessel CO2 CO2 CO2 O2 Alveoli O2 CO2 CO2 CO2 Figure 16-19 The process of respiration. the cells in order to carry on the metabolic processes required 50 Exhalation/Inhalation to sustain life.27 If the patient is perfusing well, the carbon dioxide produced by the metabolic processes inside the cells 40 * will be transported back to the lungs for exhalation. Condi- 30 tions that decrease the patient’s ability to circulate the blood (e.g., shock and cardiac arrest) will decrease the level of car- 20 bon dioxide in the lungs. Waveform capnography provides a graphical representa- 10 tion of the exhaled carbon dioxide level over time.28,29 The 0 level of carbon dioxide will vary with inhalation and exhala- Time tion (see the curve shown in Figure 16-20). The normal level of exhaled carbon dioxide is approximately 40 mmHg. End- *Peak EtCO2 level tidal carbon dioxide levels (EtCO ) below 10 mmHg in the 2 Figure 16-20 Typical capnography waveform. setting of cardiac arrest is associated with a 0% chance of sur- vival. Elevated levels are seen in patients who are not ventilat- ing adequately. A decrease in EtCO level during mechanical tube by the change in waveform before the patient’s oxygen 2 ventilation may indicate the patient has become hypotensive. saturation is affected (Figure 16-21).30–32 The use of wave- It could also mean the ventilation rate is too high and should form capnography is discussed further in Chapter 25. be slowed to a lower rate. The waveform’s shape and pattern can provide clues to the disease process in patients complain- Orthostatic Vital Signs ing of shortness of breath. Finally, using EtCO with patients Orthostatic vital signs are vital signs that change with posi- 2 who are intubated is an excellent patient safety tool, as the tion. When an individual changes position from lying down Paramedic can immediately detect a dislodged endotracheal to standing, the blood pressure normally has a tendency to Physical Examination and Secondary Assessment 271 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. CO2 (mm Hg) 50 in pulse rate with position change could reasonably detect 40 blood loss of between 500 mL and 1 L.36 Care must be taken 30 20 when measuring orthostatic vital signs on a patient, espe- 10 cially when assuming the standing position. If the patient 0 develops severe symptoms on changing position, measure- Time ment should not be completed, as it puts the patient at risk for fall and injury. Figure 16-21 Sudden loss of the waveform in an intubated patient likely indicates endotracheal tube dislodgement. Concern-Based Physical Exam Conceptually, every call for assistance begins with a patient’s chief concern or complaint. This is true whether the call drop due to gravity. The body will compensate initially for was received emergently through the 9-1-1 system or non- this drop in blood pressure by constricting the arterial sys- emergently through a secondary system. From a dispatch per- tem.33 If that does not provide suffi cient compensation, then spective, the algorithms used to determine response resources the heart rate will increase in an effort to maintain an ade- are keyed from the patient’s or caller’s chief concern. From quate blood pressure. If the patient has a decreased blood a Paramedic perspective, the chief concern is used to help volume, whether through hemorrhage or through dehydra- focus the history and physical examination to fi nd the most tion, the body will not be able to completely compensate for likely cause of the patient’s chief concern and detect life- or this change by decreasing the size of the blood vessels alone. limb-threatening conditions that are associated with that con- Therefore, measuring orthostatic vital signs can assess the dition. Detailed physical examinations are time-consuming patient for subtle volume loss that may not be evident during and often provide more information than what is useful to the a supine or a seated set of vital signs. To measure orthostatic Paramedic. During most patient contacts, the Paramedic will vital signs, the Paramedic measures the blood pressure and perform a focused physical exam based upon the patient’s heart rate in the supine, sitting, and standing positions with chief concern. at least one minute rest between position changes to allow the body to compensate for the change. Although this may be Focused Exam Matrix diffi cult to achieve in the prehospital environment, it is inad- visable with patients who have sustained suffi cient trauma to In the prehospital environment, detailed head to toe exams require spinal motion restriction. are not practical for many patients. Instead, a focused physi- Positive orthostatic vital signs are defi ned as a heart cal exam is performed on the systems associated with the rate increase of 20 beats per minute or greater, a systolic patient’s chief concern. The Paramedic performs a detailed blood pressure drop of greater than 20 mmHg, a diastolic examination of one or two related body systems and a brief blood pressure increase of 10 mmHg, and/or dizziness or examination of other relevant body systems. In this way, the lightheadedness with position change.34,35 While ortho- Paramedic can effi ciently use her time during the patient static vital signs have been traditionally used as a means of contact and assess for fi ndings that can help confi rm the determining blood loss or hypovolemia in patients who had paramedical diagnosis suspected by the history or suggest otherwise normal vital signs, other factors—including med- alternate conditions that require assessment. ication, age, ingested substances (e.g., alcohol), and other The physical examination is also guided by the complex- medical conditions—can also produce orthostatic changes. ity of the patient’s chief concern. A patient who is complaining In several studies specifi cally looking at blood loss, changes of ankle pain after twisting his right ankle on the sidewalk and did not strike any other part of his body may be appropriate for a single system-focused exam on that ankle. A patient with Street Smart a strong cardiac and respiratory history complaining of gen- eral weakness may require a more extensive physical exami- nation. The discussion throughout the rest of the chapter will Two Paramedics should take orthostatic vital signs. provide a guide to the elements of the physical examination One Paramedic remains dedicated to watching the that should be covered based upon the patient’s chief concern. patient. Any change in level of consciousness, ability It is not meant to be all inclusive, and should be modifi ed by the Paramedic based upon clinical judgment, the specifi c to remain in the necessary position, or complaint of patient’s presentation, and examination fi ndings that suggest new or worsening symptoms is enough for the fi rst other conditions that may contribute to the chief concern. Paramedic to cancel the remainder of the orthostatic Both the focused and detailed physical examinations take place after correcting life-threatening conditions that vital signs. The second Paramedic is dedicated to were discovered during the primary assessment. Some of the measuring the pulse and blood pressure. items assessed during the focused or detailed examinations are items that were assessed during the primary assessment. 272 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. CO2 (mm Hg) Table 16-5 Physical Examination by Chief Concern (CC) Chief Concern Primary System Secondary System Tertiary System Chest pain Cardiovascular Respiratory Neurological Gastrointestinal Shortness of breath Respiratory Cardiac Neurological Abdominal pain Gastrointestinal Cardiac Loss of consciousness Neurological Cardiac Musculoskeletal Altered mental status Neuorological Psychiatric Musculoskeletal Musculoskeletal Skin Psychiatric Psychiatric Neurological They should be reassessed during the focused exam as neces- Once the primary assessment is completed, the focused sary to provide the Paramedic with the information needed to assessment follows. As part of the focused physical exam, effi ciently and adequately treat the patient. some general features should be assessed for every patient. These features include vital signs, appearance, and the scene. Examination Matrix All three of these features are part of the Paramedic’s initial An examination matrix (Table 16-5) provides a guide to the impression; an assessment of these features should be per- systems the Paramedic should assess based upon the patient’s formed during every single patient encounter. chief concern. The table is divided into columns that indicate The constitutional examination consists of the assess- the primary system to focus upon during the exam, as well as ment of the patient’s vital signs. At a minimum, this includes a secondary and a tertiary system to include in the examina- the blood pressure, pulse, and respirations. The Paramedic tion. The primary system is most closely associated with the should obtain a baseline set of vital signs on every patient conditions that produce the chief concern listed in the fi rst after completing the primary assessment. A room air pulse column. The secondary system is also associated with condi- oximetry reading should also be obtained on patients with tions that can produce that chief concern, but not as closely. chief concerns that involve the respiratory system. If a ther- The tertiary system generally can be affected by disease con- mometer is available, the patient’s body temperature can be ditions from the other systems that cause the chief concern. assessed. The patient’s approximate weight is also important For example, the chief concern of shortness of breath has the in determining medication dosages for certain medications. respiratory system as its primary system. However, cardiovas- At least two sets of vital signs should be taken during every cular conditions (e.g., angina) can cause shortness of breath. patient encounter as an assessment of stability and to identify The cardiovascular system is listed as the secondary system. changes during treatment. The neurological system may have fi ndings associated with The patient’s appearance can also provide an indica- shortness of breath, so it is listed as the tertiary system in the tion of her ability to compensate for the disease process. matrix under the shortness |
of breath chief concern. Document the position in which the patient was found (e.g., As previously discussed, this matrix should be used to “seated on the couch” or “supine on the ground 50 feet from guide the Paramedic’s focused physical examination based the vehicle”). The level of distress experienced by the patient upon the patient’s chief complaint. The systems and features on initial contact should also be noted as part of the consti- examined in a specifi c patient may be different based upon tutional examination. This may include distress from painful the history obtained from the patient as well as the Paramed- conditions or respiratory distress. Skin condition and color ic’s fi ndings. can also provide clues toward level of distress and compensa- General Exam tion for the disease process causing the chief concern. The patient’s position may provide clues to the level of distress. In Chapter 13, an algorithmic approach was discussed for per- For example, a patient in severe respiratory distress may be forming the primary assessment in every patient. During the leaning forward in a tripod position to help ease her breath- overall scene assessment, the Paramedic assesses the scene ing. A patient experiencing the pain from a kidney stone may to determine and call for appropriate resources to handle the not be able to sit still and will pace or roll on the stretcher in situation. On each individual patient, the goal of the primary an attempt to fi nd a comfortable position. assessment is to rapidly detect and treat any life-threatening Observations made about the scene also provide impor- conditions (e.g., inadequate respirations, shock, or massive tant clues to the Paramedic and the ED staff. During the pri- bleeding). Triage algorithms based on the primary assess- mary assessment, the Paramedic views the scene for hazards ment exist to help the Paramedic treat and transport patients to his health and safety. As part of the focused exam, the in order of severity. scene should be viewed for evidence of the patient’s ability Physical Examination and Secondary Assessment 273 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. to care for herself. A patient with a disheveled appearance external jugular veins will distend, or stretch and become with torn and dirty clothing in an unkempt apartment may not larger. This can be measured by positioning the patient in a be able to care for herself. Empty pill bottles present at the semi-Fowler’s position at approximately a 45-degree angle, scene of a patient who has altered mental status may suggest asking her to turn her head away from you, and inspecting the an intentional overdose. For trauma patients, the scene can external jugular vein for distention (Figure 16-22a).38 It can provide important clues as to the mechanism of injury that be helpful for the Paramedic to shine a penlight perpendicu- can help focus the Paramedic’s examination to areas most lar across the vein to improve visualization. In a patient with likely injured. Position in the vehicle, restraint use, or prox- a normal jugular venous pressure, the external jugular vein imity to hazards all provide the Paramedic with important will be distended about three centimeters above the sternal information. notch. Distention greater than three centimeters above the sternal notch is considered an elevated JVP (Figure 16-22b). Chest Pain Inspect the patient’s extremities for peripheral edema, a condition that also can indicate heart failure. The most com- Approximately 15 million Americans suffered from cardio- mon areas where peripheral edema occurs are in the ankles vascular diseases in 2004, with half of those people suffering and feet. However, edema can occur up into the thighs and a myocardial infarction.37 Heart disease remains the top cause scrotum in males and external labia in females, as well as in of death in the United States. Chest pain is one of the more the upper extremities. Pitting edema is a term that refers to common chief concerns which patients provide to dispatchers the amount of indention produced when the edematous limb is during the 9-1-1 call and tell Paramedics during the patient pressed over the tibia by the examiner’s fi nger ( Figure 16-23). interview. As part of the focused examination, the Paramedic The level of pitting edema is often described as trace, mild, should assess the cardiovascular system as the primary sys- moderate, or severe based upon the size and duration of the tem, and the respiratory, gastrointestinal, and neurological indention. systems as the secondary and tertiary systems. The physical Auscultation of the heart involves listening to the heart examination elements for a patient with a chief concern of with the diaphragm of the stethoscope in four locations (Fig- “chest pain” are inspection, auscultation, and palpation. ure 16-24). Lightly hold the diaphragm of the stethoscope against the chest for approximately 20 seconds in each area. Cardiovascular System The normal sounds heard at these locations correspond to Inspection of features related to the cardiovascular system the heart valves closing during the contraction and relaxation starts with an assessment of jugular venous pressure (JVP). phases of the heart. The two normal heart sounds are called The jugular veins run on either side of the neck at an angle the S1 and S2 sounds (Figure 16-25a). The S1 sound corre- from the corner of the mandible to the mid-clavicle on the sponds to the closing of the mitral and tricuspid valve at the same side. The jugular veins feed into the large veins that beginning of systole, or ventricular contraction. The S2 sound feed into the superior vena cava and into the right atrium. corresponds to the closing of the aortic and pulmonic valves When the heart is not pumping effectively or when the patient at the end of systole, marking the beginning of diastole, or has a signifi cant amount of extra fl uid in the circulation, the ventricular relaxation and fi lling. Two extra heart sounds, S3 (a) (b) Figure 16-22 (a) Patient positioning for evaluation of jugular venous pressure. (b) Elevated jugular venous pressure. 274 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. NORMAL HEART SOUNDS 1+ 2+ 3+ 4+ 2 mm 4 mm 6 mm 8 mm S1 S2 S1 S2 S1 S2 A Figure 16-23 Assessment of the severity of peripheral edema. EXTRA SOUNDS S4 S1 S2 S3 B MURMURS S1 S2 S1 S2 S1 S2 Systolic Diastolic Aortic A P murmur murmur stenosis (heard best over aortic area) C T M Figure 16-25 Heart sounds. (a) Normal. (b) Extra sounds. (c) Murmurs. murmur associated with aortic stenosis. Aortic stenosis is Figure 16-24 Locations for auscultation of heart a condition in which the leafl ets of the aortic valve become sounds. A aortic area. P pulmonic area. scarred over time and the pathway through the valve narrows. T tricuspid area. M mitral area. The murmur associated with aortic stenosis is best heard over the aortic area and is a high-pitched, sometimes loud sound and S4, are diastolic sounds that occur with changes in ven- that begins just after the S1 sound and runs until just before tricular fi lling (Figure 16-25b). When either sound is present the S2 sound. This is clinically important because, in patients it is often called a gallop, as the combination of the normal with severe stenosis, a higher pressure is required to propel and extra sounds produces a galloping rhythm, similar to blood out of the left ventricle and into circulation. The patient hearing a horse gallop. The S3 sound is sometimes normal in tends to have signifi cant hypertension; however, this hyper- children and young adults as the heart fi lls quickly. In patients tension is necessary for the patient to circulate blood. Medi- with a chief concern of chest pain or shortness of breath, it cations that can lower the blood pressure should be used with can indicate fl uid overload associated with heart failure. The caution in patients with a loud murmur from aortic steno- S4 sound occurs close to the S1 sound and can indicate the sis (one that can almost be heard before the stethoscope is ventricles are stiff and are not fi lling properly. placed on the chest) as that higher blood pressure is essential Murmurs are abnormal heart sounds produced by tur- to maintain circulation. bulent blood fl ow across the four valves. Different types of Another abnormal heart sound that is sometimes heard murmurs are associated with different conditions and can is called a rub. A rub is a low-pitched, soft scratching sound occur during both systole and diastole. Many murmurs are that occurs at any time during the cardiac cycle and indicates described as a low pitched “whoosh” sound. This sound is pericarditis, or an infl ammation of the pericardial sac that sometimes separate from, and sometimes integrated with, the surrounds the heart. The sound of the rub is produced when normal heart sounds (Figure 16-25c). A discussion of all the the infl amed pericardium rubs against the heart muscle dur- different murmurs is beyond the scope of this text; however, ing heart contraction or relaxation. This sound can be diffi - one that may be clinically important to the Paramedic is the cult to hear in the loud prehospital environment. Physical Examination and Secondary Assessment 275 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Several features of the cardiovascular system are assessed by palpation. While auscultating the chest for heart sounds, the Paramedic can spread her fi ngers out over the diaphragm and simultaneously palpate the chest for a thrill, or vibration of the chest associated with heart contraction. Forceful con- tractions can produce a signifi cant pounding inside the chest wall, causing a heave. Peripheral pulses are also assessed by palpation for strength and equality in the left and right extremities. Capillary refi ll is a measure of the patient’s ability to perfuse the extremities with oxygenated blood. Capillary refi ll is assessed by squeezing the tip of a digit hard enough to blanch it, releasing it, and then counting the number of seconds for it to return to a normal color. A normal capillary refi ll is two seconds or less. A delayed capillary refi ll indi- Figure 16-26 A cyanotic patient. (Courtesy of cates poor perfusion.39 Wellcome Trust/Custom Medical Stock Photo) Blood pressure is normally equal in both arms. If pulses are unequal in both arms, assess the arms for a difference in systolic pressures. A signifi cant difference in blood pressure over the larger airways are called bronchial sounds. These in both arms can indicate a problem with the aorta. sounds are louder and sound like air rushing through a hollow tube. Normal respiration involves an inspiratory phase that is Respiratory System longer than the expiratory phase. In addition, there is good Assessment of the respiratory systems begins with inspect- movement of air in and out of the lungs. Certain conditions ing the patient for respiratory effort. Assessment fi ndings that cause a prolongation of the expiratory phase. For example, indicate the patient has increased respiratory effort include several abnormal lung sounds can indicate specifi c conditions use of accessory muscles, sternal or intercostal retractions, that help guide the |
Paramedic toward determining a cause for increased respiratory rate, or tripod positioning. Accessory the patient’s chief concern (Table 16-6). muscles of respiration include the muscles in the front of the neck. When the patient is in severe respiratory distress, these muscles contract to help lift the upper portion of the rib cage Street Smart during inspiration (Figure 16-11a). Sternal and intercostal retractions occur when the patient struggles to move air into the lungs (Figures 16-11b and 16-11c). Patients in severe To differentiate a pericardial rub from a pleural rub, respiratory distress will frequently assume a tripod position have the patient hold his breath. Pleural rubs are where they sit leaning slightly forward resting their hands on heard when the patient is breathing while pericardial their knees (Figure 16-11d) in an effort to improve their abil- ity to inhale. rubs occur with each heartbeat. The patient’s skin and mucous membranes should also be inspected for color. In a well-oxygenated patient, the mucous membranes will be pink. Cyanosis is a bluish hue that devel- Percussion of the chest can also offer additional informa- ops when the patient develops hypoxemia, or a decreased tion about lung fi ndings (Figure 16-5). One fi gure is placed oxygen level in the blood (Figure 16-26). In patients with a against the chest wall in-between two ribs while the other taps darker complexion, the Paramedic may have to inspect the the fi rst fi nger. This should be performed at several levels on oral mucous membranes or the nail beds to assess for cyano- both the left and right side of the chest, comparing sides for sis. In severe hypoxemia, the patient’s entire skin becomes equality. A normal chest percussion note is a somewhat hol- cyanotic. The Paramedic needs to intervene rapidly with low sound. A hyperresonant percussion note sounds similar supplemental oxygen, airway management, and ventilatory to striking a drum and indicates an increased amount of air support to correct the hypoxemia. in the chest. This is often seen with a pneumothorax on the The Paramedic should then auscultate the lungs for lung side of the hyperresonant percussion note. A hyporesonant sounds. Lung sounds should be assessed posteriorly and on percussion note is dull in character, and often indicates fl uid both sides of the chest, assessing both the left and right lung in the lung from either a pleural effusion or hemothorax. at the same level, so that sounds can be compared between Due to noise at the scene of the call, it may be diffi cult to the left and right lung. Normal sounds differ depending on assess a percussion note until the patient is in the back of the the location in the chest. Lung sounds auscultated over the ambulance. peripheral, smaller airways are called vesicular sounds, and Palpation of the chest is used to assess for stability of sound like leaves rustling in the wind. Lung sounds auscultated the rib cage, tenderness, equal expansion of the chest, and 276 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Table 16-6 Abnormal Lung Sounds Sound Description Conditions Associated Wheezing High-pitched sounds, often heard in inspiration, but can be Asthma present on expiration Chronic obstructive pulmonary disease (COPD) Heart failure Rales Crackles similar to Rice Krispies™ crackling in milk Fluid in smaller airways Heart failure Rhonchi Coarse crackling in larger airways Mucus in larger airways Acute bronchitis Pneumonia Consolidation Bronchial sounds heard over periphery, unequal compared to Pneumonia same fi eld on opposite lung Stridor High-pitched inspiratory upper airway sound Upper airway obstruction from upper airway edema or foreign body Absent • Specifi c fi eld • Pleural effusion, pneumonia, lower airway obstruction • Entire lung • Pneumothorax, hemothorax, massive pleural effusion Friction rub Intermittent coarse rubbing sound similar to sandpaper rubbing Indication of infl ammation of pleura with inspiration or expiration the presence of subcutaneous emphysema. Point tenderness Neurological along the rib or sternum may indicate a fracture in the set- The patient’s mental status is the best indicator of the brain’s ting of an injury to the chest. Place the hands on either side perfusion with oxygenated blood. All of the body systems are of the lower rib cage. During inspiration and expiration, the designed to support adequate blood fl ow and oxygen deliv- chest should expand equally with inspiration. Subcutane- ery to the brain. A normal mental status indicates that the ous emphysema is the presence of air between the layers of brain is receiving a suffi cient amount of oxygenated blood. the skin and indicates a leak in the respiratory system. Most An altered mental status, which may vary from confusion to often this is due to a pneumothorax with air escaping into the unconsciousness, can indicate that the brain is not receiving skin. At other times, it can occur after a tracheal or larger air- enough oxygenated blood. way rupture. Subcutaneous emphysema is often described as feeling like bubble wrap underneath the skin. Subcutaneous Put It All Together emphysema can become extensive, traveling up the neck into the face or down the abdomen into the genitals.40 The assessment of a patient presenting with the chief concern of chest pain includes many possibilities (Figure 16-27). Gastrointestinal The abdominal exam in a patient with a chief concern of chest Shortness of Breath pain is limited to assessing for pain and signs of fl uid over- Shortness of breath is another common chief concern of load related to right heart failure. The abdomen is palpated patients calling EMS. Shortness of breath occurs primarily to assess for tenderness, especially over the epigastrium, from respiratory causes (e.g., asthma or pneumonia), but can which may indicate a gastrointestinal origin for the patient’s also occur from cardiac causes (e.g., heart failure or angina). chief concern. Hepatojugular refl ux is assessed by plac- The physical exam for a patient with a chief concern of ing the patient in a semi-reclined position at approximately “shortness of breath” is similar to that of patients who have a a 45-degree angle. The jugular vein is fi rst assessed for level chief concern of chest pain. However, the emphasis is on the of distention (Figure 16-22). The Paramedic then applies fi rm respiratory system. pressure to the patient’s right upper quadrant over the liver. The hepatojugular refl ux is positive if the jugular vein disten- Respiratory tion increases. This is seen in conditions that cause the patient The Paramedic starts by inspecting the patient for respira- to become fl uid overloaded, including heart failure and kid- tory effort and cyanosis. As previously discussed, fi ndings of ney failure.41,42 severe respiratory distress are signifi cant and require rapid Physical Examination and Secondary Assessment 277 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Mental status Cyanosis Accessory muscles Jugular venous pressure (JVP) Lung auscultation Trachael position Heart Percussion note Blood ausculation pressure Chest palpation Radial pulses Capillary refill Hepatojugular reflux Abdominal palpation Peripheral edema Pedal pulse Capillary refill Figure 16-27 Assessment of a patient with the chief concern of chest pain. intervention. Also note if the patient appears to be tiring. described. Rales can indicate a cardiac cause for the short- As the respiratory distress progresses, the patient will begin ness of breath while many of the other sounds indicate a to grow weary of breathing. Immediate intervention at this respiratory cause. As previously described, a hyperresonant point with airway management is key to preventing respira- percussion note can indicate a pneumothorax while a dull tory arrest. One additional feature to assess is the tracheal percussion note can indicate fl uid or pneumonia if present position. Tracheal position is assessed just above the sternal in one lung fi eld. When palpating the chest, ask the patient notch (Figure 16-28). Normally, the trachea is found in the to speak. Vibrations palpated on the chest wall that occur center of the neck, centered in the sternal notch. Deviation of with speech are called tactile fremitus, and can also indi- the trachea toward one side can indicate conditions that cause cate an infective process in that portion of the lung. These a shift of the heart and lungs to one side, and is usually a late abnormal vibrations are produced as the vocal sounds are sign of the condition. transmitted into the lung and are altered in the area of the The Paramedic assesses the patient using auscultation infection, causing a vibration that can be palpated over that to identify normal and abnormal lung sounds as previously portion of the lung. 278 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Abdominal Pain Sorting out the cause of abdominal pain is challenging as the abdominal cavity contains many organs with a multi- tude of causes for pain. There are many conditions that cause abdominal pain; some are life-threatening while others are not. Following is the physical assessment for a patient who has a chief concern of “abdominal pain.” Gastrointestinal The focused examination of a patient with the chief concern of abdominal pain begins with an examination of the gastro- intestinal system. The abdomen is inspected for distention, or protruding of the abdomen past its normal size (Figure 16-30). Figure 16-28 Assessing for tracheal position. Localized protrusions at the umbilicus or in the midline of the abdomen may be a hernia, or openings in the muscle and tissue layers that allows the intestines to protrude through the opening. The abdomen is also inspected for prominent sur- face veins, especially around the umbilicus, that may indicate Cardiovascular a history of liver failure. The skin is also inspected for jaun- The Paramedic should inspect the patient for an elevated dice, a yellowish hue of the skin, which can indicate liver jugular venous pressure and the presence of peripheral failure or obstruction of the bile duct (Figure 16-31). Ecchy- edema. These may indicate a cardiac cause for shortness mosis, or bruising, may also be present in several locations on of breath. The Paramedic then auscultates the heart sounds the abdomen, including the umbilicus, the fl anks, or across for the presence of additional heart sounds and murmurs. the lower abdomen, and can indicate internal bleeding from These may also indicate a cardiac cause for the shortness of either a medical condition or traumatic injury. breath. Finally, the Paramedic assesses the peripheral pulses The bowels produce sounds from the rhythmic movement and capillary refi ll to determine the patient’s perfusion. Poor of material through the gastrointestinal tract. These sounds can perfusion with a lack of oxygen to the body’s organs can be auscultated by the Paramedic and may provide some clue produce the sensation of shortness of breath without respi- as to the cause of the patient’s abdominal pain. Bowel sounds ratory disease. are generally softer pitched gurgling sounds as compared to lung sounds and may be diffi cult to hear in the prehospital Neurovascular environment.44 In order to declare bowel sounds completely absent, the Paramedic would be required to listen for sounds The Paramedic assesses the patient’s mental status to determine for approximately three minutes, which is not realistic in the level of alertness. As respiratory distress worsens and the the prehospital environment. High-pitched, loud sounds that patient becomes |
tired, the patient’s mental status will begin to sound like water dripping may indicate a bowel obstruction. decline.43 This can result from lack of energy, but also may be The Paramedic can also assess the abdomen using per- due to the buildup of the blood’s carbon dioxide (CO ) level. 2 cussion. The percussion note over the liver and spleen, which Patients in respiratory distress use more energy to breathe, are solid organs, should be dull. The percussion note over thus producing more CO . As the level of distress increases, 2 other parts of the abdomen should be a normal sound similar the ventilation becomes poorer and the patient is not able to to that of the lung. If the abdomen is distended, a percus- exhale the CO that is produced. The CO levels increase in the 2 2 sion note can help differentiate between a fl uid-fi lled abdo- blood. When the CO levels become high enough, the patient’s 2 men and an air-fi lled abdomen. If the distended abdomen is respiratory drive and mental status is further depressed, again distended with ascites, or fl uid, the percussion note will be impairing the patient’s ability to remove the CO from the 2 dull. If the distended abdomen is fi lled with air, as in the case blood. This cycle continues until the patient becomes uncon- of a bowel obstruction, then a tympanic percussion note will scious and develops respiratory arrest. Patients with a chief be heard. Tenderness with percussion over a portion of the concern of shortness of breath who have an altered mental abdomen may indicate irritation of the peritoneum, the inner status require aggressive airway management and ventilatory lining of the abdomen. Irritation of the peritoneum can occur support in order to halt this dangerous cycle. with infection, infl ammation, or blood in the peritoneal cav- ity. Finally, costovertebral angle tenderness, also known as Put It All Together CVA tenderness, can indicate kidney irritation from a kid- The assessment of a patient presenting with the chief con- ney stone or infection. The costovertebral angle is located cern of shortness of breath includes many possibilities over the lower ribs just medial to the posterior axillary line (Figure 16-29). (Figure 16-32). Physical Examination and Secondary Assessment 279 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Mental status Cyanosis Jugular venous pressure (JVP) Lung auscultation Tracheal position Tactile fremitus Heart Percussion auscultation Radial pulse Pedal pulse Peripheral edema Figure 16-29 Assessment of a patient with the chief concern of shortness of breath. Figure 16-30 Abdominal distention. (Courtesy of Figure 16-31 Jaundice of the skin and scleral Michael English, M.D./Custom Medical Stock Photo) icterus. 280 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. during palpation and may indicate irritation of the perito- neum. Rovsing’s sign is pain in the right lower quadrant that occurs when the left lower quadrant is palpated, and is often associated with appendicitis. Murphy’s sign is right upper quadrant tenderness that worsens when the patient takes a deep breath while the quadrant is palpated and may indicate gallbladder infl ammation. In addition to looking for tenderness, the abdomen is pal- pated to detect masses. An abdominal mass is a general term used to describe an abnormally fi rm area of the abdomen. Masses can be tender or nontender, fi rm or soft, or pulsatile. Figure 16-32 Percussion of the costovertebral Pulsatile masses in the setting of hypotension raise concern for angle. vascular rupture of the abdominal aorta. Protrusions through the patient’s midline are likely related to a ventral hernia. Two different methods are used to divide the abdomen. Cardiovascular One method utilizes quadrants and the other method uses A limited cardiovascular examination is performed in patients “nines.” Quadrants are made by running both an imaginary with a chief concern of abdominal pain. For patients who have vertical line and an imaginary horizontal line through the epigastric pain, the Paramedic should be diligent and perform umbilicus (Figure 16-33a) such that there are four quad- a more extensive cardiovascular examination.45 rants. Nines are made by dividing the abdomen into three Inspect the patient’s skin for color and perfusion. Aus- horizontal sections and three vertical sections, similar to a cultate the heart for heart tones and murmurs. Palpate the tic-tac-toe board (Figure 16-33b) such that there are nine extremities for equality of the pulses, especially in the lower sections. Either method is acceptable. When the abdomen is extremities that may indicate a vascular problem with the divided up into quadrants, fi ndings correspond to the quad- abdominal aorta. When the abdomen is palpated, also assess rant where the fi nding was discovered. The Paramedic should the patient for hepatojugular refl ux. decide which method to use and stick with it. Each section should be palpated at least one time by applying gentle, but Put It All Together fi rm pressure with one hand while the other hand lies on top The assessment of a patient presenting with the chief and helps guide the fi rst. Rebound tenderness is tenderness concern of abdominal pain includes many possibilities that becomes worse when the pressure is suddenly released (Figure 16-34). Figure 16-33 Abdominal territories. (a) Quadrants. (b) Nines. Physical Examination and Secondary Assessment 281 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Costovertebral Jugular venous Skin color angle (CVA) pressure (JVP) percussion Ecchymosis Hepatojugular reflux Heart ausculation Abdominal Abdominal distension percussion Abdominal auscultation Radial pulses Abdominal palpation Femoral pulses Pedal pulse Figure 16-34 Assessment of a patient with the chief concern of abdominal pain. Syncope (place), and time. She also assesses the patient’s memory Syncope is a transient loss of consciousness that resolves spon- for the events leading up to the call for assistance. Amnesia taneously. Near syncope is the feeling that one is going to pass to the events can indicate a trauma patient sustained a head out, although one does not actually lose consciousness. Though injury. The Paramedic then assesses the patient’s attention by these are two separate conditions, both are treated the same observing whether the patient follows the conversation or is in regard to assessment and treatment. While there are many easily distracted. Next, the Paramedic assesses the patient for causes of syncope—ranging from benign to life-threatening— appropriate language. Do the sentences make sense? Is the the Paramedic should focus her examination on the more life- speech garbled or clear? Are the responses to questions in the threatening ones. Following is the physical examination of a proper context? patient with a chief concern of syncope or near syncope. The remainder of the neurological exam is divided up into the cranial nerve exam, the peripheral nerve exam, assessment Neurological of deep tendon refl exes, and assessment of coordination. The The neurological exam begins with assessing the patient’s cranial nerves are a set of 12 paired nerves that begin within mental status. The Paramedic assesses the patient for respon- the brainstem and are responsible for movement and sensation siveness, alertness, and orientation to self (person), location in the head and neck. The fi rst cranial nerve provides the sense 282 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. assessed by asking the patient to stick out his tongue and say “ah.” The tongue should protrude in the midline, and the soft palate near the pharynx should elevate symmetrically. The last part of the cranial nerve examination is to ask the patient to shrug his shoulders while observing for symmetry, which tests the eleventh cranial nerve. Peripheral sensation of the skin is organized into dermatomes that correspond to the spinal nerve roots ( Figure 16-36). The trunk can be rapidly assessed by running one fi nger down each side of the thorax, looking for equality of sensation. Lack of sensation below the same level on both sides of the trunk may indicate a spinal cord injury. A similar method can be used to assess sensation in the extremities. A difference in sensation between the extremities may indicate nerve root compression, a stroke, or damage to the peripheral nerve itself. Figure 16-35 Examination of the eyes for The deep tendon refl exes (DTRs) are tested by tapping a extraocular movements. large tendon and looking for involuntary muscle contraction in the muscle associated with that tendon. The biceps ten- don DTR is tested by supporting the patient’s fl exed forearm of smell, which is diffi cult to assess in the prehospital environ- and tapping over the biceps tendon in the antecubital fossa ment. The second cranial nerve is examined by assessing the (Figure 16-37a). The arm should quickly fl ex in response to patient’s visual acuity. This can be as simple as asking him to tapping the tendon. The patellar tendon DTR is tested by fl ex- read something printed and held at a normal reading distance ing the patient’s knee and allowing it to hang unsupported or assessing the visual acuity through a Snellen eye chart. with the patient is seated. The patellar tendon is tapped just Light perception is the ability to see light only. If the patient below the patella (Figure 16-37b). The knee should quickly has enough vision only to count the number of fi ngers held up extend in response to the tap. The plantar refl ex is assessed by in front of the eye, the visual acuity is measured as counting running a blunt object along the sole of the foot and observing fi ngers. The third, fourth, and sixth cranial nerves are assessed by examining the patient’s extraocular movements (EOM). Ask the patient to look at a fi nger, pencil, or the unlit penlight and follow that object with just his eyes. Make an H in the air C-2 and watch the patient’s eyes (Figure 16-35). If there is nor- C-2 mal EOM (sometimes documented as EOM intact or EOMI), the eyes will follow the object smoothly and with full range C-2 of motion. Abnormalities may include unequal movement or C-3 C-3 C-4 C-4 oscillating movements at the end of the excursion. These oscil- T-2 C-5 T-2 C-5 T-3 T-3 C-6 lating movements are termed nystagmus. A few beats of nys- T-4 T-4 T-2 T-5 T-2 T-5 tagmus are normal. Sustained or prolonged nystagmus may be T-6 C-6 T-6 T-7 a sign of intoxication or central nervous system problems. The T-7 T-8 T-8 T-9 C-8 C-7 third cranial nerve also controls the pupillary response, which C-7 T-9 T-10 T-11 T-10 T-12 is assessed by shining a penlight into the patient’s pupils one T-11 L-1 T-1 T-12 L-2 T-1 at a time, looking for constriction of both pupils. L-2 S-3 C-8 L-1 S-5 Sensation and motor function to the face are carried by S-4 S-3 the fi fth and seventh cranial nerves, respectively. Sensory L-2 Umbilicus S-2 function is assessed by touching the |
forehead, cheeks, and L-3 lower jaw on the left and right side of the face and looking for L-3 equality of sensation. Motor function is assessed by looking for symmetry of certain actions. The Paramedic should ask L-5 L-4 the patient to smile and then look for a symmetrical smile. L-4 The patient should be asked to open his eyes as wide as he L-5 can while the Paramedic looks for symmetry in the wrinkles in the forehead. The patient should also be asked to close his S-1 eyes as hard as he can, as the Paramedic looks for symmetry. S-1 The eighth cranial nerve is examined by assessing the patient’s hearing. The ninth and twelfth cranial nerves are Figure 16-36 Dermatomes. Physical Examination and Secondary Assessment 283 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. (a) (b) (c) Figure 16-37 Testing deep tendon refl exes. (a) Biceps. (b) Patella. (c) Plantar. toe movement (Figure 16-37c). In a normal response, the toes Cardiovascular fl ex and move downward. An abnormal response is when the Auscultate the heart sounds for tone, murmurs, and extra great toe pulls upward and the other toes fan out, indicating heart sounds that may provide a clue as to the reason for syn- spinal cord injury or a problem with the brain. cope. Loud or harsh murmurs that are new may indicate valve The fi nal portion of the neurological examination tests scarring or papillary muscle rupture that may contribute to the patient’s coordination. Pronator drift is tested by asking the patient’s chief concern.46,47 The papillary muscles stabi- the seated patient to hold her arms out with the palms fac- lize, open, and close the valve leafl ets with each myocardial ing the ceiling and then close her eyes (Figure 16-38a). The contraction. The carotid arteries are auscultated to assess test is positive if one arm drifts away from the starting posi- for carotid bruits. A bruit is a whooshing sound heard in a tion. The arm that drifts also tends to begin to rotate toward blood vessel that has plaque buildup on the vessel walls. This a palm-down position. Coordination is also tested by asking buildup causes turbulent blood fl ow. The Paramedic places the patient to touch her nose with one pointer fi nger and then the bell of the stethoscope over the carotid artery on one side to touch the Paramedic’s fi nger and move back and forth sev- of the neck and asks the patient to take in and hold a deep eral times (Figure 16-38b). This is repeated with the opposite breath. The Paramedic then listens for the bruit. If a bruit is hand. The lower extremities can be tested by asking the semi- present, it may indicate atherosclerosis in the carotid artery reclined patient to touch the heel of one leg to the opposite that puts the patient at risk for a stroke. leg just below the knee and slide it down the tibia (Figure Pulses are palpated for strength and equality. Weak or 16-38c). Abnormalities in coordination often indicate a prob- absent peripheral pulses may indicate hypotension as a lem in the cerebellum, the portion of the brain responsible cause of syncope. Unequal pulses may indicate a vascular for balance. 284 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. (a) (b) (c) Figure 16-38 Coordination testing: (a) Pronator drift. (b) Finger to nose. (c) Heel to shin. problem as a cause of the patient’s syncope. Perfusion is also and dorsifl ex the feet (Figures 16-40a and 16-40b) against assessed using capillary refi ll and strength of the pulses in the resistance. If the patient is lying or reclined, the Paramedic extremities. tests proximal muscle strength by asking her to lift her leg Finally, orthostatic vital signs may be helpful in assess- against resistance. If the patient is seated, the Paramedic tests ing for hypovolemia that is not present with the resting vital proximal muscle strength by asking the patient to lift or raise signs. Care should be taken when positioning the patient in a her fl exed knee against resistance (Figure 16-40c). Unequal standing position so the patient does not fall and injure her- muscle strength may indicate stroke, injury to the extremity self a second time. muscles, or a spinal cord problem. The bony surfaces of the upper and lower extremities are Musculoskeletal palpated for tenderness with special attention to the joints The goal of the musculoskeletal examination is to assess for and areas that the patient complained were painful during weakness and detect injury sustained during the syncopal the interview. Assess the stability of straight extremities by episode. The Paramedic examines any painful areas closely placing opposing forces over the bony surfaces and the joints for injury using palpation and inspection. Muscle strength of (Figure 16-41). Angulated extremities where the long bone the upper extremities is tested by asking the patient to grip is obviously fractured and displaced at an abnormal angle the Paramedic’s fi nger (Figure 16-39a). The proximal portion should not be stressed (Figure 16-42). In patients who have of the upper extremities is tested by asking the patient to fl ex sustained an injury, palpate the patient’s spine along the bony her elbows against resistance (Figure 16-39b). Lower extrem- prominences in the midline while maintaining spinal motion ity muscle strength is also tested distally and proximally. restriction to assess for tenderness that may suggest a spinal Distally, the Paramedic asks the patient to both plantarfl ex fracture. Physical Examination and Secondary Assessment 285 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. (b) (a) Figure 16-39 Upper extremity motor examination. (a) Grip strength. (b) Elbow strength. (a) (c) (b) Figure 16-40 Lower extremity motor examination. (a) Plantarfl exion against resistance. (b) Dorsifl exion against resistance. (c) Proximal lower extremity muscle strength examination. 286 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Figure 16-41 Applying oppositional forces over an extremity to test stability. Figure 16-42 Example of an angulated extremity fracture. (Courtesy of Deborah Funk, MD, Albany Medical Center, Albany, NY) If the patient is ambulatory at the scene, the Paramedic should observe the patient’s gait, or the way the patient walks, common causes of altered mental status and is immediately for abnormalities. Normally, a steady gait appears balanced treatable by the Paramedic. The Paramedic’s goal in assessing with the feet approximately shoulder width apart and fl ows the patient with altered mental status is to identify reversible smoothly as the patient ambulates. A multitude of gait dis- causes while providing supportive care to the patient. turbances are possible. It is best to describe and document what you see. The patient may stagger or appear off balance. Neurological The patient’s feet may be spread far apart. The gait may not be smooth or may include additional movements. If the The objective of the neurological exam in a patient with a patient is ambulatory, then the Paramedic should comment chief concern of altered mental status is to identify signs of a focal neurological issue.48–50 on the patient’s gait. If he decides to ambulate a patient who For example, unequal motor is not already ambulating, he should do so with care that the strength or unequal sensation may indicate a localized dis- patient does not fall, causing further injury, or worsening ruption in brain function, which may be caused by a stroke the medical condition related to the chief concern. The Para- or a cerebral hemorrhage. A focal neurological issue differs medic should follow the service policies as some services from a condition that causes a global disruption such as low do not ambulate patients who are not already ambulating at or high blood sugar or fever. The exam is carried out as pre- the scene. viously described. Some components of the exam may be diffi cult to perform if the patient is not able to follow the Paramedic’s commands. Put It All Together The assessment of a patient presenting with the chief concern Cardiovascular of syncope includes many possibilities (Figure 16-43). The objective of the cardiovascular examination in a patient with a chief concern of altered mental status is to identify Altered Mental Status issues with perfusion that can lead to altered mental status. A rapid method of assessing perfusion is to palpate the periph- “Altered mental status” is a phrase used to describe any change eral pulses for strength and check the capillary refi ll in a hand from a normal mental status. This may range from “feeling or foot. The Paramedic should auscultate the heart for new fuzzy” or mild “confusion” up to complete loss of conscious- murmurs. An irregular heartbeat may indicate atrial fi brilla- ness. The number of causes of altered mental status varies tion, a rhythm that is associated with stroke, another potential widely, with some causes being the result of aging, infection, cause of altered mental status. intoxication, toxic substances, or hypoxia. The chief concern of altered mental status is often provided by family members, bystanders, or other individuals as the patient may not even be Respiratory able to express this as a chief concern. Often at the extremes The objective of the respiratory system examination is to of age—the elderly and the very young—fever is a cause detect respiratory conditions that can cause altered men- of altered mental status. Hypoglycemia is one of the most tal status, most commonly hypoxia and pneumonia. As Physical Examination and Secondary Assessment 287 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Mental status examination Mentation Romberg/pronator drift Cranial nerve examination Heart auscultation Carotid arteries Peripheral Extremity nerve palpation Biceps DTR sensory (all four) examination Radial pulses Upper extremity motor Patella DTR Gait and balance Lower extremity motor Pedal pulses Plantar DTR Figure 16-43 Assessment of a patient with the chief concern of syncope. discussed before, a buildup in the level of carbon dioxide in the blood will cause sleepiness and altered conscious- Skin ness. The Paramedic should assess the patient’s respira- The skin is assessed for color, condition, and temperature, all tory rate and effort, observing for signs of increased work features that may indicate infection, fever, or dehydration as of breathing, poor ventilation, and respiratory failure. She a cause of altered mental status. In bedbound patients, includ- should also assess the lung sounds for abnormal sounds that ing patients with paraplegia or past strokes with an inabil- may indicate a cause of respiratory distress. Measurement ity to ambulate, |
decubitus ulcers (also known as pressure of the patient’s pulse oximetry will provide an indication of ulcers) can form and become another source of infection. hypoxemia. Percussion of the chest may help detect signs of Skin that is cyanotic indicates severe hypoxemia requiring pneumothorax or pneumonia. immediate ventilatory support by the Paramedic. Ecchymosis, 288 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. lacerations, or abrasions indicate trauma and suggest a trau- table, and a penny). Then, continuing the examination a few matic cause for the altered mental status. minutes later, the Paramedic asks the patient to repeat back those three objects. The patient’s language and knowledge is examined as previously described. Abnormalities in the Psychiatric patient’s mood and affect may also indicate a psychiatric ori- Psychiatric conditions or worsening dementia can also cause gin for his altered mental status. A fl at affect occurs when an altered mental status. The fi rst episode of a psychiatric dis- the patient’s face is absent of an expression. Mood can be order may present with altered mental status. Patients with described as depressed, elated, or normal. a history of a psychiatric disorder may present with altered mental status if they decompensate, either through a worsen- Put It All Together ing of their chronic disease or through noncompliance with The assessment of a patient presenting with the chief con- taking their medications. Components of the psychiatric exam cern of altered mental status includes many possibilities include assessment of speech, thought processes, suicidal or (Figure 16-44). homicidal ideation, judgment, insight into medical condition, and mental status. Much of this examination is required to Extremity Pain ensure a patient who wishes to refuse medical attention has suffi cient capacity (i.e., mental ability) to understand the Extremity pain as a chief concern can have a traumatic origin potential medical condition and the consequences of refusing or a medical origin. The most common cause of extremity treatment or transport. pain is an injury. In order to assist in determining the cause, The Paramedic should listen to the patient’s speech. the pain should be localized to a particular joint, muscle, or Abnormal speech may be either fast or very slow compared bony landmark. to a normal rate. Pressured speech occurs when the patient Musculoskeletal is speaking so fast it appears she has an urgency or pressure to speak quickly. The volume of speech may be decreased The painful extremity should be inspected for signs of an in a patient who is depressed, while it may be signifi cantly obvious injury, including a laceration, abrasion, ecchymosis, increased in a patient exhibiting pressured speech. The speech or edema that can indicate an underlying bone injury. Inspec- may not be understandable in a patient with an altered mental tion may indicate signs of an obvious fracture or disloca- status. For example, a patient may mumble or only grunt in tion, including angulation of that extremity. The Paramedic response to questions or stimulus. should assess both the left and right extremities for edema. For the verbal patient, the Paramedic should assess the Bilateral, or both left and right, extremity edema tends to patient’s thought process. A normal thought process will indicate a systemic cause while unilateral, or one, extremity be clear, understandable, and logical. Abnormalities in the edema indicates a cause within that extremity. The extent of patient’s thought process include psychotic or paranoid the edema should be noted, as edema localized to a joint or thoughts and auditory or visual hallucinations. Patients with to a small area may indicate an underlying localized injury. hallucinations should be asked what they are seeing or what Extensive unilateral edema may indicate an acute problem the voices are telling the patient to do. All patients who with the blood supply to that extremity. The extremity should exhibit signs of depression should be asked about intent to also be palpated for stability as well as to help localize the harm themselves or others, as well as if they have a plan to pain. Edema is assessed for pitting, as discussed in the sec- carry out this suicidal or homicidal ideation.51 tion on focused cardiovascular examination for patients with Another component of the psychiatric examination a chief concern of chest pain (Figure 16-23). assesses the patient’s insight into the medical condition and Skin judgment, or ability to make reasonable decisions. Insight is an understanding of the patient’s current or chronic medical Skin color and temperature may also indicate the origin of condition, as well as the consequences of inappropriate treat- the patient’s extremity pain. Erythema, or redness in the skin, ment. An example of poor insight into one’s medical condition along with warmth may be an indication of cellulitis, or a is a patient who has insulin-dependent diabetes, packs up her skin infection. Erythema and warmth over a joint may indi- insulin when moving, then cannot fi nd her medications and cate an infection in the joint or an arthritis caused by infl am- waits several days until she is sick with an elevated glucose mation within the joint. Finally, abrasions, lacerations, and to call for an ambulance. A patient with good insight into her ecchymosis can indicate trauma to the extremity. condition would have kept medications separate in a known location so they could be accessed and taken as directed. Cardiovascular The mental status exam is often thought of only as an The Paramedic should palpate the peripheral pulse to ensure assessment of the patient’s orientation to person, place, it is present and the extremity is well perfused, especially and time; however, it involves several other components. in the situation of trauma to the extremity. He should check The patient’s memory is tested when the Paramedic asks the the pulse before and after splinting to detect overtightening patient to remember three distinct objects (e.g., an apple, a of the splint or loss of pulse from vessel damage during the Physical Examination and Secondary Assessment 289 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Mental status examination Cranial Psychiatric examination nerve Pupils examination Respiratory effort Skin color, Lung auscultation temperature, Cyanosis conditions Percussion note Ecchymosis Heart auscultation Extremity palpation (all four) Decubitus ulcers Dextrostick Upper extremity strength Gait and balance Lower extremity strength Figure 16-44 Assessment of a patient with the chief concern of altered mental status. splinting process. In patients with nontraumatic extremity High Blood Pressure pain and edema, the Paramedic should perform a cardiovas- cular examination to assess for signs of heart failure as the According to the American Heart Association, approximately cause of the patient’s chief concern. 72 million people in the United States are diagnosed with high blood pressure, with an even greater number of people Neurological unaware their blood pressure is high.52 Blood pressure can be The Paramedic should assess the painful extremity for sensa- elevated due to pain or the condition the patient is experienc- tion and motor function distal to the injury both before and ing. It is estimated that in the year 2004, hypertension caused after splinting. Sensation and motor function should also be approximately 54,000 deaths in the United States. High blood assessed in the situation of nontraumatic extremity pain. pressure is a signifi cant risk factor for kidney failure and heart disease, and a primary cause of stroke. Many patients do not Put It All Together exhibit symptoms for a long time prior to diagnosis. The assessment of a patient presenting with the chief concern The Paramedic’s goal in assessing patients with the of extremity pain includes many possibilities (Figure 16-45). chief concern of high blood pressure is to look for signs that 290 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Palpation of painful extremity Sensation Skin color, temperature Ecchymosis Edema (unilateral or bilateral) Distal pulses Motor function in affected extremity Figure 16-45 Assessment of a patient with the chief concern of extremity pain. the high blood pressure is causing organ damage, including palpate to determine the amount of fl uid present. Auscultate damage to the brain, heart, lungs, and kidneys. The major- the heart for murmurs or extra heart sounds that may indicate ity of patients encountered by the Paramedic do not require fl uid overload. He should palpate the peripheral pulses for acute lowering of their blood pressure in the prehospital equality and limb perfusion, and assess the blood pressure in environment. For patients who have a chief concern other both arms to detect a signifi cant difference that may indicate than high blood pressure, refer to the section of this chap- a problem with the aorta. ter that covers a focused examination related to that chief concern. Respiratory The Paramedic should inspect the patient for signs of Cardiovascular increased respiratory effort and work of breathing that indi- The cardiovascular examination focuses on detecting signs cate diffi culty breathing, as this may be related to heart fail- of heart failure. The Paramedic should inspect the patient ure or cardiac disease. The Paramedic should auscultate the for an elevated jugular venous pressure as well as peripheral lungs for rales or wheezes that may indicate fl uid in the lungs edema. If peripheral edema is present, the Paramedic should from heart failure. Physical Examination and Secondary Assessment 291 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Mental status Romberg/pronator drift Cranial nerve examination Jugular venous pressure (JVP) Lung auscultation Respiratory effort Heart auscultation Radial pulses Upper extremity motor strength Lower extremity motor strength Peripheral edema Pedal pulses Figure 16-46 Assessment of a patient with the chief concern of high blood pressure. Neurological HEENT The objective of the neurological examination is to assess for Patients may complain of a variety of chief concerns related defi cits that may be caused by a stroke or other brain event to the head, eyes, ears, nose, and throat, with the most com- that may be related to the high blood pressure. The Paramedic mon concern being pain. This may be associated with fever, should assess the patient’s cranial nerves and peripheral nerves vision changes, sore throat, foreign body sensation, or other for function. She should assess muscle strength and coordina- symptoms. In the setting of trauma, there is also a concern of tion for issues that are unilateral, as these may indicate a brain an underlying head injury. lesion. Altered mental status can result from severe hyperten- sion that disrupts the perfusion of blood to the brain. Head Assess the head for evidence of trauma, including abra- Put It All Together sions, lacerations, ecchymosis, and obvious deformities. For The assessment of a patient presenting with the chief con- patients with a chief concern of headaches or facial pain, the cern of high blood pressure includes many possibilities Paramedic should percuss the sinuses (Figure 16-47) to elicit (Figure 16-46). tenderness that may indicate a sinus infection. 292 Foundations |
of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. mucous membrane for a source of the bleeding in the anterior portion of the nare. In the setting of nasal trauma, a septal hematoma (Figure 16-52) is a fi nding that requires attention) at the emergency department to ensure permanent damage to the nasal cartilage does not occur. Discharge from the nose may indicate a viral or bacterial infection of the sinuses.53–55 Throat The examination of the throat is important with any patient who has a concern related to the upper airway, including those patients with neck trauma or a suspected allergic reaction. The throat is examined for erythema and exudates, whitish discharge on the mucous surface, of the posterior pharynx (Figure 16-53). Swelling in the pharynx may also indicate Figure 16-47 Percussion of the sinuses. an impending airway issue. The uvula typically hangs in the midline of the pharynx. Deviation of the uvula from the mid- line may indicate an abscess or hematoma that can poten- tially threaten the airway. The external aspects of the anterior neck and mandible are also assessed for edema that may indi- cate a potential airway issue. The oral mucous membranes are also examined for signs of dehydration. Normally, the mucous membranes should be pink and glisten with the usual amount of moisture in the mouth. Patients who are dehydrated will lose that glisten in the mucous membranes as less saliva is produced. In extreme dehydration, the lips will become chapped. Neurological The Paramedic should perform a cranial nerve examination to ensure proper function of the cranial nerves. Abnormali- ties in cranial nerve function can indicate an underlying brain Figure 16-48 Conjunctival erythema. (Courtesy of concern or compression of an individual cranial nerve. Custom Medical Stock Photo) Put It All Together The assessment of a patient presenting with the chief concern Eyes related to the head, eyes, ears, nose, or throat includes many The eyes are inspected for erythema on the conjunctiva that possibilities (Figure 16-54). indicates irritation of the eye (Figure 16-48). Pupillary reac- tion is tested for responsiveness and equality using a penlight. Fever If a foreign body sensation is present, or signs of irritation Fever is a common chief concern for both young and old, with exist, the eye is stained using fl uroescein to inspect for a for- the extremes of age more likely to develop sepsis, the infl am- eign body or corneal abrasion (Figure 16-49). matory response to a systemic infection, or septic shock, where the patient develops hypotension from the systemic Ears infection. Fever is also a common cause of altered mental The Paramedic should inspect the external ear for erythema, status, especially in the elderly. Altered consciousness or per- signs of trauma, discharge, or edema. She should palpate the sonality in the very young can also indicate a severe illness external ear for tenderness. Using an otoscope (Figure 16-50), that requires further evaluation at the emergency department. the Paramedic should inspect the ear canal and middle ear for While fever is most often caused by an infection, fever can erythema, discharge, fl uid behind the tympanic membrane, or also be caused by other conditions including toxic ingestion, signs of otitis media, a middle ear infection (Figure 16-51). environmental related illness, and disorders of a patient’s thermoregulatory system. Nose The nares, or nostrils, are inspected for erythema and edema Respiratory of the mucous membranes or turbinates If an epistaxis, or The respiratory exam focuses on searching for a cause of the nosebleed, is present, the Paramedic should inspect the fever, especially when combined with hypoxemia determined Physical Examination and Secondary Assessment 293 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. (c) (a) Uptake indicating abrasion (d) Foreign body (b) (e) Figure 16-49 Examination of the eye for foreign body or corneal abrasion. (a) Instill two drops of tetracaine into the eye to be examined. (b) After 30 to 60 seconds, apply the fl uorescein strip, asking the patient to blink several times. (c) Examine the eye under a Wood’s lamp or using the cobalt blue fi lter on an ophthalmoscope. Direct the patient to move through the full range of motion of the eye. (d) Uptake of the dye indicates a corneal abrasion. (e) Foreign body present on the cornea. (Photo (d) is Courtesy of SPL/Custom Medical Stock Photo, (e) Courtesy of Michael Friedburg, O.D.) 294 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Figure 16-50 Paramedic assessing the ear with Image not available due to copyright restrictions an otoscope. from the vital signs. The Paramedic should inspect the patient for signs of increased respiratory effort. He should auscultate the lungs for signs of focal consolidation that may indicate Figure 16-51 Appearance of the tympanic pneumonia. Auscultation may also reveal wheezing from membrane in a patient with a middle ear infection associated bronchospasm, or constriction of the smaller air (otitis media). (Courtesy of B. Welleschik; licensed under passages that sometimes accompanies a respiratory infection. the Creative Commons Attribution ShareAlike 2.5) A dull percussion note over one area of the chest may also indicate a pneumonia in that portion of the lung. Gastrointestinal A gastrointestinal source of the fever is often suggested in a patient who is vomiting or has diarrhea. The Paramedic should inspect the patient’s abdomen for distention and dis- coloration. She should auscultate the abdomen to assess the patient’s bowel sounds, and palpate the abdomen, assess- ing for tenderness starting with the quadrant or section furthest away from the area of pain. The Paramedic should also palpate for the signs of peritoneal irritation as previ- ously described. Tenderness to percussion over the abdomen Septal hematoma may also indicate peritoneal irritation. A dull percussion note indicates ascites that can be the source of infection. A Figure 16-52 Septal hematoma. tympanic percussion note can indicate bowel obstruction or Physical Examination and Secondary Assessment 295 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Head trauma Pupil Cranial nerve Extraoccular movement (EOM) examination Conjunctiva Otoscopic examination Sinus percussion Examination Oropharynx examination for foreign body redness, uvula, mucous membrane) Nasal examination Throat/neck hematoma Figure 16-54 Assessment of a patient with the chief concern of related to the head, eyes, ears, nose, or throat. rupture that may be the source of infection. Tenderness with Gynecological percussion of the costovertebral angle can indicate pyelone- A brief gynecological examination is indicated when immi- phritis, or an infection of the kidney as a possible source of nent delivery is considered. While maintaining privacy with a the fever. sheet or other covering, the Paramedic should briefl y inspect Skin the vaginal opening for the presence of bleeding or discharge. Crowning occurs as the infant’s head begins the passage into The skin is inspected for signs of infection. Cellulitis can the birth canal (Figure 16-56), indicating delivery will occur present with erythema over an area of the skin. Patients with within several minutes. a history of diabetes are more likely to develop cellulitis over The abdomen is palpated to assess for tenderness and the lower extremities.56,57 Streaking, also known as lymphan- signs of peritoneal irritation in the pregnant female patient gitis, is infl ammation of the lymphatic channels in the skin complaining of abdominal pain. The uterus can often be pal- and occurs when there is spread of an infection located distal pated as a fi rm mass in the midline of the lower abdomen. It is to the streaking. As discussed earlier, decubitus ulcers can fi rst detected at approximately 12 to 15 weeks of gestation and develop and become infected in patients who are bed or chair grows until almost reaching the costal margin of the lower ridden. Finally, assessing the skin turgor, or elasticity, can portion of the rib cage by full term. Contractions can also indicate dehydration.58 be detected by the Paramedic during palpation as the uterus tightens and constricts. Contractions are measured for dura- HEENT tion and timing. The duration contraction is the length of time Examine the oropharynx for signs of infection and dehydra- the uterus is contracted. The timing is measured as the number tion in patients who have a chief concern of fever. of minutes between the beginning of one contraction and the beginning of the next, to include both one cycle of uterine con- Put It All Together traction and relaxation. This information is often reported as The assessment of a patient presenting with the chief concern “contractions of one minute in duration, three minutes apart.” of fever includes many possibilities (Figure 16-55). Respiratory Pregnancy The Paramedic should inspect the patient for signs of increased respiratory effort. He should also auscultate the While most pregnancies are uneventful, at times the Para- lungs for abnormal sounds (e.g., wheezes and rales). Signifi - medic will care for patients who have, or potentially have, a cant rales in combination with lower extremity edema may chief concern related to their pregnancy. Some of the com- indicate issues with hypertension or heart failure that have mon concerns include vaginal bleeding, abdominal cramp- developed during pregnancy. ing or pain, trauma in pregnancy, or impending childbirth. Many chronic medical conditions (e.g., asthma or diabetes) Cardiovascular can worsen during pregnancy and may require more frequent The Paramedic should inspect the patient for increased jugu- medical care.59 Seizures can occur secondary to issues with lar venous pressure and signifi cant peripheral edema that may hypertension in pregnancy. indicate problems with hypertension or heart failure related to 296 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Mental status Temperature (tympanic Oropharynx examination or oral) (mucous membranes) Lung auscultation Skin color, condition, Percussion turgor Abdominal inspection (palpation, percussion) Costovertebral angle Decubitus (CVA) tenderness ulcer Streaking Cellulitis Figure 16-55 Assessment of a patient with the chief concern of fever. pregnancy. Gallops and certain murmurs are normal in preg- response signifi cantly more brisk than normal, can indicate nancy as the blood volume increases and the growing fetus impending neurological issues. For pregnant patients treated compresses pelvic and abdominal blood vessels. However, with magnesium, one indication of too much magnesium is these conditions may be of concern in patients with a chief deep tendon refl exes that are hyporefl exive, or signifi cantly concern of chest pain or shortness of breath. The Paramedic less brisk than normal. should palpate the peripheral pulses or assess capillary refi ll to assess perfusion, then palpate the edematous extremities to Put It All Together assess the level of |
edema. The assessment of a patient presenting with the chief con- cern related to pregnancy includes many possibilities Neurological (Figure 16-57). Neurological issues during pregnancy are often related to the patient’s underlying seizure disorder or can be related to Trauma hypertension in pregnancy. In a pregnant patient with hyper- Trauma-related concerns are a signifi cant portion of the tension, the Paramedic should assess the deep tendon refl exes. requests for assistance encountered by Paramedics. The exam- Deep tendon refl exes that are hyperrefl exive, or produce a ination of patients who have sustained a suspected traumatic Physical Examination and Secondary Assessment 297 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Head Starting with the patient’s head, the Paramedic should inspect the scalp and face for lacerations, abrasions, ecchymosis, or obvious deformities that indicate the presence of a head injury. She should also inspect the mouth to assess for for- eign material and unstable or missing teeth that may occlude the airway if untreated. The Paramedic should palpate the skull and face to assess for stability of the bony structure. She should also assess pupil reaction and gross cranial nerve function to look for abnormalities that may indicate cerebral hemorrhage. Neck Figure 16-56 Crowning. While maintaining spinal motion restriction, the Paramedic should inspect the anterior neck for signs of trauma or edema injury follows a systematic head to toe approach after the pri- that may affect airway management or compromise the air- mary survey is completed to ensure detection of injuries based way. She should also palpate the trachea and larynx, assess- on the mechanism of injury. Even with a minor mechanism, the ing for stability, tenderness, and position of the trachea. The Paramedic needs to be thorough to ensure the presence of life- Paramedic should palpate the neck for subcutaneous emphy- threatening injuries is detected as early as possible. Prehospi- sema caused by a leak in the respiratory system, and palpate tal trauma triage guidelines have been developed to provide the cervical spine in the midline posteriorly, assessing for guidance to Paramedics in determining which patients should tenderness and deformity from a cervical spine injury. be transported directly to a trauma center and which patients can be cared for at a community hospital (Figure 16-58). Once Chest the primary survey is completed and any life-threatening The Paramedic should inspect the chest for respiratory effort, airway, breathing, or circulatory concerns are addressed, the abnormal chest wall movement, and signs of trauma, includ- Paramedic begins a more detailed head to toe examination. ing wounds and ecchymosis. He should also auscultate the Figure 16-57 Assessment of a patient with the chief concern related to pregnancy. 298 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. chest for the presence and equality of lung sounds in addi- tion to abnormal sounds. The Paramedic should palpate the chest for the presence of subcutaneous emphysema, for ten- derness, and instability. A fl ail segment develops when two or more adjacent ribs are fractured in two or more places (Figure 16-59). This produces an unstable area of the chest that impedes normal respiration. During inhalation, the fl ail segment is drawn inward by the negative pressure in the chest rather than expanding outward with the rest of the chest wall. During exhalation, the opposite occurs due to the increased pressure in the thorax during exhalation. This movement opposite of the normal chest wall movement is called para- doxical respiration. A hyperresonant percussion note can indicate a pneumothorax, where air is trapped between the pleural layers surrounding the lung, while a hyporesonant percussion note may indicate a hemothorax, or blood fi lling the space between the pleural layers. Abdomen The abdomen is inspected for wounds and other signs of direct trauma. Ecchymosis along either fl ank can indicate internal bleeding. A seat belt sign, or ecchymosis along the lower abdomen corresponding to the position of the lap belt, indicates enough force to produce internal damage.60–62 The Paramedic should note any distention present and palpate the abdomen for tenderness and fi rmness. Tenderness over the upper quadrants may indicate injury to the solid organs. A fi rm and distended abdomen is worrisome for internal bleed- ing that is not controllable in the prehospital environment. Pelvis The bony pelvis is assessed for stability and tenderness using palpation. After taking fi rm hold of the iliac wings (Fig- ure 16-60), the Paramedic gently applies pressure to com- press the pelvis. Tenderness may indicate a pelvic fracture, whereas instability is indicative of life-threatening internal pelvic bleeding and requires stabilization by the Paramedic. Extremities Finally, each extremity is inspected for obvious deformity, angulation, or wounds. The Paramedic should palpate each extremity for tenderness and stability (Figure 16-41). She should also palpate each extremity for the presence of a distal pulse or capillary refi ll to assess perfusion. The Paramedic should perform a rapid motor and sensory assessment on each extremity to ensure full function, then assess and docu- ment circulation, sensation, and motor function both before and after splinting injured extremities. Figure 16-58 National EMS trauma triage protocol. (Courtesy of Centers for Disease Control and Prevention, CDC) Physical Examination and Secondary Assessment 299 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Inspiration Expiration Flail section moves paradoxically (inward) Flail section moves paradoxically (outward) Figure 16-59 A fl ail segment paradoxically moves opposite the rest of the chest during inspiration and expiration. Spine The Paramedic should inspect the back for signs of lacera- tions, abrasions, and ecchymosis. He should palpate the spine for tenderness, stability, and alignment. This is often performed with the patient log-rolled to one side, main- taining spinal motion restriction (Figure 16-61) during the assessment. Any deformity or step off should be treated as a potential fracture with full immobilization and transport to an appropriate facility. Put It All Together The assessment of a patient presenting with the chief concern of major trauma includes many possibilities (Figure 16-62). Figure 16-60 Assessing the pelvis for stability. 300 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Figure 16-61 Assessment of the back and spine in a patient who was involved in a traumatic event. Primary survey: Focus on airway, breathing, circulation Secondary survey: Systematic head to toe approach after the primary survey is completed Scalp trauma Cranial Head nerve Pupils trauma/skull examination Face palpation Jugular venous stability pressure (JVP) Spine palpation Chest Tracheal position inspection: subcutaneous Lung emphysema, auscultation respiratory Tenderness effort, Heart and stability stability, auscultation spine percussion palpation Abdominal inspection, palpation Flank ecchymosis Pelvic stability Extremity examination (all extremities): palpation, distal circulation, motor, sensory Figure 16-62 Assessment of a patient with the chief concern of major trauma. Physical Examination and Secondary Assessment 301 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. While these common chief concerns will cover the majority of patients that the Paramedic will encounter, there will be some patients that do not have one of these chief concerns. By using these principles to perform a physical assessment, a Paramedic can perform an examination on patients in an effi cient manner which allows a full patient assessment. Key Points: • The four components to every physical exam are • The respiratory pattern or rhythm of the inspection, auscultation, palpation, and percussion. respirations is the combination of the timing of the respirations and the depth of respirations. • Inspection is a technique that involves looking at patients and their surroundings. • Blood pressure is the pressure within the arterial vessels of the circulatory system. • Auscultation of the patient is performed using a stethoscope. • The mean arterial pressure (MAP) is the average pressure in the arterial system over time while • Palpation is touch used to assess the stability of the pulse pressure is the difference between the bony structures and tenderness of muscle and systolic and diastolic pressures. tissue. • • The patient’s core temperature can be measured Percussion is lightly but sharply tapping the body from oral, rectal, or tympanic thermometers. surface to determine the characteristics (air-fi lled, fl uid-fi lled, or solid) of the underlying tissue. • Skin condition and color is an important indicator of perfusion. • Vital signs are objectively measured characteristics of basic body functions and include pulse, • Pulse oximetry is a noninvasive measurement of the respirations, blood pressure, and temperature. percentage of hemoglobin in arterial blood that is Assessment of a patient’s pain level and peripheral bound to oxygen molecules. oxygen saturation (SpO2) may also be included in the Paramedic’s assessment of vital signs. • Factors that may affect the accuracy of the pulse oximetry reading include poor blood fl ow due to • The pulse is assessed for rate, rhythm, and quality. hypovolemia or hypotension, and other compounds (e.g., carbon monoxide) that can also bind to • For patients with signifi cant tachycardia, 180 to hemoglobin and interfere with pulse oximeter 220 beats per minute, or infant and toddlers, the readings. Paramedic may use a stethoscope to listen to the heart and count an apical pulse. • The amount of exhaled carbon dioxide is related to the patient’s ability to move air in and out of the • Respirations are assessed by observing the lungs and is directly related to the patient’s level of respiratory rate, depth, pattern, and work of perfusion. breathing. • Orthostatic vital signs are signs that change when • Depth of respirations can be described as an individual changes position from lying down shallow (hypoventilation), normal, or deep to a standing position due to the heart’s inability (hyperventilation). 302 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. to compensate and maintain an adequate blood • The abdominal exam in a patient with a chief pressure and pulse. concern of chest pain is limited to palpation for pain and signs of fl uid overload. Positive hepatojugular • Positive orthostatic vital signs are defi ned as a heart refl ux is a sign of fl uid overload related to right- rate increase of 20 beats per minute or greater, sided heart failure. A normal mental status indicates a systolic |
blood pressure drop of greater than 20 that the brain is receiving a suffi cient amount of mmHg, a diastolic blood pressure increase of 10 oxygenated blood. An altered mental status, which mmHg, and/or dizziness or lightheadedness with may vary from confusion to unconsciousness, can position change. indicate that the brain is not receiving enough • A patient’s chief concern or chief complaint is used oxygenated blood. to focus the history and physical examination on Shortness of Breath specifi c body systems. • The physical exam for a patient with a chief Chest Pain concern of shortness of breath is similar to the • The inspection of a patient with the chief concern exam performed for chest pain and begins with of chest pain begins with the assessment of jugular the assessment of respiratory effort and cyanosis. venous pressure (JVP) and signs of peripheral edema. Deviation of the trachea is also assessed and is usually a late sign of conditions that can cause a • Auscultation of heart sounds proceeds shift of the heart and lungs to one side. systematically and should note the normal heart sounds (S1 and S2), potential extra sounds (S3 and • The Paramedic assesses the patient using S4), and abnormal heart sounds such as murmurs auscultation to identify normal and several and rubs. abnormal lung sounds that can indicate a respiratory cause of shortness of breath. Other lung sounds, • Palpate the chest for a thrill or cardiac heave. elevated venous blood pressures, and peripheral Assess a patient’s peripheral pulse for strength and edema may also indicate a cardiac cause of equality in the left and right extremities. shortness of breath. Peripheral pulses and capillary refi ll can be used to assess a patient’s level of • Indications of a patient’s respiratory effort include perfusion. use of accessory muscles, evidence of sternal or intercostal retractions, increased respiratory rate, • Patients in respiratory distress use more energy or tripod positioning. The patient’s skin, mucous to breathe; thus, they produce more CO2. As the membranes, and nail beds can be assessed for level of distress increases, the ventilation becomes cyanosis developed from hypoxemia. poorer and the patient is not able to exhale the CO2 that is produced. The CO2 levels increase in the • When auscultating lung sounds, the Paramedic blood. When the CO2 levels become high enough, should auscultate posteriorly and the left and the patient’s respiratory drive and mental status right sides of the chest, comparing the same levels are further depressed, again impairing the patient’s from apex to base. The Paramedic may be able ability to remove the CO2 from the blood. Patients to determine conditions associated with certain with a chief concern of shortness of breath who abnormal lung sounds (e.g., wheezing, which is have an altered mental status require aggressive associated with asthma or COPD). airway management and ventilatory support in order • Percussion of the chest may reveal normal hollow to halt this dangerous cycle. sounds, a hyperresonant note often seen with a Abdominal Pain pneumothorax, or hyporesonant notes that may indicate fl uid in the lung from either a pleural • The abdomen is inspected for distention and effusion or hemothorax. The Paramedic should prominent surface veins and the skin is inspected palpate the chest to assess the stability of the for jaundice or ecchymosis. Bowel sounds can be rib cage, tenderness, equal expansion, and the auscultated by the Paramedic and may provide some presence of subcutaneous emphysema. clue as to the cause of the patient’s abdominal Physical Examination and Secondary Assessment 303 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. pain. Percussion can also be used by the Paramedic fourth, and sixth cranial nerves are assessed by to assess the abdomen for ascites or fl uid, as well as examining the patient’s extraocular movements tenderness indicative of irritation of the kidney or (EOM). Sustained or prolonged nystagmus may be peritoneum. a sign of intoxication or a central nervous system problem. The third cranial nerve also controls the • The abdomen can be divided into either four papillary response, which is assessed by shining a quadrants or by a method of nines. Each section penlight into the patient’s pupils one at a time, found in either method is palpated by applying looking for constriction of both pupils. gentle, but fi rm pressure with one hand while the other hand lies on top and helps guide the fi rst. • Sensation and motor function impulses to the face Patients may demonstrate rebound tenderness are carried by the fi fth and seventh cranial nerves, or exhibit different signs associated with specifi c respectively, and are assessed by looking for any conditions. The abdomen is also palpated for any asymmetry in sensation or movement of the face. masses that can be tender or nontender, fi rm or The eighth cranial nerve is examined by assessing soft, or pulsatile. the patient’s hearing. Asking the patient to stick out his tongue and say “ah” assesses the ninth and • For patients who have epigastric pain, the Paramedic twelfth cranial nerves. The last part of the cranial should be diligent and perform a more extensive nerve examination is to ask the patient to shrug his cardiovascular examination. Skin color and perfusion shoulders while observing for symmetry, which tests should be inspected, accompanied by auscultation the eleventh cranial nerve. of heart tones and murmurs. The Paramedic should palpate for hepatojugular refl ux and assess the • Peripheral sensation of the skin is organized into extremities for equality of the pulses, especially in dermatomes that correspond to the spinal nerve the lower extremities. An inequality may indicate a roots. Differences in sensation between extremities vascular problem with the abdominal aorta. may indicate nerve root compression, a stroke, or Syncope damage to the peripheral nerve itself. Deep tendon refl exes (DTRs) are tested by tapping a large tendon • Syncope is a transient loss of consciousness that and looking for involuntary muscle contraction in resolves spontaneously. Near syncope is the feeling the muscle associated with that tendon. The bicep that one is going to pass out, although one does not tendon DTR and patellar tendon DTR, along with the actually lose consciousness. Assessment of syncope plantar refl ex, are refl exes that can be evaluated or near syncope begins with the determination of during an assessment. the patient’s level of responsiveness, alertness, and orientation to person, place, and time. It • The Paramedic can assess a patient’s coordination also assesses the patient’s memory for the events by testing the patient for pronator drift. Further leading up to the call for assistance and whether assessment of coordination can be carried out by the patient is able to pay attention or is easily asking the patient to touch her nose with one fi nger distracted in conversation. The patient should and then touch the Paramedic’s fi nger, or asking the exhibit appropriate language with clear speech and patient to touch the heel of one leg to the opposite respond to questions in an appropriate context. leg just below the knee and slide it down the tibia. • The remainder of the neurological exam is divided • The cardiovascular assessment for syncope or near up into the cranial nerve exam, the peripheral syncope involves auscultation of heart sounds for nerve exam, assessment of deep tendon refl exes, tone, murmurs, and extra heart sounds. Pulses should and assessment of coordination. The cranial nerves be palpated for strength and equality. Orthostatic are a set of 12 paired nerves that begin within the vital signs may help assess for hypovolemia that is brainstem and are responsible for movement and not present with the resting vital signs. sensation in the head and neck. • The musculoskeletal examination is used to assess • The second cranial nerve is evaluated through for weakness and detect injury sustained during the assessment of the patient’s visual acuity. The third, syncopal episode. The Paramedic should palpate 304 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. and inspect any areas that are painful while testing including a fracture or dislocation, laceration, the muscle strength of both the upper and lower abrasion, ecchymosis, or edema that can indicate extremities. Bony surfaces and joints should also an underlying bony injury. Erythema, or redness in be assessed for stability. The Paramedic should also the skin, along with warmth may be an indication of observe and document any abnormalities in the cellulitis, or a skin infection. patient’s gait. • The Paramedic should palpate the peripheral pulse Altered Mental Status of the extremity for adequate perfusion in a trauma situation. Assessment of sensation and motor function • Altered mental status can be described as any should be performed in situations of nontraumatic as change from a normal mental status. Some well as traumatic extremity pain. Sensation and motor causes of altered mental status can be aging, function distal to the injury should also be performed infection, intoxication, toxic substances, hypoxia, with a pulse check before and after splinting. hypoglycemia, or trauma. The Paramedic’s goal in assessing the patient with altered mental status High Blood Pressure is to identify reversible causes while providing supportive care to the patient. • The majority of patients encountered by the Paramedic do not require acute lowering of the • The objective of the neurological exam in a patient blood pressure in the prehospital environment. with a chief concern of altered mental status is to However, it is the Paramedic’s goal in assessing the identify signs of either a focal neurological issue, patient to look for signs that the high blood pressure such as a stroke or a cerebral hemorrhage, or a is causing organ damage, including damage to the global disruption, such as low blood sugar or fever. brain, heart, lungs, and kidneys. For the respiratory system examination, one of the most common causes of altered mental status is • The cardiovascular examination focuses on hypoxia. The Paramedic should again focus on the detecting signs of heart failure. The Paramedic patient’s ability to oxygenate and ventilate. should palpate for peripheral edema and pulses, auscultate for heart murmurs or extra heart sounds, • The assessment of skin color, condition, and and assess the patient’s blood pressure. temperature may indicate infection, fever, or dehydration as causes of altered mental status. • The Paramedic should auscultate lung sounds and Ecchymosis, lacerations, or abrasions indicate inspect the patient for signs of diffi culty breathing trauma and suggest a traumatic cause for the that may be related to heart failure or cardiac altered mental status. disease. Assessment of the cranial nerves and muscle strength and coordination may identify • Psychiatric conditions or worsening dementia can defi cits that may be caused by a stroke or other also cause an altered mental status. Components of brain event that may be related to high blood the psychiatric exam include assessment of speech, pressure. Severe hypertension that disrupts the thought processes, suicidal or homicidal ideation, perfusion of blood to the brain can result in the judgment, insight into medical condition, and mental patient presenting with altered mental status. status. Much of this examination is required to ensure a patient who wishes to refuse medical attention HEENT has suffi cient capacity (i.e., mental ability) to understand the potential medical condition and the • A variety of chief concerns are related to the head, consequences of refusing treatment or transport. eyes, ears, nose, and throat, with the most common concern being pain. The Paramedic should inspect Extremity Pain the head for evidence of trauma |
and the eyes for responsiveness to light, erythema on the conjunctiva, • Extremity pain as a chief concern can have a and signs of irritation or a foreign body present. traumatic origin or a medical origin. To determine the cause, the Paramedic should inspect the • Ears should be inspected for erythema, signs of painful extremity for signs of an obvious injury, trauma, and discharge or edema. The nares, or Physical Examination and Secondary Assessment 305 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. nostrils, are also inspected for erythema and edema. the presence of bleeding or discharge and evidence If an epistaxis is present, the Paramedic should of crowning. The abdomen is palpated to assess inspect the mucous membrane to fi nd a source of for tenderness and signs of peritoneal irritation. the bleeding in the anterior portion of the nare. Contractions may also be detected and should be measured for duration and timing. • The throat is examined by the Paramedic for erythema, exudates, swelling, and deviation of • Signifi cant rales in combination with lower the uvula from the midline of the pharynx. Oral extremity edema may indicate issues with mucous membranes are also examined for signs of hypertension or heart failure that have developed dehydration. during pregnancy. Signifi cant peripheral edema, increased jugular venous pressure, and chest pain or Fever shortness of breath may also indicate problems with • Fever is a common chief concern for both young hypertension or heart failure. and old, with the extremes of age more likely to • Neurological issues during pregnancy are often related develop sepsis, or septic shock. Fever is also a to the patient’s underlying seizure disorder or can be common cause of altered mental status, especially related to hypertension in pregnancy. For pregnant in the elderly, but fever may also be caused by patients treated with magnesium, one indication of toxic ingestion, environmental related illness, and too much magnesium is deep tendon refl exes that are disorders of the patient’s thermoregulatory system. hyporefl exive, or signifi cantly less brisk than normal. • The respiratory exam focuses on searching for Trauma a cause of fever. The Paramedic should inspect the patient for signs of diffi culty breathing, and • The examination of patients who have sustained auscultate lungs for signs of focal consolidation and a suspected traumatic injury follows a systematic constriction of the smaller airway passages. head to toe approach after the primary survey is completed to ensure detection of injuries based on • The Paramedic should have a high index of suspicion the mechanism of injury. Starting with the patient’s of a gastrointestinal source of fever with patients head, the Paramedic inspects the scalp and face who present with vomiting or diarrhea. Palpation for lacerations, abrasions, ecchymosis, or obvious of the abdomen should be performed to assess deformities that indicate the presence of a head pain, infl ammation, ascites, and the possibility of injury. Inspection of the skull, face, and mouth is pyelonephritis. performed along with evaluating pupil reaction and gross cranial nerve function. • Besides assessing the patient’s skin color and temperature, the skin should be inspected for • With proper spinal motion restriction in place, the signs of infection as well as skin turgor that can Paramedic should inspect the anterior neck for indicate dehydration. The oropharynx should also be signs of trauma or edema that may affect airway examined for signs of infection and dehydration. management or compromise. The cervical spine should be assessed for midline position and palpated Pregnancy for tenderness and deformity. • Some of the common concerns for a patient who is pregnant include vaginal bleeding, abdominal • Assessment of the chest for patients with a chief cramping or pain, trauma in pregnancy, or concern of trauma involves inspection of the impending childbirth. The patient may also have a chest for respiratory effort, abnormal chest wall history of medical conditions such as diabetes or movement, and signs of trauma. A fl ail segment hypertension, although she may also have developed develops when two or more adjacent ribs are these conditions as a result of her pregnancy. fractured in two or more places. This results in paradoxical respirations whereby the fl ail segment • A brief gynecological examination is indicated when moves opposite of the normal chest wall movement. imminent delivery is considered. It involves the Further inspection and auscultation may indicate a Paramedic briefl y inspecting the vaginal opening for pneumothorax or hemothorax. 306 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. • The abdomen is inspected by the Paramedic for and after splinting injured extremities. Each wounds and other signs of direct trauma such as extremity should be assessed for the presence ecchymosis and distention. Tenderness or fi rmness of a distal pulse, sensation, and motor function. upon palpation of the abdomen may indicate Inspection and palpation of the spine is often injury to solid organs or internal bleeding. Pressure performed with the patient log-rolled to one side applied to the iliac wings of the pelvis is performed with proper spinal motion restriction carried out. to assess the stability of the pelvis. Any deformity or step off should be treated as a potential fracture with full immobilization and • Assessment and documentation of circulation, transport to an appropriate facility. sensation, and motor function is performed before Review Questions: 1. You are called to the scene of a 55-year- he may have gotten a piece of metal in his eye old female with the chief concern of chest and his eye is in pain. How do you assess the eye pain. Describe the elements of the physical for a foreign body? examination that you will perform during your 4. You are called by the husband of a 32-year-old patient assessment. female patient who is obviously pregnant. The 2. During your patient examination, you fi nd patient has a chief concern of shortness of that she has tenderness to palpation of her breath with a history of asthma. During your abdomen. Describe what you should do. assessment, you fi nd she is also having severe, 3. You are called to a construction site to care for a crampy lower abdominal pain. What should 25-year-old male patient with eye pain. He states you do? Case Study Questions: Please refer to the Case Study at the beginning of the 3. Describe a situation in which the incorrect chapter and answer the questions below. treatment could actually worsen your patient’s 1. What are the four components of each physical condition. exam? 2. When examining a patient, what elements of a patient’s condition can you see? Hear? Feel? Detect by the return of sound? Physical Examination and Secondary Assessment 307 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. References: 1. 19. Singer AJ, Kahn SR, Thode HC, Jr., Hollander JE. Comparison Rock, M. Underexposed. The neglected art of the physical exam. of forearm and upper arm blood pressures. Prehosp Emerg Care. Jems. 2006;31(5):40, 42–43. 2. 1999;3(2):123–126. Dickinson ET, O’Connor RE, Krett RD. The impact of prehospital instant photography of motor vehicle crashes 20. Naqvi NH. A universal celebration: 100 years of Korotkoff on receiving physician perception. Prehosp Emerg Care. sounds, 1905–2005. Vesalius. 2005;11(2):59–60. 1997;1(2):76–79. 21. Shlyakhto E, Conrady A. Korotkoff sounds: what do we know 3. Scott LA, Brice JH, Baker CC, Shen P. An analysis of Paramedic about its discovery? J Hypertens. 2005;23(1):3–4. verbal reports to physicians in the emergency department trauma 22. Phillips DM. JCAHO pain management standards are unveiled. room. 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Clin pressure. Curr Cardiol Rep. 2002;4(6):463–467. North Am. 2007;91(4):ix, 537–552. 308 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. 38. Sinisalo J, Rapola J, Rossinen J, Kupari M. Simplifying 50. Kothari RU, Pancioli A, Liu T, Brott T, Broderick J. Cincinnati the estimation of jugular venous pressure. Am J Cardiol. Prehospital Stroke Scale: Reproducibility and validity. Ann 2007;100(12):1779–1781. Emerg Med. 1999;33(4):373–378. 39. Lima A, Bakker J. Noninvasive monitoring of peripheral 51. Bray JE, Martin J, Cooper G, Barger B, Bernard S, Bladin, perfusion. Intensive Care Med. 2005;31(10):1316–1326. C. Paramedic identifi cation of stroke: community validation 40. Sanchez LD, Ban KM, Bramwell K, Sakles JC, Davis D, Wolfe of the Melbourne ambulance stroke screen. Cerebrovasc Dis. R, et al. A 29-year-old man with subcutaneous emphysema of the 2005;20(1):28–33. neck following blunt trauma. Intern Emerg Med. 52. Ekker T. When hope is lost . . . dealing with the suicidal patient. 2007;2(1):50–52. Jems. 1991;16(11):64–67. 41. Pullen RL, Jr. Assessing for hepatojugular refl ux. Nursing. 53. Whelton PK, Beevers DG, Sonkodi S. Strategies for improve- 2006;36(2):28. ment of awareness, treatment and control of hypertension: 42. Mueller C, Frana B, Rodriguez D, Laule-Kilian K, Perruchoud results of a panel discussion. J Hum Hypertens. 2004;18(8): AP. Emergency diagnosis of congestive heart failure: impact of 563–565. signs and symptoms. Can J Cardiol. 2005;21(11):921–924. 54. 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Samoilenko MV, Magomedov MK, Shabalkin BV. Delayed traumatic mitral regurgitation after blunt chest trauma. Arteriosclerosis of the right gastro-omental artery. Kardiologiia. J Trauma. 1999;47(5):982–984. 1992;32(1):16–18. 49. Kothari R, Barsan W, Brott T, Broderick J, Ashbrock S. 62. Randhawa MP, Jr., Menzoian JO. Seat belt aorta. Ann Vasc Surg. Frequency and accuracy of prehospital diagnosis of acute stroke. 1990;4(4):370–377. Stroke. 1995;26(6):937–941. Physical Examination and Secondary Assessment 309 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. KEY CONCEPTS: Upon completion of this chapter, it is expected that the reader will understand these following concepts: • Paramedic approach to clinical decision making • Developing a Paramedic fi eld diagnosis • The importance of enveloping a mechanism of injury or nature of illness • Differentiating between emergent and urgent • Methods of improved clinical decision making Case Study: The Paramedics saw both patients approach the ambulances parked at the fi rst aid station at the county fair. Each patient had the same complaint—chest pain which was worse when they took a deep breath. In obtaining a brief history, they found that Joseph Gonterman, a tall lanky 19-year-old, had just developed the pain after some coughing. He had a history of simple pneumothoraxes and currently had normal vital signs and oxygen saturation. Guiseppe Ferrari, a 68-year-old with a history of chronic lung disease, had been ill for several days before the fair. Since his granddaughter was showing her prized calf, he had decided to come to the fair anyway. Now it was diffi cult for him to breathe and he felt a little faint. 310 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Clinical Decision Making and Teamwork 311 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. OVERVIEW The out-of-hospital environment is heavily infl uenced by factors that create an environment like no other where medicine is practiced. The spectrum of patient care in the out-of-hospital environment ranges from obvious critical life threats and potential life threats to non life-threatening presentations. Effective practice in this environment requires the gathering, evaluating, and synthesizing of a great deal of information. The Paramedic must apply independent decision-making skills to make judgments and work effectively under immense pressure. Protocols, standing orders, and patient care algorithms can greatly assist the Paramedic in decision making. This approach has limitations, however: (1) It only addresses “classic” patient presentations, (2) it does not speak to those patients with multiple disease etiologies or those requiring multiple treatment modalities, and (3) it promotes linear thinking or “cookbook medicine.” The components of critical thinking include concept formation, data formation, application of principle, evaluation, and refl ection on action. Clinical Decision Making A Paramedic’s diagnosis is based upon a collection of the patient’s signs and symptoms, called the symptom complex, Using a process of systematic analysis and critical think- obtained by the Paramedic during the history and physical ing, the Paramedic makes clinical decisions that will be exam. incorporated into a patient’s treatment plan. This process of The Paramedic then compares the patient’s symptom assessment and treatment planning is called clinical decision complex against her knowledge base of diseases, disor- making. ders, and syndromes to fi nd a similar grouping of signs and symptoms and matches the symptom patterns to derive a Medical Intelligence diagnosis. Using his intelligence (i.e., past experience and medical Ordinarily, a Paramedic is hard pressed to make a diagno- knowledge), the Paramedic takes a systematic approach to sis of a disease in the fi eld. Generally, a medical diagnosis of a investigating a problem and coming to a decision. This sys- disease is made after exhaustive medical tests lead a physician tematic approach to clinical decision making is called medi- to one irreducible conclusion which excludes all other possible cal intelligence. In essence, it is how Paramedics think. It conclusions. The physician arrives at this medical diagnosis as has been suggested that medical intelligence—the process of a result of a deductive process that eliminates, or rules out, all learning from experience and past practice and then coming other possible known explanations for the patient’s condition. to a decision—is what separates healthcare providers from Paramedics do not have the resources or the time to use the lay public. deductive logic in the fi eld. Paramedics instead rely on their Medical intelligence starts with information gather- faster, but less precise, inductive logic to make a diagnosis. ing. For the Paramedic, this means taking a patient history This diagnosis tends to be broad in its scope, and treatments and performing the physical exam. With the facts in hand, derived from the diagnosis tend to be palliative in nature the Paramedic compares the data against his own previous (i.e., providing supportive care and relief from suffering, experiences, anecdotal information, and formal medical rather than being curative). education.1–3 This is called the knowledge base. The Para- Therefore, whenever a Paramedic makes a tentative deci- medic then starts to form ideas about what is causing the sion, called a Paramedic fi eld diagnosis, it is a broad all- patient’s condition. encompassing conclusion. A Paramedic fi eld diagnosis is a This process of forming ideas, called concept forma- complaint-based conclusion about the nature of the illness tion, is based on inductive logic. Inductive logic begins with or injury. observations, such as the history and physical exam. The A Paramedic’s fi eld diagnosis generally identifi es a dis- facts are then incorporated with the knowledge base. Then order or a syndrome. A disorder is a physiological deviation the Paramedic reduces it all to a single theory, a hypothesis. from a normal homeostasis (e.g., hypoxia). A syndrome is a In the case of patient care, the hypothesis is the cause of the collection of symptoms that characterize a condition or state patient’s illness or the Paramedic’s diagnosis. (e.g., acute coronary syndrome). 312 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. When arriving on a potential trauma call, the Paramedic Street Smart uses his knowledge of kinematics, the study of motion, and the mechanism of injury to derive a predictable injury pattern.8–14 For example, a front-end motor vehicle collision Some Paramedics, when faced with a scarcity of would propel a patient forward against the windshield and information, will make a hasty fi eld diagnosis that is cause head and neck injuries. broad and overgeneralized. This imprecise diagnosis, The patient’s chief complaint, or concern, and the lack of a sometimes called a garbage can diagnosis, lends mechanism of injury helps establish the medical nature of a call. The Paramedic then goes about ascertaining the nature of the little direction to patient care. illness. The nature of the illness is the sum of the patient’s chief complaint, or concern, and the history of the present illness. When conditions prohibit a more intensive history and Urgent or Emergent physical, the Paramedic should elect to treat the patient with Early in the assessment process, the Paramedic makes a gen- supportive care based upon the chief concern.4–6 This is eral decision whether the patient is emergent (i.e., arising referred to as symptom-based care.7 The Paramedic should unexpectedly and in need of immediate medical attention) or then strive to obtain more clinical information when condi- urgent (i.e., not emergent and in need of further assessment tions improve. For example, a Paramedic confronted with a and evaluation before treatment is initiated). patient with air hunger should elect to treat the hypoxia fi rst This general assessment of the patient’s condition is and then proceed to provide |
rapid transport and perform fur- termed the initial impression. An initial fi eld impression ther assessment en route. is based on a myriad of factors such as patient presentation, environmental factors, gross observation, and resources on- The Method of Paramedic Practice scene. These factors assemble in the Paramedic’s mind to cre- ate a sense of emergency or urgency. Starting with the patient’s chief complaint, or concern, the Paramedic forms a cognitive map of the potential etiolo- gies of the chief concern. For example, if the patient’s chief concern is chest pain, that elicits thoughts of numerous conditions which could account for the chest pain, including Street Smart acute coronary syndrome, costracondritis, and pulmonary embolism, to name a few. A fi eld impression can be reduced to simply thinking The thought of each of these conditions, and their accom- panying symptom complex, is contained in the Paramedic’s whether the patient is sick or not sick. This initial mind as a script. A script can be thought of as an idea which fi eld impression (i.e., if the patient failed the “look has an associated symptom complex and an associated fi eld test”) is used to decide the tempo of the team’s diagnosis and treatment plan. activities. For example, when thinking of acute coronary syndrome, the Paramedic thinks of not only those signs and symptoms in the symptom complex which are coupled with the diagnosis of acute coronary syndrome (such as substernal chest pain, If the patient is emergent, then initial life-saving maneu- ST segment elevation, and so on), but the associated treat- vers during the primary assessment must be performed on- ments as well. scene. The patient is then rapidly moved to the ambulance for transportation to defi nitive care. Initial Impression If the patient is urgent then, after a primary assessment is Upon arrival at the patient’s side, the Paramedic must fi rst completed, a more detailed history and physical is performed. make a decision whether the call is medical or trauma in Some experienced Paramedics come to this decision nature. To make that decision, the Paramedic considers if very quickly. These master Paramedics use what is termed there is a mechanism of injury, suggesting trauma, or a Gestalt, a way of seeing a pattern in the patient observation nature of illness, suggesting the call is medical. as a whole. It is not obtained by a summation of symptoms In the case of trauma, the mechanism of injury can pro- but rather from patterns having been observed in similar situ- vide some valuable clues to underlying injuries. The mecha- ations in past practice and experience. nism of injury includes those forces (e.g., shearing or tearing) Following the general impression, the Paramedic pro- that create physical harm to the patient. ceeds with obtaining the history and performing a physical Certain mechanisms of injury have characteristic injuries examination in order to ascertain the symptom complex. that are associated with that mechanism. These characteristic Using a standardized approach, such as the mnemonic injuries are referred to as the predictable injury pattern. OPQRST, reveals the symptom complex. Clinical Decision Making and Teamwork 313 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Some findings, such as nausea or headache, are non- specific (i.e., not indicative of any one disease), and are Street Smart often common to all sick patients. These general find- ings of illness are often referred to as constitutional signs. While constitutional signs help to establish that Paramedics who routinely perform tests, such as blood the patient is not well and in need of supportive care, glucose analysis, without consideration of the meaning they do not assist the Paramedic toward reaching a clini- of the results may be practicing defensive medicine. cal decision. The practice of performing random tests in order to limit liability, or criticism from the medical director, rather than performing just those tests that benefi t the patient should not be encouraged. Professional Paramedic Savvy patients may inquire about the necessity of fi eld Differential Diagnosis tests. Questions will arise regarding the accuracy of After gathering the facts in the case (the symptom complex), the test and whether the test delays transportation. comparing that to similar symptom patterns, and recognizing The professional Paramedic knows how often the test the similarity, the Paramedic advances a fi eld diagnosis. On occasion, the Paramedic may be confl icted whether to gives a correct positive result (its sensitivity) but also state one fi eld diagnosis or another. In those cases, the Para- how often it fails to give a correct positive result (its medic should consider applying Ockham’s razor. Ockham’s specifi city). Paramedics must be able to describe the razor, simply stated, says that if all things are equal, the simplest solution tends to be the best one. In other words, common things time the procedure takes and how it will enhance occur commonly. While exotic diseases do exist, the probability overall care. is low that these diseases are involved. Tests Street Smart Owing to the urgent nature of a medical emergency, the Para- medic must choose those tests that have the greatest yield The saying goes “When one hears hoof beats think horses of information. A random test, such as obtaining a 12 lead not zebras.” While the physician is tasked with “ruling ECG, without conscious consideration of what the results might reveal is wasteful. Before implementing any test, the out” these diagnoses, the Paramedic should focus on the Paramedic should ask, “Will this test affect my decision mak- more common and predictable causes of illness. ing?” If the answer is no, or unknown, then the test may be a waste of time. Whenever a test is performed, the Paramedic should be When the Paramedic is faced with a situation in which aware of its specifi city and the sensitivity, the test’s predictive several plausible explanations for a disorder exist and the Para- value. medic cannot narrow the causes down to one disease or another, For example, when the 12 lead ECG machine analysis then the Paramedic should treat the patient aggressively. The states “acute myocardial infarction suspected” the Paramedic Paramedic should assume that the disorder which can harm the can have confi dence that the patient is having an acute myo- patient the most exists. For example, while epigastric discom- cardial infarction. In other words, the Paramedic can assume fort could be gastric esophageal refl ux disease, it might also be the machine is correct, based on research that has shown good connected to an inferior wall acute ischemic event.17,18 Keeping sensitivity (97% accurate in one study).15,16 the patient’s best interests in mind, the Paramedic should treat However, the Paramedic must also be skeptical of the the patient as if he were having an acute coronary event and results as well. The 12 lead ECG machine may lack specifi c- consider the possible cardiac origin for this discomfort. ity (i.e., the machine may not read “acute myocardial infarc- If the Paramedic errs in the fi eld and treats the patient tion suspected” when in fact one does exist). with GERD as a cardiac patient, then the patient will most Understanding the limitation of every machine or test, likely be no worse for the care. However, if the Paramedic the Paramedic should never rely on one test result to make a treats the cardiac patient for heartburn only, missing the clinical decision. Instead, the Paramedic should consider the potential for an acute coronary event, then the patient could entire patient presentation, coupled with the test results, to have a catastrophic event and the opportunity for timely inter- arrive at a fi eld diagnosis. vention may be lost. 314 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. decisions. Implicit with the use of guidelines is accountabil- Street Smart ity. Whenever guidelines are in use, the Paramedic must be willing to discuss and defend the clinical decisions. Every Paramedic should look forward to the opportunity The Paramedic’s treatment philosophy could be to defend a clinical decision. These conversations with fellow summed up with the saying “Hope for the best but Paramedics or the medical director permit the Paramedic the treat for the worst.” opportunity to improve clinical decision making. Emergency medicine is a dynamic fi eld that requires fl exibility in thought and a willingness to see a different point of view. The Paramedic must become a good clinical decision Paramedics who are unwilling to consider alternatives to maker. The Paramedic’s ability to take all of the clinical infor- patient care, other than the routine care, because it has always mation and separate out irrelevant information from critical been done this way, are experiencing paradigm blindness.19 data is important for clinical decision making. Prepared with Good clinical decision making depends on a willingness to a well-conceived fi eld diagnosis, the Paramedic can then pro- accept new ideas and to practice creative thinking in the fi eld ceed with a treatment plan. (i.e., thinking outside of the box). The greatest danger to any Paramedic’s clinical deci- Barriers to Effective Clinical sion making is fear. Whenever a Paramedic feels unsure, or even threatened, by a clinical situation, the response will Decision Making be an adrenaline surge. Adrenaline can help to sharpen the Paramedic’s senses, improving the patient assessment, but it Skill in good clinical decision making is a function of formal can also narrow the Paramedic’s focus. This narrow focus of education and practical experience. It is essential that gradu- attention (e.g., to a task) causes the Paramedic to miss see- ate Paramedics have a formal education which provides both ing the larger picture and therefore miss important clinical depth and breadth in achieving a comprehensive understand- information. ing of paramedicine. Paramedics should strive to see situations as challeng- However, the knowledge base of the Paramedic who ing, not threatening, and maintain a sense of control from graduated, even with highest honors, is soon outdated. Every within. This internal locus of control (i.e., the idea that one Paramedic must understand and accept the need for continu- has the ability to control the situation) gives the Paramedic ing education for competency assurance and professional a sense of control over the situation. This sense of control development. This attitude can be best summed up by the can translate to a feeling of confi dence and improved clinical Japanese idea of Kaizen, meaning continuous performance decision making. Others, seeing the confi dence evident in the improvement. Paramedic, tend to follow the Paramedic’s lead. Improved clinical decision making can also be obtained from practical experience with a master Paramedic. Mentors, experienced master Paramedics, accept graduate Paramedics Improved Clinical as their protégés to teach good clinical decision making. These mentors often depend on intuition when making decisions in Decision Making ambiguous or complex situations. This clinical intuition, borne The Paramedic’s best ally for clinical decision making is the of experience, can be described as understanding without ratio- patient. While the patient always has a right to make informed nale, as opposed to irrational guessing. Sharing intuition with decisions about patient care, shared decision making goes novice Paramedics permits the novice Paramedic to develop beyond consent and engages the patient in a conversation about expert judgment. clinical decision making whenever possible. The patient is seen With limited education, and even more limited experi- as not being dependent (a paternalistic view), but rather inter- ence, the novice Paramedic may resort to applying protocol- dependent with the Paramedic. In a shared decision-making driven care in every circumstance. Protocols are a set of model, the patient is consulted |
about clinical decisions. Pro- mandatory behaviors meant to be applied in specifi c clini- viding the patient with current information about his or her cal conditions. Protocols, almost by defi nition, assume that state of health and offering medically reasonable alternatives the one patient’s situation is the same or similar to another empowers both the patient and the Paramedic. patient’s condition in the same situation. Obtaining patient concordance, the process of shared In many cases this approach is acceptable, and has advan- decision making, includes a communication of risk, the tages in a time-sensitive emergency. However, some patients advantages of compliance, and a shared responsibility to do not fi t the prescribed clinical condition. That is, the patient report changes. Shared clinical decision making fosters does not fi t into the mold. openness and trust between the patient and the Paramedic. In In those cases, the Paramedic should view the protocols addition, shared clinical decision making decreases patient as a set of guidelines. Guidelines provide direction while per- dissatisfaction, even allowing the patient to decide to with- mitting use of knowledge and experience to shape clinical hold treatment until arrival at the hospital. Clinical Decision Making and Teamwork 315 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Illnesses are progressive. Watchful waiting while provid- Cultural / Regional differences ing supportive care can sometimes make a cloudy clinical picture clearer or may demonstrate the ineffectiveness of a particular treatment. This may lead the Paramedic to consider It should be noted that while younger and better other treatment pathways. educated patients prefer to share clinical decision This process of assessment, treatment, and then reas- making, cultural and ethnic differences may decrease sessment is consistent with the quality improvement cycle patient cooperation. This lack of cooperation should (plan–do–check–act). Attention to evaluation of treatments and then consideration of further interventions leads to higher not be viewed as resistance to care but rather as a quality of care. trust in the Paramedic’s decision. Disposition Treatment Paramedic care is the beginning of the continuum of care Paramedics typically start patient care with empiric therapy, which is continued in the emergency department, critical care treatment based on initial observations obtained during the units, rehabilitation fl oors, and homecare services. In many primary assessment. For example, a person with obvious cases, the Paramedic’s decision in the fi eld puts the patient diffi culty breathing may receive oxygen immediately. Such onto a treatment pathway. For example, the Paramedic’s fi eld treatments are considered basic life support. Though they diagnosis might activate a “cardiac team” at a center for inter- may be complex, such as intravenous therapy, they are not ventional cardiology, alert a critical care unit of an impend- intended to treat a specifi c disorder. Rather, they are intended ing arrival, and set about a cascade of events, all designed to to support the body (palliative care). return the patient to the best state of health possible.20–25 Key to this process is good clinical decision making. Evaluate Clinical decision making is a process of systematic anal- Some novice Paramedics are compelled to act either by train- ysis, using medical intelligence and critical thinking, aided ing or cultural infl uences within an organization. This action by input from the team, which in the end is the basis for a plan imperative (i.e., don’t just stand there, do something) is some- of care. It always has the patient’s best interests in mind. times ill advised and can lead to catastrophic events. 316 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. The Paramedic of the future is a thinking practitioner who essentially operates almost independently in the prehospital environment. By using the methods discussed in this chapter, the Paramedic can move away from blindly following protocols and toward a thinking, professional practitioner. Key Points: • “Medical intelligence” is a term used to describe • Before implementing any test, the Paramedic should the Paramedic’s systematic approach to clinical determine whether the test will affect the decision- decision making. making or treatment plan. • The symptom complex is compared to the • Before the test is performed, the Paramedic should Paramedic’s own knowledge base to determine if be aware of its specifi city and sensitivity. any familiar symptom patterns exist. • The idea of preparing or treating for the worst and • Gathering information and reducing it to a hoping for the best is one way the Paramedic can single theory is called inductive logic. The keep the patient’s best interests in mind while Paramedic uses this line of thinking to investigate developing an appropriate fi eld diagnosis and a problem and develop an appropriate treatment treatment plan. plan. • Skill in good clinical decision making is a function of • When presented with a chief complaint or formal education and practical experience. concern, the Paramedic should begin to develop a list of possible etiologies of the • Protocols should be viewed as a set of guidelines chief concern. This cognitive list is then that provide direction while permitting the associated with a fi eld diagnosis and treatment Paramedic to use knowledge and experience to plan. shape clinical decisions. • To determine whether an emergency call is medical • Good clinical decision making depends on a or trauma in nature, the Paramedic must consider willingness to accept new ideas and to practice either the mechanism of injury or the nature of creative thinking in the fi eld (i.e., thinking outside illness. of the box). • The initial impression of a patient is based on • An internal locus of control, or one’s sense of factors such as patient presentation, environmental control over a situation, can translate to a factors, and resources available. feeling of confi dence and improved clinical decision making. Shared decision making goes • The initial impression is used in conjunction with beyond consent and engages the patient in a the primary assessment to determine if the patient conversation about clinical decision making is emergent or urgent. whenever possible. • Some fi ndings, such as nausea or headache, are • Treatment may begin with empiric therapy, based referred to as constitutional signs because they on the initial assessment. Further interventions are nonspecifi c and are often common to all sick should be based on a reassessment of treatments patients. given. Clinical Decision Making and Teamwork 317 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Review Questions: 1. Explain the process of medical intelligence. 6. Explain the difference between protocols and 2. Defend the concept of Paramedic fi eld diagnosis. guidelines. 3. Explain mechanism of injury and its 7. List methods of improved clinical decision relationship to a predictable injury pattern. making. 4. Explain the difference between emergent and 8. Explain how identifying inaccurate fi eld urgent. diagnoses can lead to improved patient care. 5. List the barriers to effective clinical decision making. Case Study Questions: Please refer to the Case Study at the beginning of the 2. Are each of these patients suffering from a chapter and answer the questions below. trauma event or a medical one? Explain your 1. Name the symptom complex for Joseph answers. Gonterman. Name the symptom complex for 3. Do Mr. Gonterman and Mr. Ferrari have the Guiseppe Ferrari. same priority? Why or why not? References: 1. Glick TH. Evidence-guided education: patients’ outcome and stratifi cation strategies. Md Med J, Suppl. 1997;7(1)(Suppl): data should infl uence our teaching priorities. Acad Med. 79–84. 2005;80(2):147–151. 8. Eid HO, Abu-Zidan FM. Biomechanics of road traffi c 2. Kilminster SM, Jolly BC. Effective supervision in clinical practice collision injuries: a clinician’s perspective. Singapore Med J. settings: a literature review. Med Educ. 2000;34(10):827–840. 2007;48(7):693–700; quiz 700. 3. Dornan T, Littlewood S, Margolis SA, Scherpbier A, Spencer 9. Mackay M. Mechanisms of injury and biomechanics: vehicle J, Ypinazar V. How can experience in clinical and community design and crash performance. World J Surg. 1992;16(3):420–427. settings contribute to early medical education? A BEME 10. Green RN, German A, Nowak ES, Dalmotas D, Stewart DE. systematic review. Med Teach. 2006;28(1):3–18. Fatal injuries to restrained passenger car occupants in Canada: 4. Fleischer AB, Jr., Gardner EF, Feldman SR. Are patients’ chief crash modes and kinematics of injury. Accid Anal Prev. complaints generally specifi c to one organ system? Am J Manag 1994;26(2):207–214. Care. 2001;7(3):299–305. 11. Kumar S, Ferrari R, Narayan Y. Kinematic and 5. Rottman SJ, Schriger DL, Charlop G, Salas JH, Lee S. On-line electromyographic response to whiplash loading in low-velocity medical control versus protocol-based prehospital care. Ann whiplash impacts—a review. Clin Biomech (Bristol, Avon). Emerg Med. 1997;30(1):62–68. 2005;20(4):343–356. 6. Kothari R, Barsan W, Brott T, Broderick J, Ashbrock S. 12. Kumar S, Ferrari R, Narayan Y. The effect of trunk fl exion Frequency and accuracy of prehospital diagnosis of acute stroke. in healthy volunteers in rear whiplash-type impacts. Spine. Stroke. 1995;26(6):937–941. 2005;30(15):1742–1749. 7. MacDonald GS, Steiner SR. Emergency medical service 13. Mikhail JN. Side impact motor vehicular crashes: patterns of providers’ role in the early heart attack care program: prevention injury. Int J Trauma Nurs. 1995;1(3):64–69. 318 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. 14. Loo GT, Siegel JH, Dischinger PC, Rixen D, Burgess AR, Addis 21. Feldman JA, Brinsfi eld K, Bernard S, White D, Maciejko T. MD, et al. Airbag protection versus compartment intrusion effect Real-time Paramedic compared with blinded physician determines the pattern of injuries in multiple trauma motor identifi cation of ST-segment elevation myocardial infarction: vehicle crashes. J Trauma. 1996;41(6):935–951. results of an observational study. Am J Emerg Med. 15. Sekiguchi K, Kanda T, Osada M, Tsunoda Y, Kodajima N, 2005;23(4):443–448. Fukumura Y, et al. Comparative accuracy of automated computer 22. Strauss DG, Sprague PQ, Underhill K, Maynard C, Adams GL, analysis versus physicans in training in the interpretation of Kessenich A, et al. Paramedic transtelephonic communication to electrocardiograms. J Med. 1999;30(1-2):75–81. cardiologist of clinical and electrocardiographic assessment for 16. Willems JL, Abreu-Lima C, Arnaud P, van Bemmel JH, Brohet rapid reperfusion of ST-elevation myocardial infarction. C, Degani R, et al. The diagnostic performance of computer J Electrocardiol. 2007;40(3):265–270. programs for the interpretation of electrocardiograms. N Engl J 23. Adams GL, Campbell PT, Adams JM, Strauss DG, Wall Med. 1991;325(25):1767–1773. K, Patterson J, et al. Effectiveness of prehospital wireless 17. Sheps DS, Creed F, Clouse RE. Chest pain in patients with cardiac transmission of electrocardiograms to a cardiologist via and noncardiac disease. Psychosom Med. 2004;66(6):861–867. hand-held device for patients with acute myocardial infarction 18. Miller CD, Lindsell CJ, Khandelwal S, Chandra A, Pollack (from the Timely Intervention in Myocardial Emergency, CV, Tiffany BR, et al. Is the initial diagnostic impression of NorthEast Experience [TIME-NE]). Am J Cardiol. “noncardiac chest pain” adequate to exclude cardiac disease? Ann 2006;98(9):1160–1164. Emerg Med. 2004;44(6):565–574. 24. Wojner-Alexandrov AW, Alexandrov AV, Rodriguez D, 19. Camp R. Benchmarking: The Search for |
Industry Best Practices Persse D, Grotta JC. Houston Paramedic and emergency That Lead to Superior Performance. Portland: Productivity Press; stroke treatment and outcomes study (HoPSTO). Stroke. 2006. 2005;36(7):1512–1518. 20. Le May MR, Dionne R, Maloney J, Trickett J, Watpool I, Ruest 25. Qazi K, Kempf JA, Christopher NC, Gerson LW. Paramedic M, et al. Diagnostic performance and potential clinical impact of judgment of the need for trauma team activation for pediatric advanced care Paramedic interpretation of ST-segment elevation patients. Acad Emerg Med. 1998;5(10):1002–1007. myocardial infarction in the fi eld. Cjem. 2006;8(6): 401–407. Clinical Decision Making and Teamwork 319 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. KEY CONCEPTS: Upon completion of this chapter, it is expected that the reader will understand these following concepts: • Duality of EMS communications • A history of radio communications from ground to satellite • Breakdown of radio architectures, bandwidths, and technology • Phases of EMS communications, from the initial call for help to turning the care over to hospital staff • The standardized radio report for communicating with physicians Case Study: The Paramedic was the fi rst on-scene of a two-car motor vehicle collision with possible patient entrapment. A fi rst due report was relayed to the dispatcher and different members of the public safety team began to arrive. A fellow Paramedic took up EMS command and the Paramedic was directed to care for a critically ill trauma patient. After a primary assessment and treatment of life-threatening injuries, the patient was extricated and moved to an ambulance. While en route to the hospital, the Paramedic contacted medical control for advanced procedures and to initiate a trauma alert. 320 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Communications 321 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. OVERVIEW Communication can involve the exchange of ideas or interactions between two parties, as well as the technology that is behind sending and receiving information. Both of these aspects of communication are examined in this chapter. First, the chapter looks at the duality of EMS communications. A fundamental part of the Paramedic’s day-to-day operations involve interacting with fellow members of a public safety team as well as healthcare providers at hospital care facilities. Because the Paramedic relies on technology to perform these functions, the Paramedic should have an understanding of radio communications and the technology used in the prehospital setting. Communications and Teamwork Teamwork is an outward demonstration of the power of com- munication. Health care is a team activity; its goal is the patient’s health. Paramedics, in the prehospital phase, actu- ally play for two teams. The fi rst team is the public safety team, a triad made up of law enforcement offi cers (LEO), fi refi ghters (FF), and Paramedics. This team’s goal is to pro- vide for the public’s safety through control and command of public emergencies. As with any team, communication is essential. Communications are essential to maintain the threefold concerns of the rescuer’s safety, the public’s safety, and the patient’s safety as the Paramedics go about accom- plishing their mission. While Paramedics are part of the public safety team, Figure 18-1 A Paramedic giving a verbal report a Paramedic is also part of a healthcare team. Healthcare to a nurse. teams, ranging from primary care providers to rehabilita- tion services, are dedicated to helping the patient through a has both medical and legal importance.1–7 This chapter deals medical emergency. A Paramedic’s communication with the with the fi rst communication, verbal communication, while healthcare team serves the patient’s interests by providing the the next chapter deals with the second, written communica- patient’s past medical history, information about the history tion or documentation. of the patient’s present illness, and the patient’s response to Verbal communications is further divided into mobile prehospital treatment. The Paramedic’s communication with communications and face-to-face exchanges. Before discuss- the healthcare team also represents a hand-off of the patient, ing the fi rst, mobile communications, it is important to have or the transfer of care, from the prehospital team to the emer- a foundation in radio theory. gency department team. Communication occurs between team members within the team as well as with other teams. Instances of communica- History of Radio tion, called interfaces, occur in both oral and written forms, Since the fi rst radio transmission, from St. John’s, New- and take place at many times during the duration of the patient foundland, to Cornwall, England, the potential for com- contact. The fi rst interface may be between lay fi rst responders munication through radio has been ever growing. The early or emergency medical responders and the Paramedic. The next theorists, such as James Clark Maxwell, a Scottish physicist, interface may be between prehospital and emergency depart- hypothesized that an electrical or magnetic disturbance could ment personnel (Figure 18-1). In fact, there are often many spread across the “ether” (ether was invisible substance interfaces with other members of both the public safety team thought to fi ll space) like waves on the ocean from a distant and the healthcare team during the course of a patient’s care. storm. This theory was substantially correct. Electrical cur- For the sake of expediency, most of these c ommunications rent passing through a wire creates a fi eld of electromagnetic are either face-to-face or via a mobile communications energy around it as it passes. Alternating current, electricity device such as a radio or cellular telephone. In every case, that fl ows to and fro through a wire, repeatedly creates and these contacts are then recorded in a written document which increases these fi elds. 322 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. These developments gave strength to the theory of a Street Smart ground wave and to the idea that a signal could be transmit- ted across the ground. The fi rst “wireless” communication system used a ground wave for signal transmission. Efforts to In the United States, as a standard, alternating create a ground-based wireless system were met with frustra- current (AC) electricity passes through a wire tion, primarily because the use of alternating current was still 120 times in each second, or 60 cycles per second in its infancy, until Marconi intervened. (60 CPS), creating a temporary fi eld effect in the Guglielmo Marconi, of Bologna, Italy, utilized the works of Heinrich Hertz. In 1887, Hertz caused a spark to process. This electrical fi eld can be sensed by an ECG, leap across a gap and create an electromagnetic wave.9 At as 60 cycle interference, unless the cable and ECG that time, this phenomenon was known by various terms machine are shielded. including “ether waves” and “Hertzian waves.” Using this idea of an electric spark, Marconi invented a spark transmit- ter, a primitive black box with an antenna that could trans- mit the “spark,” or signal, over a distance to a receiver that would produce an audible snap. That snap, in turn, could At smaller frequencies, these fi elds tend to collapse, or be used similarly to the telegraph’s Morse code. This black dissipate, over time. However, scientists learned that when box, developed in December 1894, was eventually brought electricity approaches 10,000 CPS the electromagnetic fi eld to England. After obtaining a patent, the Wireless Telegraph tends to radiate outwards and the electromagnetic fi eld is and Signal Company was formed. Marconi, 23 years old at sustained. These radiating waves of electromagnetic energy, the time, would later receive the Nobel Prize for physics in or radio waves, can be detected at great distances In other 1908 for his invention. words, radio waves are a part of the spectrum of electromag- After the fi rst transatlantic wireless transmission in 1915, netic energy (Figure 18-2). wireless communications, a branch of telecommunications, The discovery of radio was a great breakthrough, espe- grew rapidly. The U.S. Navy, interested in the potential of cially for remote settings, such as at sea. Previously, sailors, wireless communications for ship-to-ship communication soldiers, and merchants depended on semaphore, a system of as well as ship-to-shore interactions, investigated Marconi fl ag signals that can be seen over great distances. Later, they and his device. Before long, many U.S. warships had a radio. depended on the hardwired telegraph before the advent of the Often the radio was placed in hastily constructed wooden wireless radio. sheds, later called the “radio shack,” on deck. Telegraph has a close relationship with the development Earlier radios, restricted by the technology of the of radio. Telegraph, a system of communication transmitted time, operated in either low-frequency (LF) or medium- over wires, was the predominant communication method dur- frequency (MF) ranges. They were subject to a great deal ing the 1800s. The fi rst telegraph message, sent by Samuel of atmospheric interference and were therefore reduced to F.B. Morse in 1844, carried the message, “What hath God using Morse code. Later developments in radio technol- wrought?”8 From that point, telegraph messages using Morse ogy, by such notables as Reginald Fessenden of Canada and code were the predominant means of rapid communication. Harold D. Arnold, permitted both voice transmission and Original telegraphs often used multiple wires, one for each transatlantic transmission. letter in some cases. There was a continuous effort to reduce the number of wires. Eventually, the telegraph required only two wires—one to signal and the other a return. Some scien- tists, thinking that electricity could travel through the ground Street Smart for thousands of kilometers, buried the return wire into the ground, and found that the telegraph still worked. The fi rst weather report, transmitted by the U.S. Department of Agriculture in 1912, may have Infra-red Ultra-violet represented one of the earliest uses of radio for public Visible safety.10 Public safety offi cials have continued to take light an interest in radio as a means of communication. Radio waves Gamma ray and x-rays 106 1012 10141015 1018 1022 Radio Technology Frequency (Hz) Radio technology has eclipsed even the wildest dreams of Figure 18-2 Radio waves in the electromagnetic those early radio pioneers. The fi rst mechanical radio wave spectrum. generators were restricted to a maximum of 100 KHz, Communications 323 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. To reduce static interference heard between radio trans- missions, called white noise, electrical engineers developed squelch control. Squelch control reduces the amount of sig- nal received between transmissions, narrowing the reception of radio waves, and eliminating background interference. There are two types of squelch control. Carrier |
squelch AM — Amplitude Modulation eliminates background static during pauses in a transmis- sion, essentially muting the radio between transmissions and thereby improving the message’s overall quality. Coded (or tone) squelch permits the radio to receive only the intended signal. Sometimes also called private line (PL), coded squelch eliminates reception of near-broadcast messages by only accepting signals with the correct code. The quality and the privacy of radio transmissions are thus improved. FM — Frequency Modulation Figure 18-3 AM radio transmission versus FM radio transmission. Street Smart In the past, public health nurses would take a severely restricting their usefulness. Later, electronic genera- portable AM transistor radio and dial it between tors, or oscillators, markedly expanded the properties of the radio wave. To achieve voice transmission, an audio signal radio stations and then place it over a pacemaker. produced from a microphone was “impressed upon” a radio The electric spark of the pacemaker could be heard signal, called a radio frequency (RF) carrier. This heralded distinctly on the radio. the era of radio telecommunications. To understand how an audio signal might be impressed upon a radio frequency, consider the analogy of fl otsam and waves. While the waves continue to crash on the beach, the Radio Frequency fl otsam, or audio signal, slowly washes to shore. Through Radio waves are transmitted literally at the speed of light. The modulation techniques which modify the wave by either difference in radio waves is not in the speed but rather in the changing the wave’s height (amplitude modulation [AM]) frequency of the waves in the radio transmission. These radio or by changing the wave’s speed (frequency modulation waves, measured in cycles per second, are called Hertz, after [FM]), the message can be carried through antennas to be the scientist who discovered them. A Hertz is an international transmitted (Figure 18-3). unit of measurement. One thousand Hertz, or cycles per second, Often the key to adequate radio transmission was the equals a kiloHertz, labeled kHz. Similarly, one million Hertz is size of the receiving or transmitting antenna. The length of called a megaHertz (mHz), and one billion is called a giga- an antenna is a function of the length of the wave. The lower Hertz (gHz). New electronic technology, using lasers, is able to the frequency, the longer the radio wave and, therefore, the generate a trillion Hertz, or a teraHertz (tHz) radio wave. longer the antenna. In some cases the radio wave was over The various radio waves are all part of the overall radio 20 feet, often making mobile radios impractical. To shorten spectrum (Figure 18-4). The human ear is able to detect radio antennas from being 9- or 10-foot-long “whips,” a radio sound in the form of waves in the 15 Hz to 20,000 Hz range. antenna would be cut down to one-half the wavelength, a The human voice is able to produce sound in the 200 Hz to half-wave antenna, or even one-quarter of the wave length. 2,500 Hz range.11 However, the radio spectrum goes from An antenna which was correctly matched to a radio greatly 3 Hz to over a trillion Hertz. The lowest radio frequency, improved radio transmission. termed extremely low (ELF), is between 3 and 30 Hz and However, despite an adequate antenna, the quality of is able to be transmitted over 5,000 miles or more. Perhaps many radio transmissions suffered from interference. Inter- more importantly, extremely low radio frequencies can pen- ference can be thought of as extraneous electromagnetic etrate water for a distance of several hundred feet. The ELF is energy heard on the radio as crackles and dead spots, some- therefore useful for submarine communications. times called static. Sources of static include other unshielded The next band of radio frequency, by international electrical devices emitting 60 cycle interference, lightning in designation, is the super-low (SLF) frequencies between the atmosphere, bursts of radio waves from sunspot activity, 30 to 300 Hz. The earliest radios were only capable of creating and even the spark plugs in an automobile. about 100 Hz, thus limiting them to the SLF frequency band. 324 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. 0.003 MHz 300 mHz, can be cleanly transmitted over 25 to 50 miles. Very low frequency (VLF) VHF is useful to EMS because it takes less power to transmit 0.03 MHz using the higher frequencies. This is an advantage for emer- Low frequency (LF) 0.3 MHz gency services telecommunications devices that depend on Medium frequency (MF) batteries. VHF is also the bandwidth used by commercial 3 MHz television broadcasts. High frequency (HF) 30 MHz Very high frequency (VHF) 300 MHz Ultra high frequency (UHF) Cultural / Regional differences 3,000 MHz Super high frequency (SHF) 30,000 MHz In rural and frontier environments, a transmission Extra high frequency (EHF) distance of 100 miles is too short. To overcome 300,000 MHz the problem of distance, some radio systems have Figure 18-4 The radio frequency spectrum. resorted to the use of radio repeaters. Repeaters— radios that pick up, amplify, and then retransmit a The next three radio bands—ultra-low frequency (ULF), radio transmission—can extend the range of a VHF very-low frequency (VLF), and low frequency (LF)—also almost indefi nitely. The transmission’s distance is a have limited utility because of extreme radio interference. function of the number of repeaters available. The medium frequency (MF), 300 to 3,000 kHz, was the fi rst to see extensive use because the problem of interference was being overcome. Early commercial radio stations, using AM technology that would transmit on RF carriers in the 550 to Ultra-high frequency (UHF) radios, in the 300 to 3,000 mHz 1,600 kHz range, started to broadcast entertainment programs range, can transmit in a LOS for 15 to 100 miles, dependent to the public using these new technologies. on terrain. If the UHF radio antenna is on-board an airplane, After the advent of crystal-oscillator radios, high- the distance can be boosted to over 300 nautical miles, and f requency (HF) radio transmissions, in the 3 to 300 mHz if the radio transmitter is in a satellite the signal can travel range, that were capable of “crystal-clear” transmission literally thousands of miles. Super-high frequencies (SHF), blossomed. These tighter radio waves were capable of being otherwise known as microwave transmissions, within the transmitted over the land, as a ground wave, from point A to 3 to 30 gHz bandwidth and extremely-high frequencies (EHF), point B. These waves provided remarkable quality as long as within the 30 to 300 gHz bandwidth, are used for satellite there were no obstacles in the line of sight (LOS) to block transmissions. While a SHF or EHF radio may be limited to the transmission. a LOS of about 40 miles, a SHF or EHF radio can literally To overcome the problem of obstacles to LOS, the HF bounce a signal off a satellite and back to Earth, bypassing radio antenna could be directed toward the sky. The HF radio obstructions such as mountains. This feature makes these sat- signal would rise until it struck the ionosphere, a layer of ellite phones, also called Earth stations, extremely useful in atmosphere where the sun’s ultraviolet rays ionize the gasses, frontier communities with little or no development, as well as and the signal would be refl ected back to Earth.12 This phe- in wilderness situations. nomenon, known as skip, could permit HF transmissions to At present, there are two satellite phone systems in place. travel over 300 miles on a sky wave. One uses satellites in a geosynchronous orbit. With as few Amateur civilian short-wave radio operators, using this as four satellites, these satellite phone systems can provide phenomenon to their advantage, can now communicate with worldwide coverage. Unfortunately, obstacles such as high other short-wave radio operators all the way around the world terrain can block the view of satellites on the horizon. To under the right atmospheric conditions by skipping signals resolve this problem, newer low Earth orbit (LEO) satellite from one receiver to another.13 These “ham operators,” as technology was developed. A LEO satellite is not geosyn- short-wave radio operators have come to be known, have chronous and orbits the Earth at a high rate of speed, with assisted during disasters and can be instrumental in other an average orbital time of 80 minutes. A LEO satellite phone public safety emergencies. system, such as Globalstar or Iridium, has a larger number of The principal radio frequency band used by emergency satellites in orbit, which are constantly crossing the sky and services is very-high frequency (VHF). VHF, from 30 to creating a grid with interlocking cells of coverage. Communications 325 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Street Smart Besides the obvious advantage of satellite phones in rural and frontier EMS, satellite phones are also useful during disasters. During a disaster, traditional telephone wires may be down and cellular towers “locked up” from overwhelming use. During these times, dedicated satellite phones could be used. Wave Propagation Figure 18-5 Mobile radio. As mentioned earlier, there are two types of wave propaga- tion: ground and sky. The distance that a ground wave travels A base station is a fi xed facility which generally serves is a function of its length. A longer wave will roughly follow as a focal point in an EMS system. Base stations generally a surface path. However, it is diminished by each obstacle it have more powerful transmitters because they do not rely meets (called fading) until either it is too weak to be received upon batteries. Hard-wired in the electric power supply, a or it reaches its target (the receiver’s antenna). A ground wave base station is vulnerable to power outages. For this reason, is also affected by the surface over which it travels. Soils that many EMS agencies have a backup power supply, such as a are poor conductors will shorten the length of the transmis- generator, to ensure reliable operation. sion whereas a HF radio transmission may travel 700 miles Mobile radios (Figure 18-5) are affi xed to vehicles and over the open water of the ocean. use the vehicle’s battery for power. Often the radio itself Shorter waves (e.g., UVF), when using a ground wave, is secured inside a trunk, or behind a seat, protected from are easily blocked by any obstacle in the LOS such as foliage impact in case of collision. A small remote radio control and buildings. Using a UVF radio in rough terrain, such as panel, called a radio head, is placed in the driver’s and/or a city, requires that the operator either build a tall antenna to patient compartment. overcome the obstacles, or depend on a phenomenon called The simplest radio system is simplex. A simplex radio bounce. Bounce occurs whenever a short wave strikes a only allows communication in one direction at a time. The refl ective surface and is redirected in another direction. With oldest example of a portable simplex radio may be the Motor- enough refl ective surfaces, the refl ected path will roughly ola walkie-talkie used in World War II. These handy portable result in the intended direction of travel. radios permitted communication between platoons and regi- Radios that use the sky wave, tropospheric (TROPO) mental command in the same manner that modern radios per- radios bounce the radio signal off the ionosphere in the direc- mit communication “car-to-car” between emergency vehicles tion of the receiver antenna. As radio signals are wave-like, a (Figure 18-6). sky wave will scatter, permitting worldwide reception.14 The The diffi culty with simplex radio |
is that it requires one United States military has used troposcatter radio systems party to complete the message before the other party can since the 1950s for long distance radio. respond. In some instances, it is desirable to have a dialogue. Radio Systems Thus, duplex radios were invented. A duplex radio operates in the same manner as a hard-wired telephone, referred to as Radio systems consist of components that permit a radio a landline. Using two frequencies—one to transmit and one message to be transmitted and received. The arrangement of to receive—an operator could talk and listen at the same time, radio components is referred to as the system architecture. permitting more rapid communications. Communication was Currently, two radio architectures exist in EMS: traditional enhanced since clarifi cation questions could be asked at the land mobile radio (LMR) architecture and cellular system time they were germane to the discussion. architecture. Multiplex radios permit the transmission of both audio signals as well as data. The transmission of an electrocardio- Land Mobile Radio Architecture gram (ECG), called telemetry, during patient report is an A traditional land mobile radio (LMR) architecture has many example of the use of a multiplex radio.15,16 components, in varying numbers, depending on the size, Transmission via a handheld radio is affected by the location, and complexity of the EMS system. Factors include size of the battery. A larger battery, while providing more the existence of base station(s), mobile radio(s), portable power, may be too bulky to be portable, thus limiting its use radio(s), and repeater(s). in the fi eld. 326 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Up to 1,000 watts Single 40' to 100' Antenna antenna Fixed frequency high power Shared several transceiver radio channels Microphone and Dispatcher speaker Up to Dispatch center 25 watts antenna Fixed frequency radio transceiver *Note: radios may have a manual switch to change frequencies Figure 18-7 Standard land mobile radio architecture. Figure 18-6 Portable radio. To improve the transmission distance of a portable radio, departments within a city at once, via a simulcast, or to all some EMS systems depend upon repeaters to boost the signal public services leaders, or to an individual department such (Figure 18-7). as EMS. Trunking also prevents one message from blocking another message. The computer, in the example used earlier, Computer-Assisted Radios would detect that an EMS message from a portable radio, a The overwhelming public demand for general radio frequen- high-priority communication, was more important than the cies within the available radio band set aside by the federal water department’s transmission. The computer could elect to government has forced some EMS agencies to have to share either switch the water department radio to another radio fre- radio frequencies with school buses, livery services, and pub- quency or to store the message in the computer’s short-term lic works departments. The resultant channel crowding may memory, so it could be rebroadcast when airtime became cause a high priority EMS radio transmission from a porta- available. This in effect gives emergency radio transmissions ble radio to be suppressed (walked on) by a more powerful a higher priority. mobile transmitter from another department. In examining the problem, engineers realized that the majority of time there Cellular System Architecture are no radio transmissions on any one channel and that this The advent of cellular telephones may have revolutionized so-called dead airtime could be used to greater effi ciency if emergency communications during day-to-day operations it was controlled. Using computers, engineers devised a tech- (Figure 18-8). Cellular telephones are actually low-powered nique whereby multiple users could communicate over fewer wireless transmitters (radios) that work within close prox- frequencies, with the computer selecting the frequency to be imity to a radio tower. Each tower provides service to an used based on availability. area referred to as a cell. Each mobile radio (cellular tele- This technique of computer-assisted radio commu- phone) has a forward link to the tower as well as a reverse nications, called trunking, has several other advantages. link and operates as a duplex radio within that cell. As the For example, a computer-assisted mobile or portable radio cellular phone reaches the boundaries of the cell, the next allows an administrator (e.g., a city manager) to talk to all tower (linked by computer) automatically transfers the call Communications 327 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Components of a Cellular System Radio telephony systems Forward link Mobile base station Reverse link Mobile Mobile base station control equipment PSTN Mobile Network operator interface equipment Figure 18-9 Facsimile (FAX) machines can receive high-quality electrocardiograms (ECG) Figure 18-8 Cellular radio system architecture. from the fi eld. to another radio channel, without interruption of service. As with distant medical centers where Paramedics may be able each tower switches, or hands-off, the transmission to the to benefi t from the available expertise. next tower, there is no interruption in transmission. The fi rst cellular systems, created in the late 1970s, were Alternative Communication Devices analog systems operating at 800 mHz and quickly became Both the facsimile machine (Figure 18-9) and the computer mainstream in the public. Unfortunately, transmissions have seen use as an alternative means of communication. The between cellular telephones could be picked up by multi- facsimile machine, using digital technology, can transmit a band receivers called scanners that monitor several radio fre- high-quality copy from one location to another (e.g., an elec- quencies, including those used by cellular telephones. This trocardiogram (ECG) can be sent to an emergency depart- practice of scanning for conversations breached patient con- ment or a cardiologist’s offi ce). fi dentiality and made cellular telephone use problematic for The advent of the computer has added a number of pos- Paramedics. sibilities. By using laptop or handheld computers inside a The subsequent generations of cellular service, such vehicle, called a mobile data terminal, a Paramedic can cre- as the personal cellular service (PCS), used digital service ate a document and then download it for transmission over instead of analog. Digital cellular systems have encrypted a telephone line, via modem, over the Internet, or by using voice and data features that increase security and help main- wireless technologies including Bluetooth®. Paramedics can tain the confi dentiality of patient information.17,18 also use palm-sized personal digital assistants (PDA) or Cellular Telephone personal palm computers (Figure 18-10) and move about the patient compartment at will, all the while transmitting and There are three varieties of cellular phones or mobile sub- receiving critical patient information. scriber units (MSU) for use within a cellular radio system. The most common MSU is the portable cellular telephone which boasts about 0.6 watts of power. These small, personal Public Safety Communications cellular telephones are convenient but often lack the range The fi rst use of a telephone to call for emergency medical necessary to reach towers outside of a service area. assistance may have occurred when Alexander Graham Bell The transportable cellular telephone boasts more power, spilled acid on himself and called out over the telephone, 1.6 watts. However, its larger battery makes it less convenient “Mr. Watson, come here, I want your help.” From those early to carry. The mobile telephone, with its 4.0 watts of power, beginnings, telecommunications, and especially radio, have is powerful and dependable. The mobile telephone is usually grown enormously. mounted to the interior of the vehicle and has an external The easy availability of either radio transmitters or radio antenna to improve reception. components created a surge of amateur radio enthusiasts, New satellite mobile telephones, formerly the sole many of whom competed with commercial radio providers domain of the military, are seeing increased use, especially in for the limited radio bands. To stem this growing problem, remote and rural areas where cellular service is often unde- Congress passed a resolution, the Communications Act of pendable or nonexistent. Satellite telephones offer the prom- 1934, which states that the President of the United States ise of dependable and secure (encrypted digital) connectivity has control over all government radios and that the Federal 328 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Figure 18-10 Paramedic using a PDA on-scene. (Courtesy of Computerworld Honors Program) Communications Commission (FCC) has control over the civilian use of radios.19,20 The FCC, the agency with rule-making and enforcement responsibility, quickly began allocating frequencies to spe- cifi c interest groups and then required them to license with the FCC for permission to use those frequencies. The earliest frequencies assigned to public safety included those in the VHF and UHF bandwidth.21 Early EMS Radio Communications Despite the availability of a number of designated radio fre- Figure 18-11 Dedicated emergency hotline. quencies for public use, a 1970 study showed that less than 5% of ambulances had a mobile radio. In the seminal white the importance of communications to the “chain of survival,” paper, “Accidental Death and Disability,” one recommenda- EMS communications continue to be problematic. tion spoke of the need for dedicated frequencies for EMS: frequencies to be used between the ambulance and the hospi- Phases of EMS Communications tal as well as between the dispatch center and the ambulance. There are three phases of communication in every EMS Another recommendation advocated for a centralized radio incident: (1) the occurrence and the detection of the occur- and telephone communications center. During that era, it was rence, (2) the notifi cation and response of responders, and not uncommon for a citizen to either call the operator for help (3) the treatment and transportation of the patient. Delays due or call a seven-digit emergency hotline. These hotlines, dedi- to communications problems during any one of these three cated telephone numbers, usually rang into someone’s house. phases can result in increased harm, and even death, for the That person would then use a call-down tree to summon an patient. emergency crew. Some hospitals still maintain an emergency hotline (Figure 18-11) as a backup to radio communications. Detection While other emergency notifi cation systems also evolved, In 1967, the President’s Commission on Law Enforcement they all had one thing in common: ineffi ciency. and Administration of Justice recommended that there be a The fi nal recommendation of the white paper called for single universal emergency number in the United States. Brit- the creation of a single nationwide telephone number for all ain had used a national three-digit emergency number, 9-9-9, emergency services. The practice at the time was that every since 1937 and had a great deal of success with a universal jurisdiction had its own seven-digit emergency telephone number. In November of 1967, the FCC and the American number. Unfortunately, the telephone company’s service area Telegraph and Telephone Company (AT&T) announced that did not always line-up with the boundaries of a particular AT&T would use 9-1-1 as its universal emergency number in EMS service. This resulted in frequent errors. all of the areas served by AT&T. The number 9-1-1 was cho- Despite the recognition of communications as an inte- sen, in part, because no exchange or area code in the AT&T gral component of EMS and a growing public awareness of system used the number 9-1-1. Communications 329 Copyright 2010 Cengage Learning. All |
Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. infant. After reviewing the incident, Chief Allen Brunacini of the Phoenix Fire Department ordered that callers receive instruction on how to self-rescue before responders arrived. Most current EMS dispatch procedures include some form of prearrival instruction. This instruction, called medical self- help, added another dimension to the role of communications specialists—being the “fi rst” fi rst responder. Notifi cation and Response The next phase of emergency communications is the notifi ca- tion phase. During the notifi cation and response phase, the greatest danger is posed for a Paramedic. Using the lights and siren in response to an emergency, the Paramedic is at risk of bodily harm secondary to motor vehicle collision. This Figure 18-12 Communciations center or public danger is accepted in light of the potential good which can be safety access point. created by prompt treatment of the patient as well as the fact that the danger can be mitigated by the cautious operation of the emergency response vehicle. Nevertheless, in many Shortly thereafter, on February 16, 1968, Representative cases, Paramedics and the public are put in harm’s way dur- Rankin Fite, Speaker of the House of Representatives, placed ing a call for assistance in which a delayed response would the fi rst 9-1-1 call in Haleyville, Alabama. Since that fateful not harm the patient. Concerned about the widespread prac- fi rst call, 9-1-1 service has been extended to over 96% of the tice of sending all EMS units out with lights and sirens on to United States. Canada has also adopted the 9-1-1 emergency the scene regardless of the nature of the emergency, in 1977 number, making it an international emergency number. Dr. Jeff Clawson went about systematically placing EMS When a 9-1-1 call is placed, a specially trained “call- calls in a priority classifi cation. taker” takes down information regarding the nature of the Dr. Clawson’s objective was to send the right response to emergency to pass along to fellow workers or responders. the right person at the right time. Original trials of the new The entire 9-1-1 operation is generally located in a central- Medical Priority Dispatching™ were successful in Salt ized communications center called a public safety access Lake City, Utah, and the system proliferated across the United point (PSAP) which runs 24 hours a day, seven days a week States and Canada.22,23 According to emergency medical dis- (Figure 18-12). patch (EMD) protocols, the communication specialist was Subsequent generations of 9-1-1 service have been to interrogate the caller, give prearrival instructions, and use enhanced (E9-1-1) to include a call-back feature as well as preset criteria to make a response determination before dis- location identifi er. These features allow emergency commu- patching the appropriate EMS responder units. nications specialists (COMSPEC) to dispatch emergency The use of EMD has become so widespread in the United responders to people who are unable to speak or who have States that the American Society of Testing and Materi- lapsed into unconsciousness. als (ASTM) issued a practice standard in 1990. In addition, At its inception, 9-1-1 service was very effective in get- the National Association of Emergency Medical Services ting help to those in need of assistance. However, the wide- P hysicians (NAEMSP) advanced a position paper that essen- spread use of mobile cellular telephones has reduced some of tially states that EMD is the standard of care for dispatching the advantages of the E9-1-1 system. Communications spe- EMS calls. cialists receiving a 9-1-1 call from a cellular telephone do not have a call-back number nor do they have a location identifi er First-Due Report to assist them with rushing aid to the patient’s side. Recogniz- Almost all Paramedics notify the PSAP of their depar- ing this problem, the telecommunications industry has agreed ture from their assigned post or station and their arrival to rectify the problem in two phases. During phase I, cellular on-scene. In some cases, particularly where there are mul- telephones will not only provide a call-back number to the tiple casualties, a fi rst-due report is important for scene PSAP but also provide the location of the transmitting tower. command and control. A fi rst-due report is a brief synop- During phase II, the cellular telephone will be able to emit sis of the scene size-up obtained by the fi rst arriving EMS a location fi nder, a homing beacon of sorts, which multiple responder. Typically it includes the exact location of the towers can use to triangulate the position and give the cellular call, the nature of the incident, known or suspected hazards, telephone’s exact location in terms of latitude and longitude. and the anticipated number of patients. If special resources (e.g., heavy rescue) are needed, they would be requested at Prearrival Instructions that time. In 1975, Phoenix fi refi ghter Paramedic Bill Tune success- In the 1920s, police offi cers used 10-codes. These fully coached a woman while she performed CPR on her police departments often had one radio frequency and used 330 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. 10-codes as abbreviated messages designed to minimize complete past medical history may appear helpful, this airtime. In 1940, the Associated Police Communications Offi - amount of information may serve to only confuse the phy- cers, now the Association of Public Safety Communications sician who is trying to understand the underlying problem. Offi cials (APCO), published its fi rst 10-code list. Since that A Paramedic uses judgment to select the information that is publication, and despite efforts at standardization, dozens of pertinent to share with the physician in order to optimize time versions of the 10-code have been created. These 10-codes and increase effi ciency. are useful when only used intradepartmentally; however, the The Paramedic would then proceed to the physical exami- use of 10-codes can be confusing in cross-jurisdictional com- nation. Paramedics will have already completed an initial munications, and especially to responding mutual aid com- survey. If the patient is high priority, then all life-saving inter- panies that do not use the same codes. Therefore, many EMS ventions should be conveyed to the physician in a standard ABC systems and disaster planners prefer the use of plain English order. Provided that all life-threatening conditions have been transmissions and discourage the use of 10–codes. treated and temporarily stabilized, the Paramedic would then proceed to report the patient’s vital signs: temperature, pulse, Radio Conduct respirations, and blood pressure. Following the initial assess- While plain English transmissions can be clear, the ability to ment and vital signs, the Paramedic should report the fi ndings use plain English has caused some emergency personnel to of a focused/vectored physical examination (PE). The Para- take free license and use vulgarity over the air. The FCC has medic understands that he is the emergency physician’s eyes the authority to fi ne, suspend, or terminate any radio license and ears in the fi eld. The Paramedic should anticipate what for failure to comply with the standards for radio opera- observations the physician will likely request. Clinical prac- tion, including the misuse of radio or use of profanity while tice, working side-by-side with the emergency physician, can on-the-air. As a result, and as part of the culture of EMS, a help educate the Paramedic as to the expectations that a physi- characteristic form of spoken communication has arisen. Fre- cian will have for a physical examination report. quently, Paramedics will use a standard nomenclature, such In the case of a medical patient, the history of present as the terms “affi rmative,” “negative,” and “stand-by,” as well illness plays a pivotal role in the decision-making process. as the use of concise radio reporting style, to ensure that a In the case of a trauma patient, the mechanism of injury clear message gets through. It is also common for Paramed- coupled with the physical examination fi ndings is of para- ics to suspend pleasantries, such as saying “please” or “thank mount importance. Paramedics learn through experience to you” during a transmission. There is an implicit understand- emphasize the appropriate fi ndings according to the patient’s ing among Paramedics that the Paramedic is both courteous presentation. Once the patient presentation is complete, it is and professional when foregoing the use of pleasantries in appropriate for the Paramedic to make a fi eld diagnosis of favor of conserving airtime. the patient’s condition. Providing a fi eld diagnosis over the radio helps the emergency physician understand the Para- Treatment and Transportation medic’s direction and intent. At this time, the EMS physician Communications can ask for more assessment fi ndings, both history and physi- The Paramedic shares a special relationship with an emer- cal, as well as redirect the Paramedic’s attention to alternative gency physician that requires a more complete disclosure of conclusions. the patient’s condition than would be expected from an EMT. What follows is usually a discussion of the treatments This duty is owed, in part, because of the invasive procedures provided up to that point in time, including their effect, and that a Paramedic is allowed to perform. Typically, when a Para- a dialogue about how to proceed. Whenever a Paramedic medic is contacting medical control for guidance and instruc- accepts a medical order, he or she should practice the echo tion, the report begins with the Paramedic’s identifi er. Many technique. With echo technique, when the physician gives an systems assign numbers to Paramedics which indicate that order the Paramedic should repeat the order back to the phy- the person on the radio is a recognized Paramedic with clini- sician exactly as received. The physician should then confi rm cal privileges. The following format is an example of a stan- the accuracy of the read-back. dardized radio report. Each EMS system varies with regard to To prevent confusion, some EMS systems only allow the information required and the order of presentation. a Paramedic to accept one order at a time. Stacking orders, Starting with patient demographics (age, sex, and weight each received one at a time, is acceptable provided that ade- in kilograms) and the patient’s chief concern (in the patient’s quate time is permitted between interventions to assure that own words, if possible), the Paramedic would provide a his- the therapeutic goal has been met, or not met as the case may tory of the present illness (HPI). Mnemonics such as AEIOU be, before proceeding. TIPS or PQRST can be helpful in organizing the mass of Many systems also require an alert report be sent to patient health information into a meaningful whole. the triage station or a charge nurse. In some EMS systems, the What follows is the patient’s past medical history Paramedic is tasked with alerting the receiving facility. The (PMH). The mnemonic AMPLE can be useful for orga- information in the alert report is brief and concise: age, sex, nizing the patient’s information. While advising the physi- chief complaint, mental status, vital signs, treatments in prog- cian about every allergy, every medication, and the patient’s ress, and an estimated time of arrival (ETA). Communications 331 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Radio Diffi culties The question of interagency interoperability is impor- tant in the post September |
11, 2001 era. It is imperative that Paramedics frequently encounter problems while trying to all public safety agencies be able to communicate with one operate their radio systems. The Public Safety Wireless Net- another in order to more effi ciently carry out their mission work study indicated that some 15% of public safety provid- with the maximum degree of safety. The Fire and EMS Com- ers had problems with static, batteries, or both, while another munications Interoperability study indicated that less than 23% complained of signal fading. Despite the fact that 24 35% of the agencies surveyed—some 1,045 agencies nation- more mHz of bandwidth has been dedicated for public safety wide—indicated confi dence in the interoperability of their use, some 32% of public safety providers complained about radios during a large scale task force operation typically seen channel crowding. at a multiple casualty incident. 332 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Whether communicating with other members of the healthcare team or the public safety team, the quality of communications is important to overall teamwork. Working as a team, and optimizing communications at both levels, will help facilitate patient care and the patient’s recovery from a medical emergency. Key Points: • Paramedics are a part of both the public safety • The principal radio frequency band used by team and the healthcare team. Communication emergency services is very-high frequency within the public safety team, made up of law (VHF). VHF, from 30 to 300 mHz, can be cleanly enforcement offi cers, fi refi ghters, and Paramedics, transmitted over 25 to 50 miles. serves to provide safety to the rescuer, the public, and the patient. • To overcome the problem of distance, repeaters— which pick-up, amplify, and then retransmit a • The Paramedic’s communication with the radio transmission—can extend the range of a VHF healthcare team serves the patient’s interests almost indefi nitely. by providing the patient’s past medical history, information about the history of the patient’s • Two radio architectures exist in EMS today: present illness, and the patient’s response to traditional land mobile radio (LMR) architecture prehospital treatment. and cellular system architecture. • Communication occurs between team members as • The simplest radio system, simplex (or a walkie- well as with other teams. talkie), only allows communication in one direction • at a time. Interfaces can occur in both oral and written forms. • • A duplex radio is similar to a landline and uses two AM and FM radio signals are generated through frequencies. One frequency is used to transmit and modulation techniques which modify a wave by one is used to receive, allowing an operator to talk either changing the wave’s height (amplitude and listen at the same time. modulation [AM]) or by changing the wave’s speed (frequency modulation [FM]). The message can then • Multiplex radios permit the transmission of both be carried through antennas to be transmitted. audio signal as well as data such as telemetry. • The antenna’s length is a function of the wave’s • To reduce channel crowding, computers allow length; therefore, an antenna correctly matched multiple users to communicate over fewer to a radio greatly improves radio transmission. The frequencies by selecting the frequency to be used difference in radio waves is not in the speed but based on availability, a process called trunking. rather in the frequency of the waves in the radio transmission, measured in cycles per second or Hertz. • Cellular telephones are actually low-powered wireless transmitters (radios) that work within • To overcome obstacles in the line of sight that can close proximity of a radio tower. block transmissions, high-frequency radio waves are directed toward the atmosphere and the signal • Technology today allows Paramedics to use is refl ected back to Earth, covering great distances laptop or handheld computers along with with great quality. personal digital assistants (PDA) before, during, Communications 333 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. and after calls to gather, transmit, and receive • The fi rst phase of communication in an EMS incident critical patient information using cable or wireless is a call received at a centralized communications technologies. center or public safety access point. • The Communications Act of 1934 granted the • The next phase of emergency communications is the Federal Communications Commission (FCC) control notifi cation and response phase. over all civilian use of radios. • The third phase of emergency communications is • The 9-1-1 system that we use today, which covers the treatment and transport of the patient. over 96% of the United States, was adapted from the British 9-9-9 national emergency number and • Paramedics need a formalized radio report initially put in place by AT&T. method. Review Questions: 1. What is meant by the duality of EMS 6. Compare the two radio architectures that exist communications? in EMS. 2. Where did radio communications get its start? 7. Who has control over the civilian use of 3. What is the principal radio frequency band used radios? by emergency services? 8. Describe early EMS radio communications 4. What is the difference between amplitude and the development of public safety access modulation and frequency modulation? points. 5. Describe ways the transmission and reception of 9. List and describe the elements of a radio report. a radio signal can be improved. Case Study Questions: Please refer to the Case Study at the beginning of the 3. H ow does communication improve a Paramedic’s chapter and answer the questions below. clinical decision making? 1. W hat should be included in the radio report to 4. I f you were asked to manage and provide EMS the medical control physician? for a large event in your area, how would you 2. H ow important was the fi rst-due report given by the assess the importance of communication between fi rst member of the public safety team on-scene? the public safety team and healthcare team? References: 1. Kelly CG. The ways and whys of documentation. Good 4. Lazar RA, Schappert RJ, 3rd. Presumed insuffi cient. The impor- documentation is more than what’s on a PCS form. Emerg Med tance of the prehospital care report. Jems. 1991;16(1):101–104. Serv. 2007;36(7):30. 5. Harkins S. Documentation: why is it so important? Emerg Med 2. Perkins TJ. Tell me a story. The importance of good Serv. 2002;31(10):89–90, 93–94. documentation. Emerg Med Serv. 2007;36(9):30, 32–33. 3. Krentz MJ, Wainscott MP. Medical accountability. Emerg Med 6. Maltz HM. EMS documentation. A legal necessity to avoid Clin North Am. 1990;8(1):17–32. liability claims. Emerg Med Serv. 2002;31(10):96, 98, 146. 334 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. 7. Erich J. Documenting your life away: common EMS report hand-held device for patients with acute myocardial errors. Emerg Med Serv. 2003;32(11):47–49, 52. infarction (from the Timely Intervention in Myocardial 8. Mabee C. The American Leonardo: A Life of Samuel F. B. Morse. Emergency, NorthEast Experience [TIME-NE]). Am J Fleischmanns: Purple Mountain Press; 2000. Cardiol. 2006;98(9):1160–1164. 9. Hertz H. Electric Waves: Being Researches on the Propagation 17. Nazeran H, Setty S, et al. A PDA-based fl exible of Electric Action with Finite Velocity Through Space. New York: telecommunication system for telemedicine applications. Cornell University Library; 1893. Conf Proc IEEE Eng Med Biol Soc. 2004;3:2200–2203. 10. http://www.nal.usda.gov/speccoll/collectionsguide/mssindex1. 18. Kline JA, Johnson CL, et al. Prospective study of clinician- shtml entered research data in the emergency department using an 11. Fausti SA, Erickson DA, et al. The effects of impulsive noise Internet-based system after the HIPAA Privacy Rule. BMC upon human hearing sensitivity (8 to 20 kHz). Scand Audiol. Med Inform Decis Mak. 2004;4,(17):1–16. 1981;10(1):21–29. 19. Granados MR, Sr. New FCC rules affect EMS radio 12. Sizun H. Radio Wave Propagation for Telecommunication frequencies. Emerg Med Serv. 1996;25(2):24–25. Applications (Signals and Communication Technology). New 20. Johnson MS, Van Cott CC. The FCC may be listening. An York: Springer; 2004. update on EMS communications. Jems. 1992;17(5):19–24, 13. http://www.arrl.org 26–27. 14. Tse D, Viswanath P. Fundamentals of WirelessCcommunication. 21. Johnson MS, Van Cott CC. New radio service targets EMS New York: Cambridge University Press; 2005. communications. Emerg Med Serv. 1993;22(7):70–74. 15. Sillesen M, Sejersten M, et al. Referral of patients with 22. Kuisma M, Holmstrom P, et al. Prehospital mortality in an EMS ST-segment elevation acute myocardial infarction directly to system using medical priority dispatching: a community based the catheterization suite based on prehospital teletransmission cohort study. Resuscitation. 2004;61(3):297–302. of 12-lead electrocardiogram. J Electrocardiol. 2008; 23. Bailey ED, O’Connor RE, et al. The use of emergency medical 41(1):49–53. dispatch protocols to reduce the number of inappropriate scene 16. Adams GL, Campbell PT, et al. Effectiveness of prehospital responses made by advanced life support personnel. Prehosp wireless transmission of electrocardiograms to a cardiologist via Emerg Care. 2000;4(2):186–189. Communications 335 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. KEY CONCEPTS: Upon completion of this chapter, it is expected that the reader will understand these following concepts: • The patient care report as an important medical, business, and legal document • The patient care report as part of the quality assurance and performance—improvement program • Different formats available for documentation that focus on a precise refl ection of the events that occurred • Special incidents, such as disasters, that require special reports Case Study: After all the excitement of the cardiac arrest was over, the new Paramedic realized she was faced with the tedium of documentation. Her senior Paramedic partner reminded her that documentation is important. He said, “The patient care report is a medical document that helps the physician determine the cause of the cardiac arrest. The patient care report is also used as a quality improvement tool, allowing our supervisor to ascertain whether we met certain performance goals, to identify weaknesses in our performance and to help establish training goals to correct those weaknesses. And,” as he continued, “the patient care report is a legal record.” Nodding acknowledgment she opened up the laptop and started to fi ll the fi elds. 336 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Documentation 337 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if |
subsequent rights restrictions require it. OVERVIEW Documentation—whether it consists of patient care reports, special incident reports, affi davits, or triage tags—is an important responsibility for Paramedics. One study suggested that Paramedics spend as much as 28% of their patient contact time writing the patient care report (PCR), underscoring its importance.1 Some Paramedics, in order to focus on patient care, facilitate their report-writing by taking notes on 3 5 cards or notepads and then transcribe their notes to a more formal PCR later. It is also common to see a Paramedic writing critical patient information on a piece of tape affi xed to a pant leg or on the corner of a sheet. Purpose of EMS Documentation Patient care documentation is a record of the pertinent fi nd- ings and observations of the patient’s health obtained through examination. It is also a log of the tests and treatments performed. There are six-fold reasons for Paramedics to write an accurate patient care report. First and foremost, the PCR is a part of the patient’s present medical care. Based upon the outcomes of treatments, noted on the PCR, the emergency department can make further treatment decisions. The PCR is a communication tool between the Paramedic, who has left the patient, and the emergency physician at the hospital still treating the patient. The PCR is therefore essential to the con- tinuity of patient care. It emphasizes the Paramedic’s role as Figure 19-1 Physicians use prehospital patient a part of the healthcare team as well. care records to obtain information that might Second, the PCR is also a part of the medical record, otherwise be unavailable. which will be used in the future by other physicians and allied healthcare professionals for patient care. As a part of the medical record, the PCR often provides vital informa- Fourth, the PCR is a business record used for billing tion to physicians about the origin of a condition or disease and operations. Careful and accurate documentation helps (Figure 19-1). to ensure that insurance claims reviewers, during utilization For example, a PCR written about a low-priority patient review, will accept the patient care charges submitted. contact during a hazardous materials spill may be the evi- Fifth, EMS researchers may also use the PCR as a research dence that links a minor exposure to a toxin to liver cancer document. Following changes in EMS care documented on 20 years later. the PCR, researchers can publish either descriptive research Third, the PCR is a tool for quality assurance and per- fi ndings or, using an experimental design, investigate new formance improvement programs. Through PCR audits—a treatments in the fi eld. careful review of the documentation for specifi c data— EMS educators often use selected PCRs for case pre- healthcare managers, EMS administrators, and EMS physi- sentation in a case of the utility of a practice. EMS physi- cians can assure that the patient care provided out-of-hospital cians, in the course of a medical audit, often select illustrative meets the established standard of care. PCR audits help to cases documented on a PCR for individual instruction or an ensure that acceptable patient care is provided to all patients agency’s continuing education. The PCR can also be utilized equally. in a case-based method of teaching. These PCRs are often Analysis of the results of these PCR audits also helps to illustrative of a unique solution to an unusual problem or as a identify trends, such as increased patient contacts in a certain reinforcement to established methods. segment of a city or a consistent problem with patient care in Finally, the PCR is a legal record. The Paramedic can a specifi c patient population. Identifi cation of system issues be subpoenaed to court with the PCR to testify during a trial in this manner provides EMS managers with an opportunity (Figure 19-2). The PCR can be used as evidence in a trial. to remodel the system or educate the Paramedics. The trial may or may not even involve EMS as an issue. That 338 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. The last statement is somewhat problematic as it assumes a foreknowledge of a determination yet to be made. Appreci- ating that the patient lacks this knowledge, and that the patient calls for EMS because of a belief that it is an emergency, the federal government has accepted the prudent layperson stan- dard. The prudent layperson standard means that another person, not a physician, who was in the same or similar cir- cumstances would think it is appropriate to call EMS; this is paraphrased from larger state and federal defi nitions.4,5 However, simply stating that there is a medical emer- gency, using the previous standard, is insuffi cient information for the purposes of the medical record, utilization review, and the courts. To fulfi ll the needs of these other parties, the Para- medic needs to provide complete documentation of care from Figure 19-2 The prehospital patient care report the arrival on-scene to the transfer of care at the hospital. is a legal document as well as a medical record. Following a proscribed format the Paramedic should legibly write down his or her observations on the patient care record in black ink. If an action or observation is not PCR, exhibited to others in the legal system and the public, documented, then that information is lost. While the loss of refl ects upon its author and all other Paramedics.2 vital information can potentially harm the patient, it also A PCR is an important tool for a Paramedic during a calls into question the thoroughness of the Paramedic’s trial. With the number of lawsuits against Paramedics rising, exam and the justifi cations for treatment. The saying “If it Paramedics will depend on the PCR as a source of informa- wasn’t written down, then it didn’t happen,” suggests that a tion to aid recall for activities on an EMS scene which may treatment performed by the Paramedic is considered never have occurred fi ve or six years previously.3 to have happened, despite a Paramedic’s protestations, if it wasn’t recorded. As a result, there may be an appearance Elements of a PCR of dereliction of duty or possible negligence on the Para- medic’s part. A PCR has many fi elds, which are places to enter data. Most of the fi elds are for patient care information, although some fi elds on a PCR are for administrative and/or business information. Street Smart In the past, documentation of patient care was impre- cise and simply noted. For example, documentation may The use of black ink for documentation permits a have stated that a person was transported and indicate very little else. clear copy when the PCR is faxed, photocopied, Physicians have entrusted a great deal of responsibility microfi ched, or scanned into a document reader. to Paramedics. However, physicians need to know how the For this reason, many agencies only permit black ink patient was treated in the fi eld. This reveals the need for thor- to be used. ough documentation. In addition, administrators (both public and private) who have interested “stakeholders,” as well as the legal system, have mandated more thorough documenta- Legibility is another important issue in documentation. tion of patient care. The purpose of the PCR is to transfer the information to, or Documentation Standards communicate with, the physician and other patient care pro- viders. If the writing is indecipherable, then the function of At a minimum, a Paramedic should document the reason for the document is lost. It is a good practice to have another Para- the urgent transportation of a patient to an emergency depart- medic, one who was on-scene, read the PCR. Such proofread- ment. The federal Center for Medicare and Medicaid Ser- ing serves several purposes. It helps to establish consensus vices (CMMS), in its defi nition of an emergency, states that regarding the observations and actions of the team, as well as an EMS call is medically necessary when the patient experi- ensures the readability of the PCR. ences a sudden onset of acute symptoms for which emergency The use of slang and jargon in a PCR is inappropriate and medical intervention at a hospital would seem necessary. unprofessional. Such terms do not add to the patient record Medical necessity further requires that the absence of imme- and unnecessarily serve to distract the reader from the mes- diate medical attention could reasonably result in jeopardy sage. Similarly, bias and prejudice have no place on a PCR. to health, serious impairment of bodily function, or a serious As a rule, Paramedics practice conservation with words dysfunction of a body organ or part. and avoid excessive wordiness. While reading such technical Documentation 339 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. writing may seem dry, its intention is to be precise and to The central question with facsimiles is confi dential- convey a maximum amount of information in a short period ity (i.e., did the PCR get to the intended recipient?). When of time. “faxing” a PCR, the Paramedic should contact the receiver and advise that a facsimile will be transmitted shortly. When Errors and Omissions the facsimile is received, the recipient should respond with a When an error is made on the PCR, the Paramedic should verifi cation of receipt. “strike-out” the mistake with a single line, leaving the content If the PCR is inappropriately sent to the wrong address, below the strike-out legible. Next to the strike-out, the Para- the cover sheet should clearly indicate that the facsimile is medic should place the date and initial the strike-out to indicate confi dential and ask the recipient to destroy the copy. If the authorship. Heavy cross-outs give an appearance of deception, Paramedic knows that the transmission was made in error, as does the use of erasure polishes such as White-out®, leaving then the Paramedic should call the other party and request the Paramedic open to questions about integrity. that the unintended recipient destroy the PCR. It is common practice to place a single diagonal line Current regulations under the 1996 Health Insurance across any open areas of the document, called “line-out,” in Portability and Accountability Act (HIPAA) may make the use order to prevent the addition of new content to a PCR by oth- of a facsimile machine inadvisable in the future (Figure 19-3). ers after the Paramedic has completed the PCR. Also, such practices should be carefully scrutinized for compli- Upon completion of the document, some Paramedics ance with regulations regarding confi dentiality.6 sign-out with time, date, and initial after the last entry. The line-out and the sign-out indicate that the PCR was written Forms of Documentation and completed by the person listed “in-charge” at the time and date listed. Electronic Documentation Upon re-reading the PCR and determining an entire pas- Electronic documentation, although still in its infancy, is rap- sage or entry is substantially in error, the passage should not idly becoming state of the art. The use of mobile data ter- be removed but instead “crossed out” with a single slash that minals (MDT) on-board the ambulance or personal digital is then dated and initialed. A revision should then be writ- assistants (PDA) have replaced the pad and paper. ten on another page or on a continuation form with cross- Electronic documents have several advantages over tradi- reference made to the fi rst entry (e.g., see PCR 123). tional documentation. Computers have built-in spell checker It is also permissible to add to the record after the call. and grammar checker |
programs, increasing the readability of In that instance, another page should be added. Additions the PCR. Electronic documents can also have forced fi elds, should only be added when the entry will substantially clarify mandatory fi elds which must be completed before submis- the record or document important patient information useful sion. The use of forced fi elds helps to ensure that a minimum to the physician. data set is completed. Data sets are discussed shortly. As a rule, there should be only one author for each PCR. Concerns about limited data entry has plagued electronic Multiple authors generate concerns about the authenticity of documentation programs in the past, but the addition of drop- the document and the accuracy of the events depicted. Dis- down menus and handwriting recognition programs have cussion and collaboration with fellow EMS providers during helped eliminate some of those concerns. the creation of the PCR should eliminate the need for mul- To ensure patient confi dentiality, all electronic docu- tiple authors (Table 19-1). mentation programs should be password protected and the Confi dentiality Some Paramedics use a facsimile machine to transmit docu- mentation (e.g., to send the PCR from a base station to the Completed P hospital). The use of a facsimile machine (FAX) may be CRs acceptable provided a few safeguards are in place. Table 19-1 Documentation Standards • Black ink is preferred. • Legibility is important. • Slang and jargon is not used. • Errors noted with single strike-through and initialed. • Empty space is lined out. • Sign-out includes initials, date, and time. • One author for each record. Figure 19-3 HIPAA regulations impact recordkeeping. 340 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. password changed as frequently as every 30 days. To further EMS PCR Formats safeguard patient confi dentiality, Paramedics should rou- tinely shut down documentation programs when not in use Early EMS providers adopted the SOAP notes system for to prevent uninvited intruders from entering the program and their documentation system. In some states, the progress note altering the record. was virtually a blank sheet of paper, called an open form. The Paramedic was expected to document assessments and On-Scene Medical Records other information in SOAP format on the paper. While this approach permitted a great deal of freedom for document- The combination of mobile data terminals, secure satellite ing the patient’s condition in a narrative manner, almost like uplinks, and computer databases makes the possibility of telling a story, it made data gathering diffi cult for both the obtaining patient medical records, while on-scene, not only physician (who had to read the entire report to fi nd one vital possible but probable. The American Society of Testing and piece of information) and researchers (who looked at dozens Materials (ASTM) has already produced standard F1652-95, of reports for one set of information). Standard Guide for Providing Essential Data Needed in In response to the need for standardized data collection, Advance for Prehospital Emergency Medical Service. The minimum data sets have been established. A minimum data standard includes requirements for secure access and autho- set requires that the Paramedic complete certain fi elds with rized use in order to protect patient confi dentiality, as required the requested information. The minimum data set permits the under federal HIPAA regulations. Paramedic and physician to track trends and note patient prog- ress. A simple example of a data set would be response times. Problem-Oriented All EMS agencies strive to meet preset maximum response Medical Recordkeeping times (e.g., to be on-scene, or off the fl oor, in 10 minutes). In the past, physicians had private records for each patient that Some agencies are obligated by contract to be on-scene in a were stored in their offi ces. These were shared only with the minimum time. In both cases, the EMS agency wants to know patient and offi ce staff whom the physician generally knew its response times. personally. Tracking the progression of a patient’s disease in Every data set must also have a defi nition. In the previous some cases was largely a function of the physician’s memory. example, does scene arrival mean when the ambulance is at With the advent of hospitals, medical specialties, and the dispatched location or at the patient’s side? The differ- allied healthcare providers, all of whom need the same infor- ence in these two interpretations of response times can mean mation, some order had to be brought to the massive collec- minutes to a patient—minutes that make a difference in the tion of records generated for each patient by each provider. To patient’s survival, such as with cardiac arrest. help solve the dilemma, Dr. Lawrence Weed of the Univer- The American Society of Testing and Materials (ASTM) sity of Vermont’s Medical School advocated the concept of has proposed a minimum data set for EMS, standard E1744. problem-oriented medical recordkeeping (POMR) infor- E1744-04 contains similar data sets as the Data Elements mation systems in 1969 to track and manage patient records. for Emergency Departments (DEEDS), a program distrib- In a POMR system, the master problem list of the uted by the Centers for Disease Control and Prevention in record would list the medical conditions for which that 1979. Inclusion of DEEDS data sets into EMS data sets helps patient had been, or currently was, receiving treatment.7–10 ensure a seamless documentation of care from the prehospital Indexed as such, new entries in the medical record, called environment to the emergency department. progress notes, would be placed into the patient’s fi le under Using standardized data sets has tremendous research the problem listed. All healthcare professionals, from physi- potential. With integrated standardized data sets, the effi - cians to nurses to dieticians, would place their entries into the ciency of prehospital interventions can be measured against patient’s record using the SOAP notes format. hospital patient outcomes and recommendations made for The SOAP format may be one of the earliest standardized future practice. documentation formats. With POMR, any allied healthcare To integrate patient information with minimum data sets, provider could open up the patient’s record, called a chart, many EMS systems use a closed form method of documenta- and read what other providers were planning to do, as well as tion. Closed form documents use bubble forms, circles next to review the patient’s progress. With this knowledge in hand, options, which the Paramedic fi lls in to provide information. the provider would make a patient assessment and then enter These bubble forms can then easily be scanned by electronic his or her SOAP note following the last entry. readers to quickly obtain vast quantities of information. The SOAP note would contain subjective (S) information Closed form documents assume most patients will have obtained from the patient or the patient’s family, objective (O) the same or similar complaints, symptoms, and so on, and are information obtained during physical examination, an assess- very restrictive. As a result, many Paramedics complain about ment (A) of the patient’s problem, and a plan (P) for action. their inability to document unique conditions or situations. SOAP notes proved to be invaluable for integrating informa- Many EMS systems use a combined form, one that has tion among a variety of healthcare professionals and ensuring characteristics of a closed form and an open form. These the continuity of patient care. c ombined forms allow rapid information gathering (the Documentation 341 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. minimal data set), as well as the freedom to use some narrative, the patient’s symptoms. The patient’s history consists of an if needed. explanation of the symptoms (i.e., history of present illness) and the patient’s past medical history. CHEATED History of Present Illness Good patient care records paint an accurate picture of the The history of present illness (HPI) is a chronological patient’s condition. For a time, SOAP notes were adequate. description of the development of the patient’s present ill- But as time progressed, Paramedics became increasingly dis- ness, starting with the patient’s chief complaint. If the patient satisfi ed with SOAP notes and started to modify the format to is nonconversational (e.g., because the patient is uncon- include elements unique to EMS. scious), then family and/or bystander comments should be documented. Elements of an HPI typically include location, Early EMS Documentation Formats quality, severity, duration, timing, context, modifying factors, One of the fi rst EMS documentation formats was the CHART and any associated signs or symptoms of the illness. (chief complaint, history, assessment, Rx [prescription], The Paramedic’s intent when gathering a history is to treatment) method. Rather quickly, Paramedics realized develop a symptom pattern. These symptom patterns (i.e., that CHART lacked some needed fi elds, such as an evalua- the list of symptoms) are then compared to the Paramedic’s tion of the interventions. CHART was modifi ed to become knowledge of other diseases, disorders, and syndromes. CHARTIE, adding I for intervention and E for evaluation to When the current symptom pattern matches a symptom pat- the previous information. tern for one of these diseases, disorders, or syndromes, then a Another documentation format that was in common usage diagnosis can be made. is NAP (narrative, assessment, plan of treatment). NAP is a The mnemonic OPQRST (onset, provocation, quality of short documentation format that is particularly well-adapted pain, radiation, severity, timing) is commonly used by Para- for fi rst responder use. Narrative, the N in NAP, is a written medics to help develop a symptom pattern (Table 19-2).11 For description of the patient’s complaints, current history, and any example, the S in the OPQRST stands for severity. Using the physical fi ndings such as vital signs, which is written like a anesthesiologists’ pain scale, the patient is asked to rate the story. Assessment, the A in NAP, is typically complaint driven pain from 0, being no pain, to 10, being the worst pain (e.g., shortness of breath). The plan of treatment, the P in NAP, the patient ever experienced. This line of questioning helps to includes disposition, or to whom the patient was turned over. establish the severity of the patient’s pain as well as establish a baseline to gauge the effectiveness of pain relief. CHEATED Format While a patient history can be endless, the Paramedic To help meet the Paramedic’s needs for a more complete chart- focuses on those questions that will illuminate the cause of ing format, Valerie Conrad, EMS QI Coordinator in Traverse the patient’s problem. It is helpful to have a more structured City, Michigan, developed an EMS-specifi c, user-friendly series of questions for a given problem. documentation method using the mnemonic CHEATED. The Many EMS agencies have adopted the federal Evalua- elements of CHEATED (chief concern/complaint, h istory, tion and Management Documentation Guidelines created examination, assessment, treatment, evaluation, disposition) by the Health Care Finance Administration (HCFA), now contain all of the additional fi elds needed by Paramedics and called the Center for Medicare and Medicaid Services (CMS), is inclusive of the SOAP notes previously used. This docu- and the American Medical Association (AMA). Standardized mentation method is a representation of one effective means histories permit the Paramedic to identify diseases, disorders, of documenting an EMS event. and syndromes, vis-á-vis, through symptom pattern recogni- tion, and document the medical necessity of the therapeutic Chief Concern services provided to the patient. With the standardized history in hand, the Paramedic is The C in CHEATED, chief complaint (CC) or chief concern, now able to establish a diagnosis of the disease, disorder, or is usually the reason that the patient called for EMS. If |
pos- syndrome using the International Classifi cation of Diseases sible, the chief complaint should be stated in the patient’s own (ICD-10) coding system.12–14 words and placed within quotation marks. If the patient is unable to speak, then the reason the patient Table 19-2 OPQRST Mnemonic is unable to speak (e.g., “unconscious”) should be noted. The caller’s words should then be noted. These are the words usu- O Onset, the beginning of the symptoms ally transmitted to the Paramedic by the dispatcher. P Provocation, what started or intensifi ed the symptoms Q Quality of the pain History R Radiation (Does the pain migrate to another body part?) The H in CHEATED, history, contains the subjective infor- S Severity, the intensity of the pain mation provided by he patient, the patient’s family, and/or T Timing (Do the symptoms wax and wane?) bystanders. The subjective information provided is called 342 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. The ICD-10 is the latest edition of the international diag- Starting in a head-to-toe progression, the traditional per- nostic classifi cation system that fi rst started in 1893 as the tinent negatives are loss of consciousness, chest pain, short- International List of Causes of Death. Since that time, the ness of breath, and abdominal pain. Other EMS systems may ICD coding system has evolved and become the standard for add other pertinent negatives as needed. These four pertinent the description and classifi cation of diseases. negatives are ominous if, instead, they are positive. These With the diagnosis made, physicians and administrators conditions typically require advanced life support measures. can group patient populations with the same or similar diag- nosis into diagnosis-related groups (DRG). The original Past Medical History purpose of a DRG was to group patients who used similar Once the HPI is complete, the Paramedic would proceed resources together for reimbursement from Medicare. These to document the past medical history (PMH). To aid with DRG assignments are based on the ICD diagnosis. Currently documentation of the PMH, the Paramedic often uses the the DRG, version 25, also takes into account procedures per- mnemonic AMPLE (allergies, medications, past medical formed as well as the presence of signifi cant comorbidities. history, last meal, events). In the case of EMS, a patient transport might be reimbursed The fi rst element (A) of AMPLE is the patient’s allergies, for respiratory failure, as a DRG, if the patient was intubated. to both prescription and over-the-counter medications. If the The patient may also be reimbursed for obesity, if the patient patient has no allergies to drugs, then the acronym NKDA had that comorbidity. (no known drug allergies) is often used. If the patient has an For a high-priority patient, the Paramedic would obtain allergy to a medication, and time permits, it may be helpful to answers to a minimum of three elements among those listed. get a history of the reaction to determine if it is a true allergy Elements of a history are listed according to body systems in or an unpleasant side effect of the medication. the guidelines. The next element (the M in AMPLE) stands for medica- For a low-priority patient, the Paramedic would obtain a tions. The Paramedic should list all medications— including more detailed history that contains a minimum of six of the prescription, over-the-counter, botanicals, and illicit drugs—by elements listed as well as some past medical history, and/or name, dose, and frequency, if possible. It is appropriate for family and social history. the Paramedic to use standard prescription shorthand to list These minimum standards are used for all patients. The the frequency (e.g., QD for once-a-day). These Latin terms Paramedic’s problem-focused history may elect, based on are listed in the medical terminology chapter. patient condition and clinical judgment, to expand on the history The next item (the P in AMPLE) stands for past medical in order to more completely understand the patient’s condition. history and should include the primary diseases recognized in each major body system (Table 19-3). Again, progressing in a head-to-toe fashion, a minimal past medical history would include questions about strokes and seizures (neurological), Street Smart heart attack and hypertension (cardiovascular), asthma and chronic obstructive pulmonary diseases (COPD) (respira- Special notation should also be made if the patient tory), diabetes (endocrine), and cancers (Ca). If the patient threatens suicide. If possible, the patient’s exact has a preexisting diagnosis for a disease, then that should also be listed. words and the context in which they were said should be noted. It may be the only utterance the patient Review of Systems makes about suicide. A more complete past medical history uses a systems review approach to history gathering. Using a head-to-toe approach, the following systems review represents a more complete Many Paramedics also document any constitutional symptoms noted. Constitutional symptoms are those gen- eral systemic reactions to illness that include fevers, unex- Table 19-3 Example of a Minimal Past plained weight loss, night sweats, chills, headaches, nausea, Medical History and vomiting. Constitutional symptoms can indicate that the • Stroke patient may be infected and the Paramedic should reconsider • Seizure the choice of personal protective equipment (PPE). The HPI typically ends with the patient’s pertinent nega- • Heart attack tives. Pertinent negatives are those symptoms which, if pres- • Hypertension ent, could indicate a more serious underlying problem. There • COPD could potentially be a large number of pertinent negatives, • Asthma but Paramedics tend to limit the pertinent negatives spe- • Diabetes cifi cally to those symptoms that imply pathology in a major • Cancer organ system. Documentation 343 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. history gathering. The systems review can be used as a part include documentation of prior sprains, strains, and fractures, of a comprehensive examination, or portions can be used to especially those that required surgical correction. Often Para- obtain a more complete focused examination. medics also take and document a pain history at this point, Starting at the head, the patient should be asked if he has especially in regard to the prior use of morphine for similar ever had a stroke, seizure, or traumatic brain injury (TBI). If injuries, in anticipation of orders for analgesia. the patient answers affi rmatively to any of these stated con- The Paramedic should document any endocrine disorders ditions, then the Paramedic would use that opportunity to including diabetes, thyroid disorders, and thyroid surgeries. launch into a more extensive line of questioning. For exam- Similarly, any hematological disorders—such as leukemia, ple, if the patient admits to a history of seizures, then the infections, blood transfusions, and overseas travel—should Paramedic could inquire about the frequency of seizures, the be documented. date/time of the last seizure, what medications the patient is If the patient has a behavioral disorder, then the Para- taking for the seizure condition, as well as compliance with medic should document previous psychiatric admissions, any those medications. psychotropic medications, and use of alcohol or illicit drugs. Proceeding to the cardiovascular system, the patient While the review of systems can be exhaustive, the intent should be asked if he ever had angina (chest pain) or a diag- is to discover preexisting medical conditions and then explore nosis of acute myocardial infarction (AMI). If the patient the medical treatments received for those conditions which answers yes, then the Paramedic might inquire which portion might impact on current prehospital care. The previously of the heart was affected. Next, the Paramedic would inquire listed questions in the review of systems merely cites some about angioplasty, including the results and/or a coronary representative questions that could be used. More questions artery bypass graft (CABG). Some patients are so well edu- may be appropriate (Table 19-4). cated about their condition that they can tell the Paramedic The L in AMPLE has various interpretations. It typi- which vessel was involved, the percentage of blockage, and cally stands for last meal. This is an important question if even their last ejection fraction. the patient may be destined for the operating room. Surgeons A review of the respiratory system starts with documen- prefer patients who have not eaten prior to surgery (N.P.O.), tation of any lung disease and often includes smoking history, thereby lowering the risk of aspiration. Some Paramedics also listed in packs/years, and a diagnosis of emphysema. use the L to indicate last bowel movement (if the chief con- The Paramedic should document any abdominal surger- cern is abdominal pain) or last menses (if the patient could ies, including appendectomy, history of small bowel obstruc- have a gynecological problem). Some Paramedics may use tion, and the presence of an abdominal aortic aneurysm, L to mean last time a medication was taken when the patient repaired or not repaired (Figure 19-4). has a known history of epilepsy or diabetes. Proceeding to the genitourinary system, the Paramedic The fi nal element in AMPLE (E) refers to events and should document any history of sexually transmitted diseases. generally is aimed at previous events of the same or similar If the patient is a female, then a reproductive history— including nature and/or other previous encounters with EMS. the number of pregnancies and delivery of newborns—should be documented. A history of kidney stones may also explain Examination fl ank/groin pain and should be documented. The physical examination of the patient, the E in CHEATED, If the patient has an extremity injury, then past medical often starts with the position and condition in which the history of injuries to the extremities, as well as the musculo- patient was found. For example, if the Paramedic fi nds the skeletal system, should be documented. The history should patient with shortness of breath in a tripod position, the Para- medic would note that as part of his general impression and document the same. This type of “from the doorway” assessment is referred to as a constitutional examination. The constitutional examination Table 19-4 Standard Review of Systems • Neurological • Cardiovascular • Pulmonary • Gastrointestinal • Endocrine • Genitourinary • Integumentary • Musculoskelal Figure 19-4 A Paramedic taking a history. 344 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. assesses the patient’s general appearance. Examples of the two extremes of appearance is the patient in extremis, or having great diffi culty, and the patient in no apparent distress (NAD) (i.e., not appearing to be having diffi culty). This “sick–not sick” impression can help the Paramedic establish the tempo of the call. The constitutional examination may also contain objec- tive observations about the patient’s physical development such as “emaciated” or “obese.” These descriptions speak to the patient’s body habitus. For example, the morbidly obese patient typically has a list of medical conditions, such as heart failure and diabetes, associated with being obese. These descriptions of the patient are not slanderous or insulting, but are objective statements which are intended to make an infer- ence about the patient’s health. Similarly, any overt deformities as well as personal grooming habits relate to the patient’s health or the patient’s ability to maintain health. The fi rst sign of Alzheimer’s dis- ease, for example, may be the patient’s inability to perform the activities of daily living, including |
personal grooming. The Paramedic would then proceed to document the fi nd- ings of the initial assessment, including the treatment of any Figure 19-5 Paramedic performing a physical life-threatening injury. examination. Next, the patient’s vital signs are recorded. For blood pres- sure, it should be noted whether it was taken while the patient was supine, seated, or standing. For pulse, regularity (as well as For example, all ECG criteria should be listed (QRS width, rate, respirations, and temperature) should be recorded. etc.) prior to noting an identifi cation of the ECG rhythm. If the patient was high priority, then the Paramedic would Many Paramedics will use a broad label, such as a narrow- document the problem-focused examination fi ndings. The complex tachycardia, and then note a presumptive interpreta- problem-focused examination, sometimes referred to as a vec- tion, such as paroxysmal atrial tachycardia. tored examination, is limited to the affected body area or organ system refl ected in the chief complaint. The various body sys- Assessment tems examined in a problem-focused examination include, While it is important for the Paramedic to accurately and com- from head-to-toe, the neurological system, the cardiovascular pletely describe the patient’s condition, in order to arrive at a system, the respiratory system, the gastrointestinal system, the paramedical diagnosis, it is almost as important for the Para- musculoskeletal system, and the psychiatric exam. medic to consider what is not seen. Documentation showing For example, a problem-focused physical examination consideration of other possible etiologies demonstrates that the for a patient with a complaint of substernal chest pain would Paramedic has an open mind to other potential diagnoses and include the cardiovascular system. Taking a look, listen, and has considered them and then rejected them. This “head’s up” feel approach to physical examination, the Paramedic would attitude helps prevent the Paramedic from focusing too nar- document the presence or absence of jugular venous disten- rowly based on an assumption, without considering other pos- tion and pedal edema. The auscultatory fi ndings, including sibilities. For example, the chest pain experienced by a patient bilateral blood pressures and heart sounds, would be docu- could be due to pulmonary embolism secondary to a deep vein mented. Finally, fi ndings assessed by palpation, such as pedal thrombus. If the Paramedic were to focus exclusively on a car- pulses and the location of the point of maximal intensity diac examination, he might miss the source of the pathology. (PMI), might be documented. Following the discussions of various pathologies in sub- It should be noted that any documentation of the abnormal sequent chapters, the “rule out” or differential diagnosis for without further elaboration is insuffi cient. The assumption is specifi c complaints will be discussed. that the patient has normal fi ndings unless otherwise noted. If the patient is a low-priority patient, then a more detailed Paramedical Diagnosis physical examination would be performed (Figure 19-5). With the history and physical examination documented, the Some Paramedics, especially in trauma cases, prefer a head- Paramedic would proceed to document the assessment. The to-toe approach to the detailed physical examination, whereas assessment is, partly, a protocol-driven medical decision. Typ- others prefer a body systems approach to the examination. ically, for high-priority patients Paramedics use advanced life If an ECG is attached to the documentation, it is important support (ALS) protocols, whereas for low-priority patients that the Paramedic standardize the notation of interpretation. basic life support (BLS) protocols are used. Documentation 345 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. The documentation of the protocol-driven fi eld diagnosis Special Documentation asserts and reinforces the Paramedic’s medical control. If direct contact with medical control is made for purposes of consulta- Several situations are not amenable to standard documentation tion and specifi c orders, then that should be noted as well. procedures. These situations require special documentation or special notations, which will be discussed individually in the Treatment following section. The next section of the PCR is the treatment section. All interventions performed, both BLS and ALS, should be Refusal of Medical noted in the treatment section. If BLS fi rst responders had Assistance Documentation already initiated patient care, then these treatments should The CHEATED format works well for documentation of also be noted in the treatment section, with the notation “per- refusal of medical assistance (RMA). Starting with the chief formed by EMT Jones.” complaint, or chief concern, the Paramedic would document Evaluation the history and the physical examination to the extent permit- ted by the patient. Following every treatment there should be an evaluation of In the assessment section, the Paramedic would address the the effectiveness of that treatment, or, at a minimum, a state- issue of competence, including noting the patient’s age. If the ment about the patient’s ongoing condition. This is the evalu- patient is of age, or is an emancipated minor, then the Paramedic ation phase of patient care. would proceed and document the patient’s mental status. Some have argued that Paramedic care is an unnecessary The key to capacity to consent, or to refuse, is the patient’s expense and that the majority of the Paramedic’s treatments mental status, discussed further in Chapter 6. Any physical or are ineffective, at best. Accurate documentation of the effect medical conditions that would prohibit the patient from con- of prehospital care helps to demonstrate the value of early senting (e.g., intoxication or presumption of stroke) should medical treatments performed by Paramedics. be documented. Actions taken by the Paramedic to enlist the assistance of family, medical control, or law enforcement offi - Disposition cers to convince the patient to seek medical attention should The last section of the CHEATED PCR is disposition. Some be documented as well. Paramedics refer to this as the patient report, a summary of In the treatment portion of the PCR, all treatments per- the patient’s condition and the status of treatments in progress mitted by the patient, including those offered but refused, when patient care was given over to another Paramedic or should be documented. healthcare provider. It is imperative that the Paramedic docu- Instead of completing an evaluation, because treatment ment to whom the patient was turned-over-to (TOT) in order is being refused, the E in CHEATED means explanation of to avoid accusations of patient abandonment. outcomes. The Paramedic should document that the patient The disposition should also contain information about was advised of foreseeable complications that are reasonably the patient’s condition (i.e., changes and improvement), as likely to arise, which could seriously jeopardize the patient’s well as the status of treatments. For example, a Paramedic health and bodily functions or result in a serious dysfunction might document that oxygen was continued, that the IV of an organ or body part if medical attention is refused. remained patent, and state the rate of infusion. The Para- The explanation of outcomes documented should include medic might also want to document the volume of fl uid a list of the symptoms for which the patient should reconsider infused as well as whether blood samples were turned over and recall EMS. Also, the encouragement to seek medical to the emergency department personnel. Finally, the Para- attention from a private physician should be noted. medic may document if the patient was left in the care of Under the fi nal disposition portion, the Paramedic should family, friends, or hospital personnel. document with whom the patient was left and the patient’s ability to summon aid or recontact 9-1-1. The patient should then be asked to sign the completed PCR. A copy of the PCR should be left with the patient, if Street Smart possible. Some EMS systems use special documentation forms for refusals of medical care. If the patient is unwilling After the patient is transferred from the ambulance to sign the PCR, the Paramedic should note the refusal and gurney to the hospital stretcher, the side rails on obtain the names, and signatures, of witnesses. the stretcher should be raised unless the patient is Hazardous Materials attended to by a hospital staff member. “Side rails up Operations Documentation times two” is often the fi nal line of documentation on Key to hazardous materials operations documentation is an the PCR. understanding that such documentation may be called into play in lawsuits and disability hearings years after the patient 346 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. was seen by the Paramedic. Complicating matters, the aver- proceed to ask about inherited risk factors, personal habits age hazardous materials technician being assessed by EMS (such as smoking or alcohol use), as well as document a sys- may not have any signifi cant complaints and yet is given an tems review of the patient’s health. When the prenatal ques- on-scene physical examination as a part of the process of tionnaire is completed, the Paramedic would document the decontamination. patient’s pregnancy history, including past diffi culties with Using the CHEATED format in this venue, the Paramedic delivery. should document, under chief complaint, the exact potential chemical exposure, or exposures, if known. Under the his- Special Incident Report tory section, the Paramedic should explain the circumstances which caused the exposure. Many Paramedics are asked to complete documentation A standard well-person physical examination, includ- that is not directly related to patient care. These documents, ing vital signs, should be documented. Many EMS systems that can be broadly termed special incident reports (SIR), also perform a baseline cardio-thoracic examination for later are used for administrative purposes or as a part of a court comparison. proceeding. The patient’s assessment and treatment are usually based One special incident report is an exposure report. upon prewritten protocols. The Paramedic should docu- The exposure report, separate from the patient care report ment if the patient’s physiological condition meets or fails to that should be generated for each individual who was seen meet those parameters and if treatment is indicated. In some after exposure, details the circumstances that resulted in instances, the treatment is limited to what is typically offered the Paramedic being exposed. The intention of an expo- in a fi re rehabilitation sector. sure report is to identify the problem and then correct the Finally, the patient’s disposition, such as discharged to problem so that another exposure cannot occur. Therefore, rehabilitation, discharged to home, or transported for further names of exposed individuals may not be needed on the evaluation, should be documented. report. Under most circumstances, the designated offi - cer (DO) for the agency receives the exposure report and Documentation of Multiple Casualties would make recommendations for corrections to prevent problems in the future. Understandably, Paramedics cannot take the time to perform In most states, Paramedics are considered mandatory standard documentation during a mass casualty incident. In reporters of child abuse and are required to complete a stan- those circumstances, the triage tag is the only documentation dardized reporting form. This type of report would be con- that will be performed. sidered a special incident report. Similar forms may also be At the end of the incident, the Paramedics should com- available for reporting domestic violence or elder abuse. plete an event report that details, like the hazardous materials incident report noted previously, the situation and conditions that occurred which led to the mass casualty incident. The Legal Proceedings event report should be as detailed as possible. The triage tags When a Paramedic has been a witness to a crime, or is a are then attached to the event report as a part of the perma- named party to a claim of negligence, the Paramedic may be nent record. called |
upon to provide special documentation.17–20 In some cases, human error may have contributed to the Some attorneys, or legally authorized persons, may only incident and charges of negligence may be brought against request that the Paramedic make a legal sworn statement, those individuals who are believed to be responsible.15–16 In called an affi davit, about the events surrounding an incident. that situation, the Paramedic may subsequently be called to These statements are voluntary and typically witnessed by a testify about the conditions on-scene as well as the patient notary public. care provided. During the discovery phase of a trial, discussed in Chap- Documentation of Pregnancy ter 6, the Paramedic may be requested to give a deposition. A deposition is the testimony of a witness (in this case, a and Childbirth Paramedic) in a setting outside of a court, where attorneys Standard EMS documentation is designed to document the from both parties can interrogate the witness. The sworn tes- condition of an ill or injured person. The pregnant woman timony given by the witness is recorded by a stenographer. is neither ill nor injured. The wellness examination of the A transcript, a word-for-word account, is then produced for pregnant woman focuses on documenting the state of the use in the lawsuit and may be submitted into evidence in a pregnancy as well as identifying potential complications of court of law. Often Paramedics rely on the PCR or a SIR to childbirth. refresh recollection or for background information regarding Starting with a prenatal questionnaire, the Paramedic the case. should document the answers to the questions about this preg- In some cases, the attorney may elect to have the Para- nancy, such as date of last menstrual period (LMP) and/or the medic answer questions in a written deposition, in a manner expected date of delivery (EDD). The Paramedic should then similar to an affi davit. This is discussed further in Chapter 6. Documentation 347 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Documentation is an important aspect of EMS. The quality of patient care, and the Paramedic’s professionalism, is often refl ected in the patient care report. The benefi cial nature of a patient care report is a function of its ability to communicate the message that the sender (the Paramedic) intended for the receiver (the emergency physician). By learning the correct medical terminology and abbreviations, and reporting thoroughly but concisely while utilizing a charting format consistently, the Paramedic can expect success with her documentation. Key Points: • The fi rst purpose of documentation is to use it as a • Specifi c protocols should be in place to resolve medical record. errors and omissions. • The patient care report is also used for quality • In an electronic age, safeguards must be in place to assurance and performance improvement. ensure patient privacy from unwarranted invasion. • The PCR is also a business record used to bill • While many documentation formats exist, federal and state governments as well as private Paramedics should choose the one that meets their insurance. agency’s needs and provides the most complete • documentation of the events that transpired. The PCR is a legal document used in litigation. • • Special events, such as hazardous materials Documentation standards help to ensure that the incidents or multiple casualty incidents, require a standard of care was met. special incident report. Review Questions: 1. What are the six reasons cited for documenting 6. Defi ne “pertinent negatives.” patient care? 7. What are the minimum elements required for a 2. What is meant by the phrase “prudent layperson refusal of medical assistance? standard”? 8. What are the minimum elements required for 3. What are the accepted practices for documenting patient care for responders at the documenting errors and omissions? scene of hazardous materials operation? 4. How does the federal Health Insurance 9. What is the documentation tool used at a Portability and Accountability Act (HIPAA) multiple casualty incident and what are the affect documentation? fi elds required? 5. List three documentation formats and provide 10. What are the different legal instruments used at details for one of them. a legal proceeding? 348 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Case Study Questions: Please refer to the Case Study at the beginning of the 2. How is the patient care report used for chapter and answer the questions below: performance improvement? 1. Why is accurate documentation of a cardiac 3. Medically, what use does a physician have for a arrest important? Paramedic’s patient care report? References: 1. Shah R, Geisler CD, et al. A study of hospital based ambulance news_and_articles/columns/Edgerly/Assessing_Your_ systems in Wisconsin. J Clin Eng. 1979;4(3):275–281. Assessment.html Accessed May 16, 2009. 2. Belding J. Patient refusal. What to do when medical treatment & 12. Cimino JJ. Review paper: coding systems in health care. transport are rejected. Jems. 2006;31(5):116–118. Methods Inf Med. 1996;35(4-5):273–284. 3. Goldberg RJ, Zautcke JL, et al. A review of prehospital care 13. Alexander S, Conner T, et al. Overview of inpatient coding. Am litigation in a large metropolitan EMS system. Ann Emerg Med. J Health Syst Pharm. 2003;60(21 Suppl 6):S11–S14. 1990;19(5):557–561. 14. Watzlaf VJ, Garvin JH, et al. The effectiveness of ICD-10-CM 4. Stapczynski JS. Is the prudent layperson standard really a in capturing public health diseases. Perspect Health Inf Manag. “standard”? Ann Emerg Med. 2004;43(2):163–165. 2007;4(6):6. 5. Johnson LA. Coverage disputes and the prudent layperson 15. Zoraster RM, Chidester C, et al. Field triage and patient standard. Ann Emerg Med. 2004;44(4):426; author reply maldistribution in a mass-casualty incident. Prehosp Disaster 426–427. Med. 2007;22(3):224–229. 6. Davis, N, et al. Practice brief. Facsimile transmission of health 16. Risavi BL, Salen PN, et al. A two-hour intervention using information (updated). J Ahima. 2001;72(6):64E–64F. START improves prehospital triage of mass casualty incidents. 7. Rakel RE. The problem-oriented medical record (POMR). Am Prehosp Emerg Care. 2001;5(2):197–199. Fam Physician. 1974;10(3):100–111. 17. Nagorka FW, Becker C. Immunity statutes: how state laws 8. Silfen E. Documentation and coding of ED patient encounters: protect EMS providers. Emerg Med Serv. 2005;34(6):93–94, an evaluation of the accuracy of an electronic medical record. 96–97. Am J Emerg Med. 2006;24(6):664–678. 18. Wiggins CO. Ambulance malpractice and immunity. Can a 9. Bossen C. Evaluation of a computerized problem-oriented plaintiff ever prevail? J Leg Med. 2003;24(3):359–377. medical record in a hospital department: does it support daily 19. Maguire BJ, Porco FV. An eight-year review of legal cases clinical practice? Int J Med Inform. 2007;76(8):592–600. related to an urban 9-1-1 Paramedic service. Prehosp Disaster 10. Sandlow LJ, Bashook PG, et al. Gradual acceptance of POMR. Med. 1997;12(2):154–157. Internist. 1980;21(3):6–7, 17. 20. Colwell CB, Pons P, et al. Claims against a Paramedic ambulance 11. Edgerly D. Assessing your assessment. Journal of Emergency service: A ten-year experience. J Emerg Med. 1999;17(6): Medical Services on-line. Available at: http://www.jems.com/ 999–1002. Documentation 349 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. The fi nal section of this volume includes the essential material in airway management, monitoring devices, intravenous access, pharmacology and ECG monitoring and acquisition that forms the basis for Paramedic assessment and treatment. This section provides the foundation for the clinical chapters in Volume II. • Chapter 20: Airway Anatomy and Physiology • Chapter 21: The Algorithmic Approach to Airway Management • Chapter 22: Non-Intubating Airway Management • Chapter 23: Intubating Airway Management • Chapter 24: Medication-Facilitated Intubation • Chapter 25: Ventilation • Chapter 26: Principles of Medication Administration • Chapter 27: Intravenous Access • Chapter 28: Blood Products and Transfusion • Chapter 29: Introduction to Pharmacology • Chapter 30: Pharmacological Interventions for Cardiopulmonary Emergencies • Chapter 31: Pharmacological Therapeutics for Medical Emergencies • Chapter 32: Principles of Electrocardiography • Chapter 33: The Monitoring ECG • Chapter 34: Diagnostic ECG—The 12 Lead 351 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. KEY CONCEPTS: Upon completion of this chapter, it is expected that the reader will understand these following concepts: • The route an oxygen molecule takes from the oral or nasal cavities to the alveolar capillaries • Anatomy of airway structures as viewed with a laryngoscope • Lung volumes/capacities and mechanisms for negative pressure ventilation • Composition of air and the physiology of the internal and external exchange of respiratory gasses • Key anatomical differences between the pediatric and adult airway and respiratory physiology Case Study: A Paramedic student is presented with a 120 kg patient who had a sudden onset of diffi culty breathing while sleeping. The patient had a history of congestive heart failure and high blood pressure. The patient states he has had increased swelling in his legs over the past two days and sleeps with several pillows because of diffi culty breathing while lying fl at. The physical exam reveals increased work of breathing with diminished lung sounds in bases and diffuse rales. The student’s treatment plan includes oxygen therapy, a breathing treatment, nitroglycerin, and furosemide. As the patient does not improve, the Paramedic student places the patient on continuous positive airway pressure (CPAP). 352 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Airway Anatomy and Physiology 353 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. OVERVIEW Assessing the patient’s airway is a fundamental part of any initial patient assessment. Therefore, interventions may be needed to open and secure the airway or assist with ventilations. The act of breathing transports air entering the oral or nasal cavities to the alveolar sacs where gas exchange can occur. This chapter will examine the anatomy of the adult and pediatric airway and the physiology of each component. The Paramedic should have knowledge of how an oxygen molecule is transported from the oral or nasal cavities to the alveolar capillaries. When performing |
advanced airway procedures, every Paramedic must possess an intimate knowledge of a patient’s airway anatomy and respiratory physiology. Although minor individual anatomic variations exist, every patient will have a similar anatomic structure and respiratory physiology. If the Paramedic has a clear understanding of normal airway anatomy and ventilation, he can maximize his interventions and greatly improve his chances of successful airway management. Airway Anatomy addition of 1 L of fl uid produced by glandular secretion and transudation, or liquid diffusing across the mucous membrane The airway is divided into the upper and lower airway into the nasal cavity. This fl uid not only serves to humidify (Figure 20-1). The upper airway begins at the nares and mouth the air entering the lungs but also has signifi cant antibacterial and extends to the glottis. The lower airway extends from the properties. In addition, large particulate matter is fi ltered via glottis to the alveoli. The respiratory system is composed of the nasal hairs and trapped in mucus. The area is also served many other structures including a number of ligamentous, by extensive lymphatic drainage.1 Anatomically, the passage muscular, and bony structures in the neck and chest. The from the nare to the nasopharynx is a straight line parallel to following section will look at each of these components and the roof of the mouth. Knowing this anatomy is important their role in both ventilation and airway management. prior to the placement of such devices as nasotracheal tubes, nasopharyngeal airways, and nasogastric tubes. The Upper Airway The nasopharynx lies posterior to the turbinates and The openings of the mouth and nose defi ne the beginning superior to the soft palate. It terminates into the oropharynx of the airway. From a functional perspective, the nose is inferior-posteriorly. The pharynx is the area of the airway the primary structure for air entrance. The nose provides an composed of the spaces behind the nose (the nasopharynx) immunologic barrier (mucus), warms and humidifi es air, and and the oral cavity (the oropharynx). serves as a threat/food detection system (sense of smell). This When the facial bones and the bones of the skull develop compact unit allows an individual to simultaneously eat and in the fetus, small air pockets called “sinuses” form. These breathe. In times of high ventilatory demand (e.g., exercise, sinuses are attached to the main airway passages and thus fear, pulmonary disease) or instances when the nares are normally have an internal pressure equal to atmospheric blocked, a person can also utilize the mouth for ventilation. pressure. The sinuses are lined with mucous membranes and Air enters the nares and immediately passes along may have a role in trapping bacteria. In addition, the weight the turbinates (Figure 20-2). The nasal fossae are divided savings of replacing bone with air make the skull signifi cantly by the septum—a midline cartilaginous structure. In the lighter. The walls of the sinuses are thin and easily fractured. average adult the fossae extend approximately 12 cm to the Given their locations, fractures of certain sinuses may allow nasopharynx and, due to folds in the mucosa, each fossa a direct connection from the inside of the skull to the exterior provides approximately 60 cm2 of surface area for fi ltration, world, particularly in the case of a basilar skull fracture. warming, and humidifi cation.1 This heavily vascularized Despite occasionally serving as a passage for air, the mucosa is composed primarily of ciliated columnar cells mouth is much less suited for the processes of ventilation and goblet cells. Relatively minor trauma (e.g., insertion than is the nose. The mouth does not have the nose’s ability of a nasopharyngeal airway) can result in signifi cant to provide and maintain humidifi cation and is not as well hemorrhage. equipped to serve as a particulate/pathogen fi lter. Nonetheless, For an average-sized adult with normal ventilatory the Paramedic must be cognizant of the mouth’s structures function, approximately 10,000 liters (L) of air pass through as the oropharyngeal route is the most common route for the nasal fossae each day. This air is humidifi ed through the assisted airway management. The oral cavity is bound by 354 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Sinuses Nasal cavity Upper respiratory system Mouth Pharynx Epiglottis Larynx Right lung Trachea Bronchus Lower Pulmonary vein respiratory Pulmonary artery system Cut edge of parietal pleura Bronchiole Cut edge of diaphragm Bronchial artery Alveoli Bronchiole Pulmonary arteriole Pulmonary venule Figure 20-1 Overall respiratory system anatomy. Nares Nasopharynx Hard palate Soft palate Oral cavity Uvula Tongue Oropharynx Larynx Epiglottis Thyroid cartilage Cricoid Esophagus cartilage Trachea Figure 20-2 Upper airway anatomy. Airway Anatomy and Physiology 355 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. the lips anteriorly, the buccal surfaces (cheeks) laterally, vasculature of the mucous membrane make this a high-risk area the tongue inferiorly, the hard palate superiorly, and the soft for bleeding during airway management. In addition, during palate posteriorly (Figure 20-3). The tongue occupies much times of pharyngeal or oral infections, these tissues can swell of the oral cavity and, as a muscular structure, can move freely and actually occlude the airway. Therefore, they may preclude throughout the cavity. standard orotracheal airway management practices. The lower jaw, or mandible, articulates with the temporal The pharynx and hypopharynx are the areas of common bones at the temporomandibular joints. The mandible is able passage for food and respiratory gasses (Figure 20-1). The area to move inferiorly and superiorly (i.e., mouth opening and clo- contains numerous structures including multiple constrictor sing), laterally (i.e., moving side to side), and anteriorly (i.e., and elevator muscles to aid in swallowing. The epiglottis “jaw jutting”). The temporomandibular joint is relatively loose also resides in this space. The hyoid bone, another structure and the ball of the joint can move partially out of its socket to of importance in this region, is the only bone in the body allow greater opening and anterior movement. Diseases that that does not directly articulate with another bone. Instead, affect the temporomandibular joint decrease mouth opening it serves as a common point of attachment for a number of and can make airway management more diffi cult. muscles and ligaments that function in swallowing and airway The average adult has 32 teeth—16 upper and 16 lower. maintenance. The hyoepiglottic ligament is one such structure Through disease, wear, and trauma, the teeth may become that will be discussed in more detail in the following text. Other loose or may be replaced by appliances. The teeth and these attachment points include the mandible, the styloid process of appliances (e.g., dentures, partials, etc.) give the lips and the skull, the posterior skull, the sternum, the scapula, and the cheeks structure and help the Paramedic maintain an adequate thyroid cartilage, making the hyoid a critical anchor point for face seal during ventilation. During intubation, however, teeth many physiologic functions (Figure 20-4). can impede the view of the lower airway structures. Thus, The epiglottis is one of the most important anatomic and dental appliances should be removed before intubation. physiologic structures of the upper airway. This “U” shaped The tonsillar pillars that form the walls of the oropharynx structure composed of fi broelastic cartilage is attached to the are composed of lymphatic tissue (the palatine tonsils) and anterior pharynx between the base of the tongue and the larynx. the muscles used for swallowing. Along with a ring of other Although considered by some to be vestigial,2 the epiglottis lymphoid tissue, these structures serve as an immunological seems to serve a function in protecting the lower airway from barrier to pathogen entry in the pharynx. The palatine tonsils foreign body aspiration. It is covered by a mucous membrane deserve special mention for the Paramedic. As with the rest of that is contiguous with the tongue. The space formed between the upper airway, these structures are covered by a thin mucous the anterior-superior surface of the epiglottis and the posterior membrane. The prominence of the palatine tonsils and the base of the tongue is the valecula. The epiglottis is attached to the midline of the thyroid cartilage by the thyroepiglottic ligament. Given its size, contents, and multiple functions, the pha- Upper lip rynx is a very common area for airway obstruction to occur. Traditional teaching has suggested that the tongue falls posteriorly in the obtunded patient and obstructs the airway. However, imaging work by Shorten et al.3 has demonstrated that, in fact, the soft palate and epiglottis make contact with Hard palate the posterior wall of the oropharynx and pharynx before the tongue does and that these structures cause airway obstruction. Soft palate Thus, the action for opening an airway actually depends on Uvula the anterior traction on the epiglottis. This is accomplished Tonsil through the hyoepiglottic ligament by the anterior displacement Pharynx of the hyoid bone. The hyoid is lifted by anterior mandibular displacement (the hyoid has multiple muscular attachments Tongue to the mandible) that occurs with a head-tilt chin-lift or jaw thrust. The Lower Airway The visible structures of the lower airway (Figure 20-5a) can be seen by the Paramedic during orotracheal intubation. The larynx, also known as the “voice box,” is the upper group Lower lip of structures of the lower airway and opens with a number of cartilaginous structures. From anterior to posterior, these structures include the base of the epiglottis, the thyroid Figure 20-3 The oral cavity. cartilage, and the aryepiglottic folds (Figure 20-5b and 356 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Stylohyoid Mandible muscle Mylohyoid muscle (severed) Digastric muscle Digastric muscle (posterior belly) (anterior belly) Thyrohyoid muscle Geniohyoid muscle Hyoid bone Omohyoid muscle Stylo p h a r yngeus muscle Thyroid cartilage Cricoid cartilage Sternothyroid muscle Sternohyoid muscle (partially severed) Figure 20-4 The hyoid bone and its muscular attachments. Figure 20-5c). The aryepiglottic folds contain three separate apple” in men as well as a lower pitched voice.1 The posterior cartilaginous structures: the cuneiform, corniculate, and margins of the thyroid cartilage terminate in the superior arytenoid cartilages (from anterior to posterior). These and inferior thyroid horns or cornu.4 The superior horns are structures are attached to each other and other structures by attached to the hyoid via the thyrohyoid ligament and the ligaments as well as the intrinsic and extrinsic muscles of the inferior horns articulate with the cricoid cartilage via a true larynx. The whole complex is covered by mucosal folds. synovial ball and socket joint similar to the hip joint. The open space below the laryngeal opening and superior to the vocal cords is called the vestibule. Small outpouchings in Street Smart the mucosal folds that overlie the vestibular membrane of the quadrangular membrane form the false cords. The false cords, which do not serve in phonation (the production of speech and The arytenoids are the posterior-most structures sound), are important because they can seal over the glottis to of the laryngeal opening. Any endotracheal tube help protect the airway from aspiration of foreign materials. visualized passing anterior to the arytenoids is, The vocal cords are visible at the bottom of the vestibule. As with other structures of the larynx, the vocal cords are by defi nition, passing |
into the larynx and trachea, composed of mucosal folds overlying ligaments, cartilages, even if the cords are not visualized. Any tube and muscles. The cricothyroid ligament starts anteriorly as visualized passing posterior to the arytenoids is the cricothyroid membrane that attaches the cricoid ring to in the esophagus. the thyroid cartilage. The thickened central portion of the cricothyroid membrane, called the “conus elasticus,” extends to the interior border of the thyroid cartilage and then turns The thyroid cartilage is the large, anterior shield-like posteriorly, splitting in half and attaching on the arytenoid cartilage structure that forms the majority of the anterior cartilages. The medial edges of this portion of the cricothyroid portion of the larynx. It is attached superiorly to the hyoid via ligament thicken and are called the vocal ligaments. With the thyrohyoid membrane and inferiorly to the cricoid ring by their associated mucosal folds, the vocal ligaments form the the cricothyroid membrane. From its anterior, superior midline true vocal cords. These structures are typically found at the notch, the thyroid cartilage extends laterally and posteriorly level of the 5th cervical vertebrae in an adult. to form a “half-pipe” shape. In females, the thyroid cartilage The vocal cords serve two main functions in the airway. is fl atter than in males, resulting in a more prominent “Adam’s The fi rst is phonation. The extrinsic and intrinsic muscles of Airway Anatomy and Physiology 357 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Thyroid cartilidge vocal cords are abducted (moved away from each other) to maximize laminar (linear, nonturbulent) airfl ow. In the cadaver (and in paralyzed patients who have lost laryngeal Cricoid Glottis cartilage muscular function), the resting position of the vocal cords is abducted and “loose” or “wavy” appearing. Vocal ligament The second function of the vocal cords (the glottis) is airway protection. The muscles that produce phonation can also adduct the glottis and the false cords to provide an impenetrable barrier to foreign material. The stimulation Superior horn of the thyroid of nerve endings in the supraglottic region (the vestibule) cartilage triggers a short-lived involuntary refl ex resulting in glottic (a) closure. A number of stimuli including touch, temperature, and chemicals can trigger this refl ex. If the glottis remains Epiglottis closed, it is called laryngeal spasm and can make airway management challenging. Hyoid bone Thyrohyoid membrane Street Smart Thyroid cartilage Cricothyroid ligament Most laryngospasms will resolve with positive pressure ventilation, timed with the patient’s natural Cricoid cartilage inspiration. If that does not succeed, then chemical Trachea paralysis or a rapid surgical airway may be required in (b) order to oxygenate the patient. Epiglottis Body of The remaining cartilaginous structure of the larynx is the cricoid ring (Figure 20-5b). The cricoid ring, the only Thyrohyoid hyoid bone membrane Thyroid complete ring in the trachea, is located at the lowest portion membrane of the larynx and the beginning of the trachea. The widest Cuneiform cartilage Fatty pad part of the ring is found posteriorly and rises toward the Corniculate cartilage arytenoids. The cricoid ring supports the larynx above it Vestibular fold Arytenoid cartilage (false vocal chord) and is attached by a number of ligaments; the tracheal rings Arytenoid muscle are attached inferiorly by many muscles and ligaments. The (controls swallowing) Thyroid cartilage complete nature of the ring makes it susceptible to fractures. Cricoid Vocal fold Conversely, properly applied cricoid pressure allows the cartilage (true vocal chord) ring to compress the esophagus, essentially sealing off the Tracheal cartilages Cricothyroid esophagus and minimizing the risk of regurgitation. ligament Cricotracheal ligament (c) Street Smart Figure 20-5 a-c Laryngeal anatomy. (a) As Many well-intentioned individuals, in attempting to viewed during laryngoscopy. (b) From an anterior view. (c) From a lateral view. apply “cricoid” pressure, actually go for the largest structure visible/palpable and apply “thyroid” the larynx move the various cartilages to change the shape (cartilage) pressure. Not only does this not necessarily and tension of the cords. The intrinsic muscles are most occlude the esophagus, but pressure on the thyroid responsible for the modifi cation of the cords. The changes in cartilage at its middle to inferior margin causes the shape and tension allow the full vocal range. The innervation of the intrinsic muscles is primarily from the recurrent vocal cords to rise anteriorly, making them more laryngeal nerve. On phonation, the vocal cords are adducted diffi cult to visualize during laryngoscopy. (brought together) to produce sound. On inspiration, the 358 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Other important structures of the larynx include the There are a number of clinically signifi cant structures intrinsic and extrinsic laryngeal muscles and their nerve external to the laryngeal airway (Figure 20-6). These supply. These muscles were previously described in terms structures are of importance to the Paramedic both because of their function. Although knowledge of the individual of their potential for injury during airway management and muscles, their individual innervation, and their individual because, if injured, whether by the Paramedic or during a function is not critical to the Paramedic, understanding the traumatic event, they can cause compromise of the airway. overall function in terms of laryngeal movement, phonation, The thyroid gland is a highly vascular “H” shaped and airway protection is important. Of particular importance structure that lies along the sides of the larynx and upper is the “gag refl ex.” This refl ex arc depends on sensory nerves trachea. The crossbar of the “H” crosses the trachea just at the level of the oropharynx, the pharynx, and the larynx below the cricoid ring. A laceration of the thyroid will lead to trigger the response. The refl exive response is coughing to signifi cant bleeding. In addition, disease of the thyroid can and coordinated activity by the muscles of the hypopharynx, result in swelling and deformation of the airway anatomy. oropharynx, and pharynx to propel the offending stimulus Two sets of major vascular structures—the common into the mouth and out of the body. carotid arteries and the internal jugular veins—run parallel Hyoid bone Thyrohyoid membrane Superior laryngeal artery Superior thyroid artery Thyroid cartilage Posterior branch, superior thyroid artery Median cricothyroid ligament Anterior branch, superior thyroid artery Cricoid cartilage Common carotid artery Cricothyroid branch, superior thyroid artery Internal jugular vein Vagus nerve and its superior cardiac branch Ventral branches of C4 to C8 nerves Subclavian artery Ventral branch of T1 nerve Cupula of pleura; Subclavian vein ansa subclavia and lymphatic trunk Phrenic nerve Esophagus; thyroid Phrenic nerve; venous plexus; left pericardiacophrenic artery recurrent laryngeal nerve Figure 20-6 Superfi cial anterior neck anatomy. Airway Anatomy and Physiology 359 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Terminal of an epithelial layer, mucous glands, lymphatic tissue, nerves, bronchiole vascular structures, and structural cartilage. The most common cell in the large lower airways is the ciliated epithelial cell. The cilia (small hair-like projections) form the moving portion of the “mucociliary” escalator. The mucus secreted by goblet and serous cells traps small particles and pathogens. The cilia move the mucus up the airway into the hypopharynx where the secretions are swallowed and digested. The lymphatics also Trachea serve to move trapped pathogens to the lymph nodes so the Bronchi immune system may deal with them. Mucous glands are seen Bronchiole through the lower airway to the level of the smallest bronchi; they are not seen in the alveoli. At the level of the carina, the lower airway splits into the two mainstem bronchi—called the right mainstem bronchus and left mainstem bronchus. The two bronchi are angulated equally until age 3, when the right mainstem bronchus becomes more acutely angled. This acute angle predisposes endotracheal tubes, suction catheters, and foreign bodies to enter the right mainstem bronchus. The right mainstem Carina bronchus is larger in diameter than the left and divides into three lobar bronchi. The left mainstem bronchus separates into two lobar bronchi. These lobar bronchi further subdivide into medium bronchi. The walls of the bronchi are similar in structure and function to the walls of the trachea. They are composed of the same layers with equivalent functions. The posterior (non-cartilage containing) portion of the bronchial wall has its attachment points within the ring of cartilage rather than attaching the ends of the cartilage rings; during inspiration, the posterior wall of a bronchus will collapse further into the lumen than the posterior wall of the trachea does. At the level of the medium bronchi, the rings of cartilage become plates of cartilage that allow for a more symmetric contraction of Alveoli the airway lumen. At a diameter of less than 0.8 cm, the bronchi are called bronchioles. At less than 0.6 cm, the cartilage plates disappear as well, leaving structures held open only by elastic fi bers and the muscles of the bronchial walls. Although the muscles Figure 20-7 Lower airway anatomy. continue to thin out as the airway diameter decreases, they do so at a slower rate than the rate at which the airway diameter decreases. Therefore, the muscles of the terminal bronchioles to the pharynx. The carotid arteries are the major suppliers of are proportionately larger compared with the diameter of the blood to the brain while the internal jugulars return most of airway. They are more capable of closing off the airway when the cerebral blood to the heart. Bleeding from these structures bronchial spasm occurs than are the muscles of the larger can result in signifi cant deformity of the airway. Additionally, bronchioles or bronchi. injury to the carotids compromises blood fl ow to the brain A terminal bronchiole ends in the acinus, or a sac-like part and can result in cerebral hypoxia or anoxia. of the lung supplied by a single terminal bronchiole. Alveoli The trachea is a conduit for respiratory gasses. In an adult, may branch off of the bronchiole at this level. However, it is 10 to 20 cm long and 1 to 1.5 cm in diameter. Its superior the ends of the terminal bronchioles are the alveolar ducts attachment is the cricoid ring (level of the 6th cervical vertebrae) that open into the alveolar air sacs. The alveolar sacs open and it terminates at the carina (level of the 5th thoracic into large collections of alveoli (single units being called vertebrae) (Figure 20-7). The cartilage rings of the trachea are alveolus). This large collection of smaller sacs provide a incomplete, with the posterior element void of cartilage and larger surface area for gas exchange than if the lung were composed of muscle and elastic fi bers.5 The muscles of the made up of a single large sac (Figure 20-8). Although the trachea include an inner circular layer and an outer longitudinal trachea is the largest lower airway structure and the alveoli layer. The walls of the trachea (and the bronchi) are composed the smallest, each successive airway structural level (main 360 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the |
right to remove additional content at any time if subsequent rights restrictions require it. Exhaled CO Inhaled O 2 of the thorax consist of the thoracic vertebrae, the rib cage, 2 the sternum, the clavicles, and the scapulae (Figure 20-9). Entering The clavicles and scapulae are not directly responsible for capillary Leaving ventilation but serve as accessory anchoring points for either with CO2 capillary accessory muscles or for muscles that support the rib cage. with O2 The thoracic vertebrae are articulation points for the 12 ribs and form the posterior bony border of the thoracic cavity. The thoracic vertebrae typically do not move during respiration. The exception to this occurs during highly active breathing when an individual leans forward during expiration and then extends the spine and stands straight during inspiration. The ribs, however, do move and articulate with the transverse processes of the thoracic vertebrae. The sternum is a dagger- shaped bone that attaches to the clavicles and the ribs. It is the anterior-most bony structure of the thorax and provides structural support to the ribs during respiration. The rib cage is the primary bony structure of respiration. Composed of 12 matched pairs of curved bones, the rib cage acts to protect the thoracic structures and serves as the fulcrum for the intercostal muscles of respiration. The ribs are numbered 1 through 12 and articulate posteriorly with their similarly numbered thoracic vertebrae. Anteriorly, the ribs are attached to the sternum by the costal cartilages. Ribs 1 to 7 are considered “true” ribs in that each has its own Figure 20-8 An acinus is composed of many costal cartilage that attaches it to the sternum. Ribs 8 to 12 alveoli and is surrounded by a capillary bed. This are considered “false” ribs. Ribs 8, 9, and 10 are attached to is where the exchange of oxygen and carbon the sternum through a common costal cartilage; the cartilages dioxide occurs. from each of the rib tips merge into a single cartilage that is attached to the sternum. Ribs 11 and 12 are called “fl oating ribs” because, although they are attached to other ribs via the bronchi, lobar bronchi, etc.) increases the number of struc- intercostal musculature and serve in respiration, they only tures and, with it, the cross-sectional area of the airway. articulate posteriorly on the thoracic vertebrae and are not Therefore, with 500 million alveoli in the average adult lung, directly attached to the sternum via a costal cartilage.6 the cross-sectional area of the alveoli is 350 thousand times The muscles of respiration can be divided into the principal greater than the cross-sectional area of the trachea. This high and accessory muscles of inspiration and the active muscles cross-sectional area allows for massive gas exchange, which of expiration. During quiet breathing, without pathologic occurs by diffusion. The surfaces of the alveoli are covered with surfactant, a fl uid that decreases the alveoli’s surface tension and prevents them from collapsing during expiration. The surfactant holds the alveoli open and prevents atelectasis (collapse of the alveoli and loss of gas exchange surface). Premature infants and drowning victims who aspirate water may have inadequate Sternocleidomastoid surfactant to prevent atelectasis, leading to signifi cant hypoxia muscle and ventilatory failure. The remainder of the lungs not occupied by the airway Apex of lung Upper lobe structures and blood vessels (the lung parenchyma) is right lung Upper lobe composed primarily of structural support and immune left lung structures. The supporting structures are important during the Middle lobe mechanical act of respiration. right lung Lower lobe Bony Thorax Anatomy Sternum left lung Base of Lower lobe lung The bony anatomy of the thorax not only provides protection right lung to the thoracic organs and major blood vessels, but also Diaphragm produces the air pressure difference responsible for air movement in and out of the respiratory system. The bones Figure 20-9 The bony thorax. Airway Anatomy and Physiology 361 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. derangement, the principal muscles of inspiration drive bag. Since the bottle is on the outside of the bag, there are inspiration while passive recoil of the chest wall and lungs two layers of the bag underneath the bottom of the bottle. If drives expiration. During active breathing (e.g., with heavy the bag is then lifted up around the bottle, there will be two activity or disease), the accessory muscles of inspiration are layers of garbage bag all around the bottle. Finally, the bag is recruited, as are the active muscles of expiration. Knowledge collected at the neck of the bottle and attached with a rubber of the normal muscles of quiet breathing is critical to band. The end result is a bottle inside of a two-layered bag. understanding respiratory physiology (Figure 20-10). The layer of the bag against the plastic bottle represents the One muscle and a major muscle group contribute visceral pleura and the outside layer of plastic represents the to inspiration. The fi rst and largest muscle involved in parietal pleura. The sealed area at the neck of bottle represents inspiration is the diaphragm. This large, thin, dome-shaped the way the pleura seals against the bronchi as they leave the muscle divides the abdomen from the thorax. At rest, the lungs. In the body, the visceral and parietal pleura lie against diaphragm rises to the level of the 5th rib (approximately each other with a small amount of fl uid between them. This the level of the nipple). During inspiration, the diaphragm allows them to slide against each other but not to pull apart contracts and fl attens. Since the margins of the diaphragm from each other. are fi xed to the thoracoabdominal wall, contraction pulls the Under normal physiological conditions, the two pleural contents of the thorax inferiorly and pushes the abdominal layers are held together by the pleural fl uid and expand and contents inferiorly. Contraction of the diaphragm also assists contract as a unit. The space between the pleura is a “potential” the intercostal muscles to elevate the lower ribs. space because, under normal conditions, it does not exist. The second major muscle group involved in inspiration is However, excessive fl uid can build up between these spaces the intercostal group. The intercostal muscles are muscles that attach the ribs to each other. There are external and internal intercostals; the internal intercostals are further divided into interchondral (between ligaments) and intercostal (between bones) divisions. At rest, the ribs—attached anteriorly to the sternum and posteriorly to the thoracic vertebrae—tend to sag inferiorly and medially (Figure 20-11a). When the external intercostal muscles and the interchondral part of the internal intercostal muscles contract, they elevate the ribs in a motion similar to that of a bucket handle (Figure 20-11b). Functionally, when this happens in the rib cage, the volume of the rib cage increases. The chest wall interacts with the lung parenchyma via the pleura (Figure 20-12). The easiest way to visualize the pleura is to think about standing a bottle up on a fl at garbage Inhalation Figure 20-11 a-b Rib movement. (a) Full Scalene muscles exhalation position. (b) Full inhalation. elevate 1st and 2nd ribs Inferior part Visceral of sternum pleura moves anteriorly External intercostal Parietal muscles elevate ribs pleura Diaphragm moves inferiorly during contraction Figure 20-12 Pleural layers against the organs Figure 20-10 Muscles of respiration. (visceral pleura) and chest wall (parietal pleura). 362 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. during various disease states (e.g., heart failure) and air can of the conducting airways. Gas exchange does not occur in potentially enter the space (e.g., during chest trauma). When the conducting airways, hence the term “dead space.” The the pleural layers separate, they no longer function as a unit. anatomic dead space is typically 150 mL in the average adult This disrupts the pleural layers’ ability to generate an adequate male. There is also a physiologic dead space, which is the negative pressure during inspiration, thus reducing lung volume of the lungs not eliminating carbon dioxide; in certain volumes and creating a sensation of diffi culty breathing. disease states (e.g., pneumonia, congestive heart failure (CHF), pulmonary embolus, chronic obstructive pulmonary Respiratory Physiology disease (COPD), atelectasis, etc.) this volume may be greater than the anatomic dead space.8 Understanding the anatomy of the airway and respiratory Capacities are another way of describing the lungs’ system only tells half of the story. Knowledge of the respiratory volumes. Total lung capacity is the sum of the residual physiology, or the function, of the respiratory system allows volume, the expiratory reserve volume, the tidal volume, and the the Paramedic to understand the effects disease has on the inspiratory reserve volume. It is a measure of all of the airspace patient, the effects treatments have on the patient, and ways volume in the lungs with the potential to exchange carbon to troubleshoot the process when the patient does not respond dioxide. The total lung capacity can be broken down into smaller as expected. capacities. The vital capacity is a measure of the maximum volume that can move through the lungs in a single respiratory Lung Volumes and Capacities cycle and equals the inspiratory and expiratory reserve volumes Physiologically, the lung can be divided into several plus the tidal volume. The inspiratory capacity equals the tidal components. The measurements of lung volumes and capaci- volume plus the inspiratory reserve volume and is a measure ties (Figure 20-13) are important to facilitate descriptions of the maximum air that can be inspired. The air that remains of the physiologic occurrences during respiration. The total in the lungs at the end of expiration of the tidal volume is the lung volume is divided into a number of volume subsets. functional residual capacity and equals the expiratory reserve The fi rst, and most important, volume is the tidal volume. volume plus the residual volume.9 This is the volume of a normal breath and is approximately Minute ventilation measures the total volume of gas that 5 to 7 cc/kg of ideal body weight.7 During exercise or certain passes through the lungs in a minute. It equals the respiratory pathological situations, a greater volume—the inspiratory rate (RR) times the volume per breath (Tidal Volume, or reserve volume—is used. This is the maximum volume that TV). Normally, the volume per breath is the tidal volume. can be inspired above the tidal volume. The maximum volume Therefore, the standard formula for minute volume is RR that can be expired beyond the tidal volume is the expiratory TV9 (Figure 20-14). However, when other lung volume subsets reserve volume. Any air left in the lungs after the expiratory are used (e.g., inspiratory and expiratory reserve volumes) reserve volume is exhaled is the residual volume and cannot or the patient is breathing breaths that are smaller than tidal be exhaled; it refl ects the smallest possible airspace volume volume breaths, the volume per breath will change and thus based on the anatomy of the lungs. change the minute ventilation. Calculating minute ventilation Alveolar volume is the volume of air in the alveoli. In becomes important when determining the rate and volume at the average adult male, this volume is 350 cc and refl ects which a patient should be ventilated. the volume of air available for gas exchange. The fi nal Minute alveolar ventilation takes into account anatomic volume is the anatomic dead space, which is the volume dead space (Figure 20-14). It is calculated by subtracting (VC) (TLC) (IC) Inspiratory Reserve Volume (IRV) IRV Tidal Volume (VT) VT (FRC) Expiratory Reserve |
Volume ERV (ERV) Residual Volume RV (RV) Figure 20-13 Lung volumes. Airway Anatomy and Physiology 363 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Vital Capacity Total Lung Capacity Functional Inspiratory Residual Capacity Capacity RR × TV = Minute Ventilation the thorax. The parietal pleura is attached to the expanding structures and so increases in volume as well. Since the parietal and visceral pleura are functionally attached under BV − DS × RR = Minute Alveolar Ventilation normal conditions, the expanding parietal pleura pulls the Figure 20-14 Minute ventilation and minute visceral pleura along with it. Being attached to the exterior of alveolar ventilation. the lung parenchyma, the expanding visceral pleura expands the parenchyma and, through the network of connective tissue structures, pulls open the alveoli. The alveoli are connected to the external atmosphere via the lower and upper airways. Just as increasing the volume inside a syringe by pulling back the plunger creates a suction which pulls in air or medication, air is also pulled into the alveoli when their volume increases. Air fl ows from a higher pressure to a lower pressure and fi lls the vacuum in the expanding alveoli with air. In this way, inspiration of fresh respiratory gasses occurs. The volume of gas inspired from contraction of the diaphragm (primarily) and the intercostal muscles during resting ventilation is the tidal volume. As the lungs expand during inspiration, special sensory nerves called stretch receptors begin to fi re and, via the vagus nerve, inhibit further inspiration. This action is called the Hering-Breuer refl ex. Expiration during quiet breathing is the result of the passive recoil of the lung parenchyma and of Figure 20-15 Paramedic measuring peak fl ow in the chest wall. As these structures collapse, air simply fl ows a patient. out of the airspaces until the interthoracic pressure equals the atmospheric pressure. This is similar to what happens to an infl ated balloon when the neck is released; the elastic recoil of the balloon forces the air out into the environment. the dead space from the volume per breath and multiplying This elastic recoil is the expiratory component of the tidal the result times the respiratory rate ([Breath Volume – Dead volume and leaves the functional residual capacity in Space] RR). This calculation becomes important as various the lungs. devices such as endotracheal tubes, face masks, end-tidal High volume, active respiration (e.g., during illness, carbon dioxide detectors, or ventilator circuits are added. exercise, or other periods of high respiratory drive) uses These devices all increase the dead space. the accessory muscles of respiration. The accessory mus- While the capacities of the lungs and dead spaces are cles include the sternocleidomastoid muscle and scalenes important, equally important is the fl ow of gasses through (Figure 20-16). The sternocleidomastoid muscle elevates the structures. One of the most important fl ows is the peak the sternum and the scalenes elevate and hold in place the expiratory fl ow, or maximum velocity of gas movement upper ribs.11 Furthermore, the action of the intercostal during exhalation (Figure 20-15 and Skill 20-1). Many diseases restrict the fl ow of gasses during exhalation. Peak fl ow measurement can be used in the prehospital environment in to assess an asthmatic patient’s response to treatment.10 Scalene Sternocleidomastoid For a step-by-step demonstration of Peak Flow Trapezius Measurement, please refer to Skill 20-1 on page 371. Pectorialis The Bony and Muscular Thoracic Internal major inter- Structures and the Pleura costals Normal respiration occurs through a process of negative pressure, or vacuum, ventilation. Air moves into the lungs by the creation of a vacuum at the level of the alveoli. The structures Abdom- responsible for this vacuum are the bony and muscular structures inal of the chest wall, the diaphragm, and the pleura. muscles At the end of expiration, the air pressure in the alveoli is essentially atmospheric pressure. When the principal muscles Figure 20-16 Accessory muscles of inspiration of inspiration contract, they increase the external volume of and expiration. 364 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. muscles becomes more pronounced, resulting in “intercostal retractions” in which the musculature pulls in and the ribs become more pronounced and visible. Although the use of accessory muscles is effective in increasing minute ventilation by increasing the volume of the thorax, involving the accessory muscles in respiration is very tiring. Patients with minimal reserve energy may rapidly decompensate. Just as there are situations in which inspiratory reserve volume must be recruited, so too are there times in which active expiration must occur. During exercise or when expiratory airfl ow is obstructed (e.g., asthma, COPD exacerbation), the muscles of expiration may be recruited to increase the expiratory airfl ow above what can be accomplished through passive expiration. The muscles Intrathoracic pressure of expiration can be divided into two groups: the thoracic Preload muscles of expiration and the abdominal muscles of expiration (Figure 20-16). The thoracic expiratory muscles Cardiac output are the intercostal parts of the internal intercostals. When the intercostal parts of the internal intercostals contract, Figure 20-17 Effects of normal and positive they pull the ribs down and together, causing the rib cage to pressure ventilation on the circulatory system. collapse. This decreases thoracic volume and forces air out of the lungs.11 The abdominal muscles are also important for active expiration. The rectus abdominis, external obliques, internal Neurological Control of Breathing obliques, and transversus abdominus muscles perform Although the process of breathing is essentially involuntary, two major expiratory functions. First, they depress and there is a voluntary component as well. Differentiating anchor the lower ribs, which assist the thoracic expiratory between the two components assists the Paramedic in muscles to collapse the rib cage. Second, they compress the recognizing abnormal ventilation and considering possible abdominal contents and lower the intraabdominal volume. causes. This contraction causes the abdominal contents to push up on Sensory information comes from stretch receptors in the the diaphragm, further lowering the intrathoracic volume.11 lungs, the partial pressure of carbon dioxide in the bloodstream, Although the muscles of expiration are used much less the partial pressure of oxygen in the bloodstream, muscle frequently than the muscles of inspiration, they are effective spindle fi bers, and proprioceptors (position sensors) and in improving expiratory airfl ow. stretch sensors in the tendons and joints. Of these, increasing It is important to recognize that there are cardiac carbon dioxide is the greatest stimulus for ventilation in most implications of negative pressure ventilation. When the patients. All of the signals are processed in the brainstem and intrathoracic pressure decreases, the pressure in the vena modifi ed by the cortex. Primitive, involuntary control occurs cava and right atrium decreases, increasing venous return. in the medullary respiratory center of the medulla oblongata Therefore, during normal inspiration, venous return—and (the brainstem) with major nerve input from the vagus nerve. therefore preload—increases. When a patient receives There is an inspiratory center and an expiratory center of positive pressure ventilation, either during intubation or the medulla oblongata. The inspiratory center is responsible bag-valve-mask ventilation, intrathoracic pressure remains for inspiration and regular, rhythmic ventilation. There are positive during the entire respiratory cycle (Figure 20-17). As a number of nerve inputs; output from this group is via the a result, venous return—and therefore preload—decreases, phrenic nerve (from the 3rd, 4th, and 5th cervical nerve roots) resulting in a loss of cardiac output and blood pressure. to the diaphragm.9 Air trapping and hyperventilation also cause an increase in The expiratory center (the ventral respiratory group) is intrathoracic pressure, producing a potential drop in blood not normally active. It is responsible only for active expiration pressure in patients with borderline or poor cardiac function. and therefore stimulates abdominal wall musculature and the Additionally, the positive pressure in the lungs can increase intercostal parts of the internal intercostals. pulmonary vascular resistance and right ventricular afterload, Several chemicals act as stimuli for respiration. Carotid further exacerbating right heart failure. It is important to sinus and aortic arch chemoreceptors monitor carbon dioxide consider the hemodynamic effects of positive pressure levels in the blood. Additionally, chemoreceptors monitor ventilation when ventilating a patient. In general, patients the cerebrospinal fl uid for carbon dioxide, oxygen, and pH should be ventilated at a slower rate and with a slightly levels. Although carbon dioxide is the major determinant smaller volume than physiologic respiration to avoid the of respiratory drive, hypoxia is also a powerful stimulus to hemodynamic effects of overventilation. breathe. For some individuals with diseases that chronically Airway Anatomy and Physiology 365 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. increase the carbon dioxide levels (e.g., COPD), hypoxia may apnea without a sensation of needing to breathe. In addition, be the predominant stimulus. The chemoreceptors exert their strong emotions, fever, and pain will increase respiratory effects through the medulla. rate. The body’s response to metabolic acidosis is to increase There are two other important involuntary respiratory the respiratory rate and lower the carbon dioxide level (such centers, both located in the pons. The fi rst is the apneustic center as Kussmaul’s respirations in diabetic ketoacidosis). that serves as a backup stimulus for inspiration. The second is Pregnancy increases minute ventilation. Some medi- the pneumotaxic center, which inhibits inspiration. This center cations and drugs of abuse increase respiratory rate while serves to control respiratory rate and inspiratory volume.9 others (e.g., opioids) will decrease respiratory rate. Sleep Finally, as previously mentioned, there are other also decreases the respiratory rate. For the vast majority important contributions to respiration, particularly from the of breathing, involuntary control by the medullary centers cerebral cortex. There is some degree of voluntary control predominates (Figure 20-18). over ventilation. In times of stress, it is possible to suppress respiration to the point of syncope from hypoxia. However, Oxygen and Carbon Dioxide without the control of the cortex, the medullary centers resume control of breathing during unconsciousness. Additionally, Metabolism the cortex controls hyperventilation, an activity that can raise Respiration is the process of exchanging gasses, specifi cally the blood content of oxygen and lower the blood content oxygen and carbon dioxide, between an organism and its of carbon dioxide, allowing extended periods of conscious environment. The two major subtypes of respiration are Voluntary control Pain Emotions Temperature + = Stimulus increases rate + – and depth of breathing – = Stimulus decreases rate and depth of breathing Central Pons – chemoreceptor Respiratory center (↑CO2) + + + + Receptors in muscles – and joints + + + Irritant reflex Peripheral chemoreceptors (↓O2 ↑CO2 ↑H+ ↓pH) Hering-Breurer reflex External intercostal muscle Deflation reflex J-receptors Figure 20-18 Neurologic control of respiration. 366 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. external respiration, which is the exchange of gasses between 160 torr (Figure 20-19). Decreases in atmospheric pressure, the lungs and the red |
blood cells, and internal respiration, such as could occur during an air medical transport, will which is the exchange of gasses between the red blood cells decrease the partial pressures of a gas. Therefore, if the total and cells that make up the various body tissues. The airway, pressure were decreased to one half atmospheric pressure lungs, respiratory structures, and circulatory system exist to (380 torr), the partial pressure of oxygen would be one half assure adequate delivery of oxygen to the tissues and removal of what it was at sea level (21% 380 torr = 80 torr) even of carbon dioxide to the atmosphere. if the percentage of oxygen remained the same (21%). This The mechanisms described previously act to deliver decreases oxygen delivery to the bloodstream. If the patient oxygen to the alveoli and expel carbon dioxide out to the were placed on supplemental oxygen that increased the FiO 2 atmosphere. The amount of oxygen available at the alveoli, to 0.6 (60%) at sea level, the partial pressure of oxygen would called the partial pressure of oxygen, depends on the total increase to 456 torr, thus increasing the amount of oxygen atmospheric pressure and fraction of inspired oxygen, delivered to the bloodstream. Partial pressures, therefore, are abbreviated FiO . Room air, regardless of the atmospheric more important than percentages of the gas in determining 2 pressure, is made up of approximately 78% nitrogen, 21% how much oxygen will transfer from the alveoli to the oxygen, and 1% assorted other gasses. The concentrations of bloodstream and, ultimately, to the tissues. alveolar gasses, after dilution and humidifi cation, are 75% The pulmonary artery exits the right ventricle and nitrogen, 13% oxygen, 5% carbon dioxide, 6% water, and divides into smaller and smaller subdivisions. Eventually, less than 1% other gasses. The inspired FiO of room air is large capillary networks form over the surface of the alveoli. 2 21/100. Since FiO is typically expressed as a decimal, room Small amounts of interstitial fl uid and the very thin, highly 2 air FiO is 0.21. Placing a patient on a high fl ow oxygen permeable walls of the alveoli allow for rapid diffusion of 2 delivery device (e.g., a nonrebreather mask can increase the respiratory gasses from areas of high concentration to areas of percentage of inspired oxygen to between 80% and 100%. If a low concentration (Figure 20-20). In the case of carbon dioxide person breathes 100% oxygen, then the FiO is 100/100, or 1. (a waste product of metabolism), the highest concentration 2 A FiO of 1 is the highest FiO that can be delivered, because is in the pulmonary artery and the blood arriving at the 2 2 it means that all of the inspired air is composed of oxygen. capillaries. The inspired air (and therefore the air in the alveoli) The closer the FiO is to 1, the more oxygen is available at the has a much lower concentration of carbon dioxide. Therefore, 2 alveoli to diffuse into the blood. carbon dioxide diffuses from the bloodstream to the alveolar The concept of partial pressure is another factor in space. Conversely, oxygen is at its lowest concentration in determining the amount of oxygen available to the tissues. the blood arriving from the pulmonary artery (having been Normal atmospheric pressure at sea level is 760 torr (centi- used by the body during metabolism) and is at a much lower meters of water) and each gas in air makes up a percentage of that total amount, or total pressure. This is termed partial pressure (Figure 20-19) and is calculated by multiplying the air pressure by the fraction of that gas in the air. For example, to calculate the partial pressure of oxygen in room air at one atmosphere, multiply 0.21 (the FiO ) by 760 torr (atmospheric 2 Terminal brachiole pressure at sea level) to get a partial pressure of oxygen of CO O O 2 2 2 CO2 O2 O2 CO2 Room Air at Sea Level O2 CO2 O2 Alveoli atmospheric pressure : 760 torr O CO2 CO2 2 O O FiO2 21% : 0.21 2 2 Partial Pressure Oxygen 160 torr O2 O2 O2 O2 Room Air at Altitude CO2 atmospheric pressure : 380 torr O2 FiO2 21% : 0.21 CO2 CO2 Partial Pressure Oxygen 80 torr CO2 CO2 Capillary bed Supplemental Oxygen at Sea Level CO2 atmospheric pressure : 760 torr FiO2 60% : 0.60 Figure 20-20 Diffusion of oxygen and carbon Partial Pressure Oxygen 456 torr dioxide across the alveolar membrane occurs because of the concentration gradient across Figure 20-19 Partial pressure of gasses. the membrane. Airway Anatomy and Physiology 367 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. concentration than in the air in the alveoli. Therefore, oxygen Pediatric Anatomy will diffuse from the alveoli into the bloodstream. In this way, The most important differences between pediatric and the major respiratory gasses are exchanged. adult airway anatomy are those of size and proportions. If oxygen simply dissolved into the blood, only small One of the most challenging differences between adult amounts of oxygen could be carried at a time. Therefore, a and pediatric airway management is that pediatric patients more effi cient method of carrying oxygen is necessary. This are simply smaller. Smaller spaces, smaller patients, and a method uses hemoglobin, a large molecule in red blood cells requirement for more precision in action all combine to make that is intended to carry oxygen from the alveoli to the tissues the management of these patients potentially more diffi cult. (and, to a lesser degree, to carry carbon dioxide back to the The relative proportions of various structures are also alveoli). Approximately 97% of the oxygen carried in the important. These different proportions result in differences blood is bound to hemoglobin; the rest is dissolved directly in management and technique between adult and pediatric into the plasma. Usually all of the systemic arterial hemoglobin patients. However, these differences do not necessarily make is carrying oxygen and is therefore saturated with oxygen. pediatric airway management more diffi cult; it is simply Devices such as a pulse oximeter can measure the percentage different. For the experienced Paramedic, the pediatric airway of hemoglobin that is carrying oxygen. In healthy individuals, may be easier to manage than the adult airway; the key is oxygen saturation is typically 98% or greater. Arterial pressure the degree of familiarity with the structures, proportions, and of oxygen, PaO , is a measurement of the amount (pressure) 2 equipment. Therefore, an understanding of the anatomical and of oxygen in the blood. In a healthy adult breathing room air, proportional differences, as well as experience in pediatric the PaO will be between 80 and 100 cm water. 2 airway management, is critical in making the provider Carbon dioxide (CO ), produced by the tissues 2 comfortable with pediatric airway management. Table 20-1 during metabolism, is returned to the alveoli for disposal. summarizes the anatomical differences in pediatric patients. Approximately 33% of CO is attached to hemoglobin. The 2 The most obvious difference between pediatric and adult rest is either dissolved in the blood or combines with water to patients is size. However, it is probably the relative proportions form bicarbonate ions. These release the carbon dioxide when that are most important. A pediatric patient’s head, when they reach the alveoli. The arterial pressure of carbon dioxide compared to his body, is disproportionately larger than an (PaCO ) is the measure of carbon dioxide in the blood and is 2 adult’s head. This is due to the more protuberant pediatric normally 35 to 45 mmHg. occiput.12 Therefore, when a pediatric patient is in a supine Numerous disease states can affect the amounts of position, the protuberant occiput will tend to fl ex the neck oxygen and carbon dioxide in the blood. Lowered atmospheric and compress airway structures, resulting in turbulence and concentrations associated with partial pressures of oxygen increased resistance to airfl ow. As mentioned, the child’s airway and lowered hemoglobin concentrations both decrease the is smaller, so even a small degree of obstruction can signifi cantly total amount of oxygen in the blood. Decreased surface area affect the pediatric patient’s oxygenation and ventilation. for exchange such as occurs in trauma (e.g., hemothorax, Advancing into the oropharynx, a child’s tongue is pneumothorax, pulmonary contusion) and medical diseases disproportionately larger compared to the oral cavity than (e.g., COPD, pneumonia, effusions, atelectasis, CHF with an adult’s tongue. In addition, the tonsils and adenoids are pulmonary edema, etc.) will decrease the amount of oxygen disproportionately large and the mucosa over them and the reaching the tissues. Also, decreased mechanical effort—such entire pharynx is more friable, or fragile. When traumatized, as occurs with head injuries, strokes, overdoses, and pain— these structures tend to bleed. Therefore, precision in blade will decrease the available oxygen. Carbon dioxide levels are primarily controlled by ventilation. Therefore, PaCO will rise with hypoventilation and 2 fall with hyperventilation. Although some metabolic processes Table 20-1 Differences Between Pediatric can increase production of carbon dioxide, the lungs typically Airway Anatomy and Adult Airway Anatomy do an excellent job of compensating for these changes. • More pronounced occiput, fl exing head and neck when supine on a fl at surface Pediatrics • Proportionately smaller airway diameter • Proportionally larger tongue, tonsils, and adenoids Although there are signifi cant differences between adult and pediatric patients—which are refl ected in some changes in • More friable mucosa practice and equipment—the fundamental anatomy and • Floppier and posterior sloping epiglottis physiology are the same. The same structures exist in both • Larynx position more anterior and toward head the adult and the pediatric airway and the ultimate purpose— • Vocal cords pinker and angled toward feet exchange of respiratory gasses—remains the same. Therefore, • Airway smallest at level of cricoid cartilage with the previous discussion of adult anatomy and physiology • Trachea angled anterior and shorter in mind, this section will focus on the major differences • More susceptible to gastric distention between adult and pediatric patients. 368 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. placement, care in movement of the devices and equipment in pediatric patient should be ventilated with smaller pressures in the mouth, gentle pressure, and control of the tongue are all an effort to minimize gastric infl ation. Decompression of the critically important in the management of the pediatric airway. distended stomach will signifi cantly improve the respiratory Moving deeper into the hypopharynx, there is a much mechanics and should routinely be performed on any child more acute angle from the pharynx to the epiglottis. The who has received positive pressure ventilation. epiglottis is also “U” shaped and less rigid as the cartilage has not fully matured.13 This immaturity also causes the epiglottis Physiology to slope more posteriorly, potentially obscuring the view of Four major physiologic differences between adults and chil- the glottis. dren are of signifi cance to ventilation and airway management. At the level of the larynx, the fi rst recognizable difference The fi rst of these relates to the nature of respiratory distress, is the position. At birth, the tracheal opening lies at the level respiratory failure, and cardiovascular collapse in pediatric of the fi rst cervical vertebrae (C-1). By ages 5 to 7, relative patients. Multiple disease processes affect the basal metabolic differences in structural growth rates have moved the glottic rate and respiratory status of children. The common pathway opening to the C-3 to C-4 level, and by adulthood, |
the glottis to morbidity and mortality for many of these diseases is rests at the C-5 level.14 On laryngoscopic view, therefore, respiratory failure. Initially, pediatric patients are able to the glottis will be signifi cantly closer to the oropharynx and compensate for increasing respiratory demands. However, will be in a relatively more anterior position than would be their dependence on the diaphragm for almost all inspiratory expected in an adult. effort, their ability to recruit intercostal and accessory mus- Examining the laryngeal opening, a number of differ- cles, and the immaturity of the accessory musculature puts ences are noted. The arytenoids are disproportionately large pediatric patients at risk to tire rapidly. Therefore, these and are thus more prominent. The vocal cords are pinker and patients decompensate quickly. By the time a pediatric more diffi cult to differentiate from the surrounding tissue. In patient goes into respiratory failure, most of his metabolic addition, the cords are angled toward the feet anteriorly and and oxygen reserves are depleted.15 Secondary cardiovascular toward the top of the head posteriorly, sloping upward from the collapse, which is often irreversible, is likely to occur. This front of the child toward the back. This is different from adult ability to initially compensate and then rapidly and irreversibly vocal cords that tend to be on the same plane from front to decompensate is a hallmark of pediatric respiratory failure. back and creates the perception that the space is signifi cantly Table 20-2 summarizes the differences between pediatric smaller. These anatomic differences can be striking the fi rst respiratory physiology and adult respiratory physiology. time a Paramedic visualizes the pediatric larynx. At the level of the thyroid cartilage, another important difference is noted. The cricothyroid membrane is propor- tionately smaller in children and is almost nonexistent in Street Smart infants. Up to age 10, it is diffi cult to identify the cricothyroid membrane by palpation. The cricoid ring is also different in By the time a pediatric patient is in respiratory failure the pediatric patient. In the adult airway, the vocal cords are the and cardiovascular collapse, it may be very diffi cult narrowest point in the upper airway. For the pediatric patient, the cricoid ring has the smallest cross-sectional area. This to reverse the process. Early recognition of subtle makes the larynx and trachea funnel-shaped. An endotracheal signs (e.g., agitation, grunting, tripod positioning, tube that is introduced into the airway, therefore, may pass retractions, etc.) of respiratory distress and rapid the vocal cords without a problem but may have diffi culty intervention are necessary to prevent respiratory passing the cricoid ring. Aspirated foreign bodies may also lodge at this point. failure and the ensuing cardiovascular collapse. There are also signifi cant differences in the trachea itself. Compared to the adult trachea, the pediatric trachea is angled much more anteriorly as it travels inferiorly. In addition, the Table 20-2 Differences Between Pediatric trachea is proportionately shorter and there is signifi cantly Respiratory Physiology and Adult Respiratory Physiology less distance between the vocal cords and the carina. Minimal head movement in the pediatric patient can result in signifi cant • Respiratory failure is primary cause of death in pediatric patients displacement of the tip of an endotracheal tube. compared to cardiovascular failure in adults. One other important anatomic difference related to • Pediatric patients decompensate rapidly. management of the pediatric airway actually relates to the • Pediatric patients have proportionately higher oxygen consumption pediatric gastrointestinal tract. Pediatric patients are much than adults. more susceptible to gastric distention during positive pressure • Pediatric patients have a smaller residual capacity than adults. ventilation. Pediatric patients are less able to tolerate gastric • Increased vagal tone in pediatric patients causes bradycardia. distention due to their smaller lung volumes and their • Hypoxia in pediatric patients causes bradycardia. dependence on the diaphragm for respiration. Therefore, the Airway Anatomy and Physiology 369 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. A second important metabolic difference between in a similar clinical context and more likely to suffer early children and adults relates to oxygen consumption. For their hypoxic injuries. size, pediatric patients consume more oxygen. Their basal Finally, pediatric patients have the potential for high vagal metabolic rate is, by body surface area, signifi cantly higher tone. Minimal airway stimulation can result in excessively high than an adult’s and basal oxygen consumption per square vagal response including bradycardia and asystolic cardiac meter can be twice as high as that of an adult.16 Therefore, arrest. This includes stimulation from a laryngoscope blade. they become hypoxic rapidly during respiratory failure. Pediatric patients tend to have copious secretions, increasing The third difference is that, for their size, pediatric the risk for aspiration and diffi culty maintaining an airway. patients have a disproportionately smaller functional residual Therefore, administration of appropriate vagolytic medications capacity. Thus, in times of respiratory distress, children are (e.g., atropine) before airway management is critical. less able to draw upon this capacity to provide supplemental It is important to note, however, that pediatric patients ventilation. Furthermore, in times of apnea, the pediatric will also become bradycardic when hypoxic. Therefore, patient will become hypoxic up to twice as quickly as an rapid differentiation between hypoxia and excessive vagal adult.17 Therefore, pediatric patients are more likely to tone is critical when a pediatric patient in respiratory distress progress to respiratory failure faster than an adult would becomes bradycardic. 370 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Skill 20-1 Peak Flow Measurement 1 Position patient seated upright. 2 Reset indicator. 3 Instruct patient to inhale as deeply as 4 Instruct patient to tightly wrap mouth possible. around mouthpiece. 5 Instruct patient to exhale as fast as 6 Read indicator. possible. Airway Anatomy and Physiology 371 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. The fi rst step Paramedics require to achieve effi cient, safe, and effective airway and ventilation management in their patients is to be familiar with normal airway anatomy and respiratory physiology. By being knowledgeable about these topics, the effective Paramedic can recognize abnormal fi ndings and troubleshoot failures in the management of an airway or ventilation. Key Points: • The airway is divided into upper and lower regions. • The head-tilt chin-lift or jaw thrust maneuvers The upper airway begins at the nares and mouth open an airway by fi rst lifting up the hyoid bone via and extends to the glottis. The lower airway anterior mandibular displacement. extends from the glottis to the alveoli. • The larynx is made up of a number of cartilaginous • The mouth and nose both defi ne the beginning of structures including the thyroid cartilage and the airway. The nose serves as an immunological the aryepiglottic folds that contain the arytenoid barrier, a source of warming and humidifying air, cartilages. and a threat/food detection system. • The “Adam’s apple,” formed by thyroid cartilage, • The pharynx is the area of the airway composed of is the large, anterior shield-like cartilage that the spaces behind the nose (nasopharynx) and the forms the majority of the anterior portion of the oral cavity (the oropharynx). larynx. • The oral cavity is bound by the lips anteriorly, the • The open space superior to the vocal cords is the buccal surfaces laterally, the tongue inferiorly, vestibule. Folds in the vestibular membrane form the hard palate superiorly, and the soft palate the false cords that can seal over the glottis to posteriorly. help protect the airway from aspiration of foreign • Food and respiratory gasses move through the oral materials. cavity and tonsillar pillars that form the walls of • The vocal cords are composed of mucosal folds the oral pharynx. These structures serve as an overlying ligaments, cartilages, and muscles. As immunological barrier to pathogen entry in the a part of the cricothyroid ligament, the vocal pharynx. ligaments form the true vocal cords that are visible • When performing airway management procedures at the bottom of the vestibule. the Paramedic should be aware of the high risk of bleeding due to vascularized mucous membranes • Vocal cords are responsible for the production as well as the risk of swelling or occlusion caused of speech and sound as well as protection of the by oral infections. airway. • The epiglottis protects the lower airway from • A number of stimuli can trigger an involuntary foreign body aspiration. refl ex that causes the muscles to adduct the glottis and the false cords to provide an impenetrable • Airway obstruction in the obtunded patient is not barrier to foreign material. caused from the tongue falling posteriorly, but rather initially by the soft palate and the epiglottis • The cricoid ring, the only complete ring in the making contact with the posterior wall of the trachea, is located at the lowest portion of the oropharynx and pharynx. larynx and the beginning of the trachea. 372 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. • The intrinsic and extrinsic laryngeal muscles • Exhalation is normally passive; however, active and their nerve supply found in the larynx are muscles of expiration are utilized during periods of responsible for the “gag refl ex.” inadequate exhalation. • The thyroid gland is a highly vascular, “H” shaped • Quiet breathing or normal inspiration is a function structure that lies along the side of the larynx and of principal muscles and passive exhalation. During upper trachea. active breathing, such as heavy activity, accessory • The common carotid artery and the internal jugular muscles may be used for inspiration and active veins are two sets of major vascular structures that muscles used for expiration. run parallel to the pharynx. • The diaphragm is a large, thin, muscle that divides • The trachea is the portion of the airway from the the abdomen for the thorax. cricoid ring to the carina. • The intercostal muscles attach the ribs to each • At the level of the carina, the lower airway splits other and are the major muscle group involved in into the two mainstem bronchi, the right and left. inspiration. The right mainstem bronchus divides into three lobar bronchi and the left mainstem bronchus • The chest wall is lined with the parietal pleura separates into two lobar bronchi. The right that lies against the outer lining of the lungs, the bronchus is more acutely angled and predisposes visceral pleura. A small amount of fl uid between the endotracheal tubes, suction catheters, and foreign two layers allows them to slide against each other bodies to enter more often than the left bronchus. but not pull apart. • As the bronchi decrease in diameter they become • During inspiration, principal muscles increase the bronchioles. The muscles in the bronchi and external volume of the thorax. The parietal pleura bronchioles are capable of |
closing off the airway is attached to the expanding structures and, under when bronchial spasms occur. normal conditions, pulls the visceral pleura along • with it. The expanding visceral pleura expands the The end of the terminal bronchioles have the lung tissue, pulling open the alveoli. alveolar ducts that open into the alveolar air sacs where gas exchange occurs. • As the volume inside the alveoli increases, a lower • The fl uid surfactant that holds the alveoli open pressure is created inside the alveoli. by decreasing the surface tension of the alveoli • Lung expansion is controlled by stretch receptors prevents atelectasis (collapse of the alveoli). that inhibit further inspiration. Expiration is the • Determinations of lung volumes and capacities are passive recoil of the lungs and chest wall that forces important to facilitate descriptions of the physiologic air out until interthoracic pressure equals that occurrences during respiration. The most important atmospheric pressure. measurement to the Paramedic is the volume of air • Accessory muscles are used during high volume moved at normal breath or tidal volume. active respiration. Accessory muscles include the • Tidal volume multiplied by the respiratory rate is sternocleidomastoid muscles, the scalenes, and the equal to the minute ventilation which is important intercostal muscles. in determining at what rate of volume a patient • Thoracic expiratory muscles and abdominal muscles should be ventilated. may be used to decrease the thoracic volume and • The peak fl ow, or maximum velocity of gas force air out of the lungs in times of exercise or movement, can be used to assess a patient’s when expired airfl ow is obstructed. breathing, particularly in the assessment of asthmatic patients. • During normal inspiration the decrease in • intrathoracic pressure causes an increase in venous Normal respiration occurs through a process of blood return or preload. When a patient receives negative pressure ventilation. positive pressure ventilations preload may decrease • The muscles for inspiration can be divided into the due to intrathoracic pressure remaining relatively principal and accessory muscles. the same. Airway Anatomy and Physiology 373 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. • Increasing carbon dioxide is the greatest stimulus for • Some oxygen and a large percentage of carbon ventilation in most patients, but sensory information dioxide are dissolved directly in the blood. comes from stretch receptors in the lungs. • Diseases that decrease the surface area for gas • Involuntary control of respirations occurs in the exchange can decrease the amount of oxygen in respiratory center of the medulla oblongata. the blood, which decreases the amount of available Sensory information is received from the vagus oxygen reaching the tissues. nerve and stimuli are sent out via the phrenic • Carbon dioxide levels are primarily controlled by nerve. The inspiratory center of the medulla is ventilation in response to changes in PaCO2. The responsible for inspiration and regular, rhythmic lungs can compensate for changes in CO2 through ventilation. The expiratory center is responsible increasing or decreasing ventilatory rates. only for active expiration when needed. • Differences between pediatric and adult airway • Chemoreceptors monitor carbon dioxide levels anatomy are those of size and proportions: in the blood and spinal fl uid. For patients with ■ A pediatric patient’s head, when compared to his diseases that chronically increase carbon dioxide body, is disproportionately larger than an adult’s. levels, hypoxia (oxygen defi ciency) may also be the ■ In the oropharynx, a child’s tongue is predominant stimuli to breath. disproportionately larger than an adult’s when • compared to the oral cavity. Located in the pons, the apneustic center serves as ■ The structures of the oral cavity are also more a backup stimulus for involuntary respiration and the fragile in pediatric patients than in adults. pneumotaxic center inhibits inspiration. Although it ■ In the hypopharynx of the pediatric patient, the is possible to suppress respirations, once the patient epiglottis may obscure the view of the glottis is unconscious medullary centers resume control. due to the shape and acute angle of the pharynx. • The two major subtypes of respiration are external ■ The tracheal opening is relatively more anterior respiration, which is the exchange of gasses and signifi cantly closer to the oropharynx. between the lungs and the red blood cells, and ■ Large arytenoids and pinker vocal cords that are internal respiration, which is the exchange of gasses set on an angle are further differences. between the red blood cells and cells that make up ■ The narrowest point in the pediatric airway is the various body tissues. not the vocal cords as found in adults, but the • cricoid ring. Room air is made up of approximately 78% nitrogen, ■ The pediatric airway is proportionally shorter 21% oxygen, and 1% assorted other gasses. The FiO2 and more anterior than the adult’s. of room air is expressed as a decimal, 0.21. ■ Pediatric patients have smaller lung volumes • Partial pressure of gasses is a factor in determining than adults. how much oxygen will transfer from the alveoli to ■ Pediatric patients depend on the diaphragm for the bloodstream and, ultimately, to the tissues. respiration. • Diffusion of respiratory gasses from a high • Pediatric patients are able to compensate for concentration to a low concentration occurs across increased respiratory demands but are at risk to tire the highly permeable wall of the alveoli. rapidly and decompensate quickly. • Diffusing from high to low concentrations, carbon • For their size, pediatric patients consume more dioxide diffuses out of the blood as oxygen diffuses oxygen than adults and may rapidly become hypoxic from the alveoli to the bloodstream. during respiratory failure. • Hemoglobin is a large molecule found in red blood • Consider hypoxia as the cause of bradycardia in a cells that carries approximately 97% of oxygen from pediatric patient. the alveoli to tissues. In addition, 33% of carbon • Airway stimulation may also result in bradycardia dioxide is attached to hemoglobin as the blood due to the potential for high vagal tone found in returns from the tissues to the alveoli for disposal. pediatric patients. 374 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Review Questions: 1. Describe the route an oxygen molecule takes 10. List the airway structures of the lower airway. from the oral or nasal cavities to the alveolar 11. Diagram the alveolar unit including the capillaries. pulmonary capillaries. 2. List three functions of the nares. 12. List the cell types found in the walls of the lower 3. Describe the anatomic “contents” of the airway structures. oropharynx. 13. Describe the bony and muscular structures of 4. Diagram the anatomy of the epiglottis, glottis, the chest wall. vocal cords, and esophagus as viewed with a 14. Name the structure most responsible for the laryngoscope. nervous system’s control of ventilation. 5. Describe the relationship of the hyoid bone to 15. Describe the two-layer nature of the pleura. the tongue and epiglottis. 16. List two stimuli for breathing and identify which 6. Name the most common cause of airway provides respiratory drive in most individuals. obstruction. 17. Describe how positive pressure ventilation 7. Differentiate between the “upper” and “lower” changes the normal intrathoracic pressure. airway. 18. List key anatomic differences in the pediatric 8. Diagram the relationship between the thyroid upper airway versus the adult upper airway. cartilage, the cricoid cartilage, the vocal cords, 19. List key anatomic differences in the pediatric and their associated structures. lower airway versus the adult lower airway. 9. List the differences between the cricoid ring 20. List differences in pediatric and adult and lower tracheal rings. respiratory physiology. Case Study Questions: Please refer to the Case Study at the beginning of the 3. How can changing the percentage of oxygen, or chapter and answer the questions below: FiO 2, and the partial pressure of oxygen increase 1. What structures are kept open by continuous the overall exchange of respiratory gasses? positive airway pressure (CPAP?) 4. Describe “work of breathing.” 2. Which of these structures exchange gasses? Airway Anatomy and Physiology 375 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. References: 1. Boerner TF, Ramanathan S. Functional anatomy of the airway. In: 10. Richmond NJ, Silverman R, Kusick M, Matallana L, Winokur J. Out Benumof JL, ed. Airway Management: Principles and Practice. of hospital administration of albuterol for asthma by basic life support St. Louis: Mosby; 1996. providers. Academic Emergency Medicine. 2005;12(5):396–403. 2. Williams P, Warwick R, Dyson M, et al. Gray’s anatomy (37th 11. Netter FH. Atlas of Human Anatomy. Summit: Ciga-Geigy; ed.). New York: Churchill Livingston; 1989:1248–1286. 1989:183. 3. Shorten GD, Opie NJ, Graziotti P, et al. Assessment of upper 12. Luten RC. The pediatric patient. In: Walls RM, ed. Manual of airway anatomy in awake, sedated, and anesthetized patients Emergency Airway Management. Philadelphia: Williams and using magnetic resonance imaging. Anesths Intensive Care. Wilkins; 2000:144. 1994;22:165. 13. Berens R, Day S. Airway management. In: Jaimovich D, 4. Netter FH. Atlas of Human Anatomy. Summit: Ciga-Geigy; Vidyasagar D, ed. Handbook of Pediatric and Neonatal Transport 1989:23–75. Medicine (2nd ed.). Philadelphia: Hanley and Belfus; 2002:174. 5. Netter FH. Atlas of Human Anatomy. Summit: Ciga-Geigy; 14. Luten RC. The pediatric patient. In: Walls RM, ed. Manual of 1989:167–199. Emergency Airway Management. Philadelphia: Williams and 6. Netter FH. Atlas of Human Anatomy. Summit: Ciga-Geigy; Wilkins; 2000:143. 1989:170–171. 15. Strange GR. (Ed.). APLS: The Pediatric Emergency Medicine 7. Guyton AC, Hall JE. Textbook of Medical Physiology (9th ed.). Course. (3rd ed.). Dallas: ACEP; 2000:3–15. Philadelphia: W.B. Saunders; 1996:481–485. 16. Markenson DS. Pediatric Prehospital Care. Upper Saddle River: 8. Costanzo LS. Physiology. Philadelphia: Williams and Wilkins; Prentice Hall; 2002:98. 1995:107. 17. Luten RC. The pediatric patient. In: Walls RM, ed. Manual of 9. Costanzo LS. Physiology. Philadelphia: Williams and Wilkins; Emergency Airway Management. Philadelphia: Williams and 1995:108–124. Wilkins; 2000:143. 376 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Public Health and the Paramedic 377 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. KEY CONCEPTS: Upon completion of this chapter, it is expected that the reader will understand these following concepts: • Algorithms that provide a specifi c planned set of actions and decisions where the if-then decisions are made in advance • Ways the Paramedic utilizes an algorithmic approach to airway management • The fi ve criteria that determine how aggressive an approach to airway and respiratory management is needed • Disease processes encountered in the prehospital environment that can |
cause a patient, the patient’s airway, or the patient’s respiratory status to deteriorate • An algorithmic approach to patients who initially cannot be ventilated • Airway management after a failed intubation attempt Case Study: The Paramedics were called to the intersection of Old State and Fish House Roads for a two-car MVC with signifi cant injuries. The driver of a pickup truck was out of the vehicle and on the ground 378 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. with the fi rst responding EMTs working to ventilate him. The man had serious facial trauma and the EMTs were unable to adequately ventilate him, as evidenced by poor chest rise. They asked the Paramedic what he planned to do. The Algorithmic Approach to Airway Management 379 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. OVERVIEW As part of the ABCs of primary assessment, airway management is a critical component in treating life-threatening conditions. As opposed to protocols that detail treatments for a specifi c working diagnosis, an algorithm provides the Paramedic with a specifi c planned set of actions and decisions where the if this––then that decisions are made in advance. The Paramedic can utilize an algorithmic approach to airway management based on criteria that determine a patient’s need for airway and respiratory interventions. The Paramedic uses the airway management algorithm and knowledge of the many different disease processes that patients can present in the prehospital setting to identify and manage a patient’s airway and respiratory status. When the Paramedic is presented with a patient who initially cannot be ventilated or whose airway is unable to be secured, the airway management algorithm offers a preplanned approach to ensure that the best patient care possible is provided. Airway Management be accomplished for a given patient for a specifi c presumptive diagnosis. For example, a chest pain protocol may dictate that Airway management is one of the most critical tasks a all patients with chest pain of possible cardiac origin must Paramedic performs. The consequences of an unmanaged or receive vital signs assessment, oxygen, aspirin, nitroglycerin, poorly managed airway are devastating and potentially fatal. morphine, an IV, and cardiac monitoring. For a Paramedic, however, the feeling of accomplishment that Although there may be some specifi c order details within comes with properly managing the impossible airway can the protocol (e.g., “The fi rst nitroglycerin may be given before be its own reward. By defi nition, any emergency airway is an IV is established if the systolic blood pressure is greater considered diffi cult. Regardless of the patient’s anatomy, the than 120”), the actual order in which they are carried out is circumstances and urgency of managing the airway make it usually not critical to patient outcomes. It is expected that the more diffi cult than in a non-emergency, in-hospital situation.1–4 Paramedic will perform all of the care specifi ed in the protocol. Preplanning becomes critical to prevent inaction, wrong action, In certain emergency situations (e.g., cardiac arrest with and panic. ventricular fi brillation), specifi c tasks must be carried out the In patient care, the most common form of preplanning is same way, in the same order, in a very limited time period. the algorithm. This chapter examines the utility of algorithms Furthermore, the care must be modifi ed based on the patient’s and introduces the reader to three algorithms that can be response to the interventions. In these cases, algorithms are utilized for the management of any prehospital emergency applied. In essence, these are care guides based on “if-then” airway. Chapters 22 and 23 will examine each technique branch points. That is, a specifi c intervention is applied (e.g., listed in the algorithms in depth. It is important to note that defi brillation). If an event occurs (e.g., conversion to sinus even if a Paramedic does not adopt a formal algorithm, the rhythm) then another action is performed (e.g., administer basic principle of preplanning remains the same. It is also an anti-arrhythmic medication). However, if a different event important to emphasize that algorithms do not replace the occurs (e.g., the patient remains in ventricular fi brillation), Paramedic’s critical thinking skills. By knowing what to do then a different action is performed (e.g., start CPR, intubate, next if what is being done now doesn’t work, the Paramedic insert an IV, and give epinephrine) (Figure 21-1). can successfully negotiate any airway. The algorithm typically does not give wide latitude in decision making. By using a specifi c planned set of actions Algorithms and decisions, the Paramedic, at the time of the emergency need only to perform the algorithm and monitor patient In every patient encounter, the Paramedic applies a group responses to ensure the best patient care is provided. of patient care activities based on a presumptive conclusion One of the greatest advantages of algorithms is that the called a working diagnosis. These activities have been if-then decisions are made in advance. Instead of having previously planned and documented, usually in the form of the Paramedic consider the advantages and disadvantages a protocol. of a particular intervention while managing a critically ill Protocols are the fundamental guides to prehospital care. patient, other individuals—in calmer and less pressured A protocol details a specifi c group of activities that are all to circumstances—have already considered the literature 380 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Defibrillation may be unable to make a good decision to try an alternative approach. Considering the use of an algorithm in every airway management event is completely appropriate. The algorithm, however, is just one of many tools used in airway and respiratory management. Appropriate equipment, education, Yes Conversion No to sinus practice, and a thorough knowledge base are also critically rhythm? important tools. Therefore, the algorithm should be used in the context of excellent airway management skills and Administer Start CPR knowledge. It is the Paramedic’s responsibility to maximize antiarrhythmic the quality of care. therapy Development of Algorithms Figure 21-1 Example of an algorithm. Currently, algorithms are the tools of choice for dictating care in critically unstable prehospital patients. Classes in which a Paramedic will be most familiar that rely on algorithms and anecdotal experience and have formed a consensus include Advanced Cardiac Life Support and Pediatric decision on treatment. Algorithms are developed in a low- Advanced Life Support. In the airway management arena, stress environment where options can be discussed and fully the American Society of Anesthesiologists’ “Diffi cult Airway evaluated as opposed to those decisions made at the patient’s Algorithm,” the Advanced Trauma Life Support Trauma side, under high-stress and high-pressure circumstances. Airway Algorithm, and the National Emergency Airway In addition, algorithms provide an impetus for continuing Management Course Algorithm all represent various authors’ action. In an emergency situation, the risk exists that a and committees’ approaches to addressing specifi c airway Paramedic can become so focused on a single task that, even management issues. Of these, the ASA’s “Diffi cult Airway in the face of failure of that task, the Paramedic repeatedly Algorithm” has the most support in the literature.5,6 continues to perform that task. Use of an algorithm can The ASA’s “Diffi cult Airway Algorithm” resulted from prevent this from occurring. the fi ndings of a closed claims analysis of closed legal For example, some scene management algorithms for actions against anesthesiologists. The analysis found that critically ill trauma patients do not allow any attempts to three mechanisms (inadequate ventilation—38%, esophageal initiate IV access on-scene before the patient is loaded and intubation—18%, and diffi cult airways—17%) accounted for transported. These algorithms come from evidence that almost three-quarters of all adverse outcomes. The Diffi cult providers can become so fi xated on inserting an IV that multiple Airway Algorithm was subsequently developed to address at attempts result in signifi cant delays on-scene. By mandating least one of these three mechanisms. that sequential tasks occur and that care “moves” and is not In developing a systematic way to reduce the bad “stalled” on a single task, algorithms promote good care. outcomes associated with diffi cult airways, the ASA Task There are some important considerations in the use Force on Management of the Diffi cult Airway looked to the of an algorithm. Although the decisions about “what to do literature for a valid methodology for guiding patient care next” have already been made, they have not been made activities in the setting of potentially critical illness. Two by the individual facing a particular airway at a particular fi ndings guided them in developing an algorithm. The fi rst time. Therefore, even the best algorithm can only serve as was the fi nding that certain specifi c management techniques a guide; it is never a rigid absolute set of rules that must be had been clearly demonstrated to improve patient outcomes. mechanically followed. Deciding not to follow an algorithm, The second fi nding was that, although there was no airway or however, is not a decision to be made lightly. anesthesia literature to demonstrate that linking the individual The Paramedic should understand and routinely apply strategies to algorithms was benefi cial, the cardiopulmonary an airway management algorithm to the point that it is done resuscitation literature clearly demonstrated that algorithms automatically. This degree of familiarity implies that, when were benefi cial in the management of life-threatening cardiac a radically different situation is encountered, the Paramedic events. Based on these two fi ndings and expert consensus, an can intelligently consider and reject the algorithm if it is algorithmic approach to airway management was adopted. inappropriate. For example, a patient with a traumatic transection of the trachea is neither an appropriate candidate for repeated oral Assessment of an Algorithm’s Impact intubation attempts nor, when they fail, for the placement of a The impact of airway management algorithms on patient blind insertion airway device. In fact, this patient is a candidate outcomes, however, has not been clearly demonstrated. for a technique not addressed in any airway algorithm: direct Assessing the impact of the ASA’s Diffi cult Airway Algorithm intubation of the trachea at the level of the transection. is confounded by a number of variables. However, without understanding standard algorithmic Although this algorithm is almost universally used in management and why it is inappropriate, the Paramedic the anesthesia setting, a repeat analysis of closed claims The Algorithmic Approach to Airway Management 381 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. in 2000 that looked exclusively at diffi cult intubations was dividing between intubating airway care (the ability to use an only able to fi nd 98 cases from prior to implementation of endotracheal tube or blind insertion airway device) and non- the algorithm. The second diffi culty in determining the intubating airway management is a reasonable approach and algorithm’s impact is the number of confounding factors. For |
the one taken in the following algorithms. example, the laryngeal mask airway was not commonly used before the algorithm was published; it is now very common Decision to Intubate and/or Provide in anesthesia practice and has been added to the algorithm. Respiratory Support Algorithm Changes in the number of non-physician anesthetists and The Paramedic’s most important task is to recognize a patient’s their practice patterns all confound any analysis. need for airway or respiratory support. Generally, this patient Finally, only historical control data is available to assessment is taught as part of the ABCs: Does the patient compare with new data; this increases the risk of unmeasured have a patent airway, is the patient breathing, and what is the confounding factors impacting the outcome. In short, even patient’s circulatory status? Parameters such as “respiratory with large numbers of patients and a strong monitoring system, rate < 10 or > 28” are used to guide interventions. However, using the largest database monitoring the impact of an airway using parameters fails to address the “why” aspect of airway algorithm may be inadequate to conclusively demonstrate that management. By understanding why a patient may need an algorithmic approach to emergency airway management is airway and respiratory support, the Paramedic is better able more effective than other approaches. to determine when and how to provide that support. This limitation is true, however, only in the context of Every patient requires some degree of airway management the ASA algorithm. Emergency airway algorithms have and respiratory support. The question that must be answered the advantage of starting with a single diagnosis: a patient is how much can the patient do on his own and how much in need of airway and ventilation management. Therefore, support does he need from the Paramedic. For example, a research into the effi cacy of airway management algorithms healthy 23-year-old woman with an ankle fracture can probably in the prehospital environment may be possible if two similar completely support her own airway and respiratory status. The EMS systems can be compared—one trained in and using same patient, however, after high dose morphine may require an algorithm and one not. Until such research is completed, active airway and respiratory support by the Paramedic. The however, the debate between pro-algorithm and pro-point of key is recognizing the difference between these two scenarios. care clinical decision making will continue. There are fi ve reasons why patients may require active airway or respiratory management (Table 21-1). By assessing Prehospital Airway each of these reasons in a systematic (algorithmic) fashion, Management Algorithms the Paramedic will be able to determine how aggressive an Many algorithms are available for the prehospital provider approach to airway and respiratory management is needed. to use. Some, such as the ASA Diffi cult Airway Algorithm, The Decision to Intubate and/or Provide Respiratory Support do not fi t well in the prehospital environment since they are Algorithm (Figure 21-2) provides the algorithm for patient written for use in a relatively controlled environment of the assessment of airway and respiratory status. operating room and may not be reasonable for the prehospital Although different from a typical algorithm in that each environment.7–9 step is not necessarily an intervention but rather a question to be answered, this algorithm nonetheless systematically Others may contain techniques in which the provider may guides the Paramedic through the steps of assessing a patient’s not be trained. Still others may address only one aspect of airway and respiratory status and is therefore considered to airway management (e.g., intubation) while neglecting other be an algorithm. aspects (i.e., non-intubated management, alternative devices). The algorithm is entered in the upper left-hand corner Ultimately, it is the responsibility of the Paramedic, ALS at the point indicated “Start Here.” Looking at the left-most agency, or medical director to select algorithms for use that column, the fi ve reasons for managing an airway are listed. are suffi ciently comprehensive and refl ect current practice. To As can be seen, they are listed in an order that allows for this end, the following three algorithms are written to provide logical and rapid assessment. In each case, the Paramedic one method for an integrated approach to airway management developed by the author. There has been a traditional separation of “basic life support” and “advanced life support” airway Table 21-1 Indications for Defi nitive skills. Although state rules and regulations dictate the scope Airway Control of EMS practice at all levels, the lines distinguishing these skills have become progressively blurred. • Non-patent airway For example, some EMT-Basics may be allowed to • Inability to maintain a patent airway intubate while some EMT-Paramedics may not be allowed • Failure to oxygenate to place blind insertion airway devices such as the King • Failure to ventilate LTS-D or laryngeal mask airways. Therefore, separating care • Anticipated deterioration in the patient’s status or the airway status into “BLS” and “ALS” algorithms is inappropriate. Instead, 382 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Patient Assesment Initial intervention Ultimate Disposition Start Does the patient have No Do simple maneuvers No • Support ventilation here an open airway? open the airway? • Go to appropriate airway Yes Yes management algorithm Is the patient No Is there a clear and easily No • Support ventilation protecting his airway? reversible disorder (narcotic • Consider Narcan/D50 overdose, hypoglycemia)? • Go to appropriate airway Yes management algorithm Yes Administer Narcan/ No • Support ventilation D50. Successful? • Go to appropriate airway Yes management algorithm No Supplemental oxygen. Is the patient adequately Does oxygenation oxygenating? improve? Yes Yes No No No • Support ventilation Is the patient Consider Narcan/D50 • Go to appropriate airway adequately ventilating? if not already given. management algorithm Yes Consider CPAP Can patient/airway Yes Successful? Consider immediate support status be expected Yes versus observation to deteriorate? and transport No • Provide supplemental oxygen as needed • Transport patient • Constantly monitor patient for airway or respiratory failure Figure 21-2 Decision to intubate and/or provide respiratory support algorithm. asks a “Yes/No” question. If the factor (e.g., an occluded Some patients may have patent airways on primary assess- airway) will not have an impact on the patient’s condition, ment or their airways can be opened with a simple intervention then the Paramedic moves on to the next question. such as a jaw thrust. If the Paramedic determines that the patient If by the end of the question list there are no factors has a patent airway but is unable to maintain that airway, then that would require active airway or respiratory intervention, the provider’s response is determined by the apparent cause of the Paramedic simply monitors and continues to reassess the the disability. These are patients who are typically thought of as patient. By reaching the line of the algorithm that states “unresponsive” but not in cardiac or respiratory arrest. “Provide supplemental oxygen as needed, transport patient, Therefore, hypoglycemia and narcotic overdose need constantly monitor patient for airway or respiratory failure,” to be considered as easily reversible causes of the mental the Paramedic can be assured that immediate airway or status change. If one of these two causes is suspected, then respiratory interventions are not needed. the Paramedic should, if permitted by training and protocol, Only when specifi c conditions exist that would com- attempt to reverse these disease processes. promise a patient’s airway or respiratory status must the If 50% dextrose or naloxone successfully reverses the Paramedic perform interventions. The following evaluates altered mental status, then the patient’s airway maintenance the decision making required and actions to be taken given a issues will often also resolve. Even if hypoglycemia or specifi c condition. narcotic overdose are not clearly the causes of a patient’s If, on primary assessment, a patient does not have mental status change, the provider should consider giving a patent airway, the fi rst intervention is the use of simple these medications prior to more invasive airway management maneuvers. These consist of head-tilt, chin-lift and jaw- if it seems clinically appropriate. thrust maneuvers to lift the epiglottis and soft palate from the If the patient still is not able to maintain the airway, the posterior hypopharynx and pharynx. If these are successful at Paramedic should proceed to the airway algorithm appropriate opening the airway, then the Paramedic should continue the to his level of training. assessment. Otherwise, the Paramedic should move on to the If a patient has a patent airway and is maintaining that appropriate algorithm discussed in the following text. patent airway, it is possible that the patient may still not be The Algorithmic Approach to Airway Management 383 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. effectively oxygenating (transferring oxygen to the tissues) or experience, knowledge of the disease process, ability of the ventilating (removing carbon dioxide from the bloodstream). provider, availability of equipment including medications, A number of disease processes can affect oxygenation and and often discussion with a medical control physician. This ventilation. Typically, a single disease process will affect both. is an important decision to be made and must be done with However, there are disease processes that may cause hypoxia in careful consideration. the face of normal ventilation. Conversely, a patient may have If the patient has a patent airway, is maintaining that adequate tissue oxygenation while retaining carbon dioxide. An airway, is oxygenating and ventilating normally, and is not example of the fi rst is a patient with pneumonia. The patient expected to deteriorate, then the Paramedic has completely may be able to continue to exhale carbon dioxide at a normal assessed the patient’s airway and respiratory status. At this rate but not be able to adequately deliver oxygen to tissues. point, the Paramedic can continue with the remainder of the Rarely will hypoventilation occur without hypoxia. One patient assessment. She should return to reassess the airway example in which it does occur would be a patient with a every few minutes, or sooner if the patient’s status changes. morphine overdose. She may maintain a normal oxygen level If a patient fails any of the fi ve criteria for being able to if given high-fl ow oxygen but still be retaining carbon dioxide manage his own airway, then it is the Paramedic’s responsibility due to decreased respiratory rate or tidal volume. to perform more aggressive interventions. This is the premise By separating oxygenation from ventilation, the Paramedic of the Decision to Intubate and/or Provide Respiratory Support can rapidly screen a patient for oxygenation status and, if it Algorithm. The right-hand column directs the Paramedic to is normal, begin the more focused evaluation of ventilation provide ventilatory support and go to the appropriate airway status. management algorithm. In this case, appropriate refers not to If a patient is found to be hypoxic, the addition of what management would be most appropriate for the patient supplemental oxygen may be adequate to reverse the but rather to the algorithm that is appropriate to the Paramedic’s hypoxia. If supplemental oxygenation reverses the hypoxia, practice level. then the patient should be assessed for ventilation failure. One other important point to remember is the Paramedic If supplemental oxygen is inadequate, however, then the must perform excellent non-intubating airway skills prior patient likely has oxygenation and ventilation failure and to performing excellent intubating airway skills. In an efforts should be made to reverse the ventilation failure. emergency situation, the most experienced Paramedic must For the comatose patient with decreased respiratory rate either perform airway management or directly supervise the or drive, Narcan or 50% dextrose may |
reverse the disease airway management. The Paramedic who divides airway process. For the patient in congestive heart failure or COPD management tasks into ALS and BLS and believes that he is exacerbation, use of continuous positive airway pressure only responsible for ALS skills is mistaken and is providing (CPAP) or bilevel positive airway pressure (BiPAP) may poor patient care. Therefore, it is imperative that the Paramedic overcome the oxygenation or ventilation failure.10,11 However, be comfortable with all aspects of airway management, if the patient remains hypoxic or is hypoventilating in spite including both the “non-intubating” and “intubating” airway of these interventions, more aggressive interventions are management algorithms. needed. The Paramedic should move on to the appropriate airway management algorithm. If a patient has a patent airway, is maintaining that Non-Intubating airway, and is oxygenating and ventilating normally, then Airway Management Algorithm it is unlikely that an immediate, emergent intervention is The “Non-Intubating Airway Management Algorithm” necessary. However, the Paramedic must be knowledgeable (Figure 21-3) is entered at the top with the assumption that an concerning the natural progression of diseases. There are a assessment is complete and the patient is in need of further number of disease processes encountered in the prehospital airway or respiratory support and management. The next environment that can cause a patient, the patient’s airway, or three interventions should all be automatic. The fi rst and most the patient’s respiratory status to deteriorate. A few examples important intervention is to minimize or prevent hypoxia. include airway burns, congestive heart failure, asthma Hypoxic brain death occurs within 6 to 10 minutes of apnea exacerbation, and sepsis. or signifi cant hypoxia. In each of these cases, the Paramedic must make an Therefore, immediate application of high-fl ow oxygen is important decision as to whether to intervene immediately mandatory to provide as much of a time margin as is possible. or to monitor the patient. Several conditions (e.g., airway and Ideally, since the patient is at least in ventilatory failure and inhalation burns with dyspnea, stridor, or hoarseness) are at worst is apneic, the oxygen will be applied through a bag- almost absolutely guaranteed to progress to airway occlusion valve-mask (BVM) device or, if the patient is apneic, with an and mandate early intubation. automatic transport ventilator (ATV). This may be delegated Patients in congestive heart failure, on the other hand, to another provider so the Paramedic can continue down the may improve dramatically after treatment even with hypoxia algorithm. or hypoventilation during the primary assessment. The The second automatic task is to assemble airway decision to perform early airway management is based on management equipment. The equipment will depend on what 384 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Patient assessment: Patient needs airway/respiratory support Preoxygenate, prepare equipment. Call for back-up if anticipated difficult airway Yes Open the airway/attempt ventilation: • Listen to patient’s Successful? lungs, watch chest No movement. • Insert airway. Reassess provider, patient, and • Transport patient. equipment. Insert airway. Suction/obstruction management PRN. Yes Attempt ventilation: Successful? • Listen to patient’s No lungs, watch chest movement. Reconsider obstruction. Suction. • Insert airway. Perform obstructed airway skills • Transport patient. Yes Attempt ventilation: Successful? • Listen to patient’s No lungs, watch chest movement. Transport patient emergently. • Insert airway. Consider requesting • Transport patient. physician intercept. Figure 21-3 Non-intubating airway management algorithm. skills the Paramedic is able to perform, but should ideally be Table 21-2 Conditions Requiring available in a single bag or box and be organized, complete, Emergency Transportation and up-to-date. Once these tasks have been accomplished, the next step • Abnormal vital signs that cannot be corrected/do not respond to treatment is to begin supporting the patient. Opening the airway and providing ventilation is the fi rst step in supporting the patient. • Unmanageable airway If the patient is spontaneously but ineffectively breathing, then • Ischemic compromise of an extremity supported ventilations with a BVM is the most appropriate • Complicated delivery intervention. • Uncontrollable bleeding If the patient is apneic, then either a BVM or an autom- • Cardiac arrest reversal with abnormal vital signs atic transport ventilator attached to a mask can be used. If the • Cardiac arrest without defi brillation/medications available Paramedic is successful at opening the airway and providing ventilation, then a rapid assessment of the intervention’s adequacy is performed (auscultation, observation). Either for emergent transport may be too high. In that case, the an oropharyngeal or a nasopharyngeal airway is inserted Paramedic should consider non-emergency transport. If the depending on the absence or presence of a gag refl ex, patient’s airway cannot be managed, however, then the patient respectively. Finally, the patient is transported. should be transported emergently. This approach is taken by Note that in both the intubating and non-intubating the “intubating” and “non-intubating” algorithms. In reality, algorithms, there are distinctions made between transport the decision will be made based on local protocols, local and transport emergently. These differences are based on standard of care, and medical direction. a specifi c list of conditions (Table 21-2), which require There will be times when a patient’s airway cannot be emergent transport (the assumption being that for all other established or the patient cannot be ventilated on the fi rst conditions, the risks of emergent transport may outweigh any attempt. If this is the case, the Paramedic must quickly benefi ts). troubleshoot. Immediate actions should include repositioning If a patient’s vital signs are otherwise stable and the airway the patient’s head and, if needed, suctioning the airway and and ventilation adequately managed, the risk-to-benefi t ratio performing obstructed airway skills. The Algorithmic Approach to Airway Management 385 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Once these interventions are performed, the Paramedic should make a second attempt to open the airway and ventilate Cultural / Regional differences the patient. If the second attempt is successful, then, as before, the Paramedic should assess the adequacy of ventilation, insert an oropharyngeal (OP) or nasopharyngeal (NP) airway, and In some regions, prehospital physician intercepts are transport the patient. possible and, if available, should be requested at If, after the second attempt, the Paramedic is unable to this time as well. If these intercepts will increase the establish a patent airway or ventilate the patient, an obstruction time to defi nitive care (e.g., physician, emergency should be assumed. The appropriate obstructed airway management skills (Heimlich maneuver, unconscious patient department, or operating room), then they should not abdominal thrusts, chest thrusts, or back blows) should be occur and the patient should be emergently and safely performed and another attempt should be made to ventilate transported. The Paramedic should not wait on-scene the patient. If this attempt is successful, then the Paramedic should assess the adequacy of ventilation, place an OP or for an EMS Physician to arrive. NP airway, and transport the patient. If, however, the third attempt at ventilation fails, then a change in tactics must be made. An analysis of the actions performed gives insight into Intubating Airway Management why, after three ventilation attempts, the Paramedic should Algorithm change tactics. As with the Non-Intubating Airway Management Algorithm, When the fi rst attempt is made to ventilate the patient, a patient enters the Intubating Airway Management Algorithm it is assumed that the patient has normal anatomy and that by virtue of having met one of the fi ve criteria for airway and “normal” (not including foreign body obstruction) causes of respiratory management and by having a Paramedic capable respiratory and airway failure have occurred. In most of these of intubating and performing other advanced airway skills. patients, a head-tilt, chin-lift or jaw thrust, in combination The top of the algorithm (Figure 21-4) is the entrance point with BVM or ATV ventilation, will be adequate to open the and assumes that the patient needs to be intubated. As will be airway and provide ventilation. recalled, other non-intubated ventilatory support modalities If these interventions fail, the next intervention is to should have been tried by this point. The algorithm directs rapidly troubleshoot and correct easily identifi able problems, the Paramedic toward a goal: a secure airway with adequate including inadequate performance of skills, on the fi rst ventilation. ventilation attempt. Therefore, when the second attempt is The Paramedic places the patient on high-fl ow oxygen or made at ventilation, the Paramedic will still assume the patient ventilates the patient with a BVM. At this point, if possible, the has normal anatomy and “normal” causes of the airway and most experienced Paramedic should be performing or directly respiratory failure. In most of the remaining patients, these supervising the patient’s care. While the Paramedic is doing this, few corrections will open the airway and allow adequate the least experienced Paramedic on the scene, who is capable of assisted ventilation. preparing the intubation and airway management equipment, If the second attempt at ventilation fails, however, the should be doing so. Having the most experienced providers Paramedic must consider abnormal conditions. Therefore, directly managing the patient’s care will optimize that care. between the second and third ventilation attempts, the While there is some debate as to the defi nition of Paramedic performs all of his skills to correct or compensate an intubation attempt, the National Association of EMS for anatomical issues, airway obstruction, and physiological Physicians (NAEMSP) developed a standardized reporting defects. The Paramedic corrects all the variables for which tool (Table 21-3). As each unsuccessful intubation attempt he is able to compensate. The third attempt at ventilation, will cause edema, bleeding, and patient deterioration, it therefore, is an optimized attempt.12 If this attempt fails, there is important that the fi rst intubation attempt be the best is little else the Paramedic can do. Therefore, after the third intubation attempt.13 Conditions must be optimized through attempt, a different tactic must be taken. proper, working equipment and, if used, drug selection. The The failure of the third ventilation attempt signifi es that patient must be correctly positioned, the Paramedic must be the Paramedic has no additional changes in care to offer. correctly positioned relative to the patient, and lighting should Therefore, the patient must be transported immediately to be controlled as much as possible. The proper route must be another provider capable of offering additional, advanced selected. In short, everything that can be controlled should be care. These are critically unstable patients and should so as to make the fi rst attempt most likely to succeed. be transported emergently. During that transport, the Once the equipment is prepared and conditions are Paramedic should continue to perform obstructed airway optimized, the route must be selected. For a breathing patient, skills and attempt to ventilate. If it will shorten the time to particularly one with a primary respiratory disease such as access advanced care, ALS providers should intercept the CHF or a COPD exacerbation, nasal intubation is an excellent transport. choice.14–18 These patients are likely to become hypoxic 386 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Patient assessment: Patient needs to be intubated Preoxygenate, ventilate PRN, prepare equipment If patient is breathing, consider nasal intubation Yes Attempt orotracheal intubation: • Confirm position Successful? with 3 methods. No |
• Secure tube. • Monitor patient. Ventilate. Reassess provider, patient, and equipment. • Confirm position with 3 methods. Yes • Secure tube. Attempt intubation (x 2): Successful? • Monitor patient. No Ventilate, prepare Blind Insertion Airway Device • Confirm position Yes with 3 methods. Attempt BIAD placement: Successful? • Secure tube. No • Monitor patient. Attempt to ventilate with BVM/ATV: Yes Monitor patient, Successful? transport No emergently Consider obstructed airway. If unable to clear Yes Monitor patient, obstruction, attempt surgical airway: Successful? transport No emergently Transport patient emergently. Consider requesting physician intercept. Figure 21-4 Intubating airway management algorithm. Table 21-3 NAEMSP Defi nition First, auscultate over the epigastrium while the patient is of Intubation Attempt ventilated. If the endotracheal tube is correctly placed in the trachea, there should be an absence of gastric sounds. Next, 1. Insertion of laryngoscope blade into mouth (for orotracheal auscultate over both the left and right lung fi elds for presence methods) of equal breath sounds. If the right lung sounds are louder than 2. Insertion of tube through nares of nose (for nasotracheal methods) the left, the endotracheal tube is likely in the right mainstem 3. Insertion of rescue airway device into mouth (for Combitube, LMA, bronchus. Check depth of endotracheal tube placement and and other oral rescue airway devices) withdraw the tube by 1 or 2 cm, reinfl ate the balloon, and 4. Insertion of rescue airway devices through the neck (for reassess lung sounds. If the lung sounds remain unequal, then cricothyroidotomy, needle jet ventilation, retrograde ETI, and other assess the patient for a pneumothorax, as discussed in later “surgical” methods of airway management) chapters. H.E. Wang, R.M. Domeier, D.F. Kupas, M.J. Greenwood, R.E. O’Connor, The two commonly accepted additional methods of “Recommended guidelines for uniform reporting of data from out-of-hospital airway management: position statement of the National Association of EMS confi rming tube placement are esophageal detector devices Physicians,” Prehospital Emergency Care 8, no.1 (2004): 58–72. and colorimic end-tidal carbon dioxide measurement.19–21 Each of these methods has benefi ts and drawbacks. Using two or three tend to cancel out the problems inherent in each rapidly if medications are used to sedate or paralyze them as method. they have no reserve capacity. If the patient is not breathing, Once the endotracheal tube is confi rmed to be in a tracheal however, or has evidence of a basilar skull fracture, then an position, it must be secured using either a commercial device or attempt at oral intubation is the next step. tape. Additionally, the use of a cervical immobilization collar After the endotracheal tube is passed, tube position is and cervical immobilization device (head blocks) will minimize confi rmed by auscultation and another confi rmation device. tube movement and the potential for displacement. The use of The Algorithmic Approach to Airway Management 387 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. waveform capnography in the intubated patient can provide an having a tube beyond the vocal cords with direct access to additional layer of safety as endotracheal tube dislodgement can the trachea, it is more secure than with simple face-mask be identifi ed and corrected almost immediately. The Paramedic ventilation. There will be occasions when these devices will must continue to monitor the patient for changes in respiratory not provide adequate ventilation. For example, in a patient status and transport the patient. with an inhalation burn and vocal cord edema, none of these If the fi rst intubation attempt fails, however, then the devices can guarantee that air will pass through the cords to Paramedic must reconsider his actions and determine adequately ventilate the patient. However, as noted before, the best course to increase the chances of success on the failure to provide some improvement in ventilation is rare. second attempt. Sometimes it is possible to identify a single Once the BIAD is in place, it needs to be confi rmed. item that caused the intubation attempt to fail, such as In this case, auscultation and end-tidal carbon dioxide laryngoscope light failure, insuffi cient suction, or the need measurement can be utilized. Esophageal detection devices for sedation and/or paralysis. Other times, the Paramedic will not necessarily work with any of the BIADs. Therefore, simply recognizes that a different approach must be tried monitoring the patient’s condition over time becomes the without being completely sure why the fi rst approach failed. third method of confi rming device placement. Once the Therefore, if the fi rst intubation attempt failed, the patient placement has been confi rmed, the BIAD must be secured must be ventilated as needed and the Paramedic must attempt in the manner recommended by the manufacturer and the to optimize the subsequent intubation attempt. The changes patient should be monitored and transported. If the patient made to optimize the second attempt should be based on the has no other concurrent issues and the BIAD is allowing for fi ndings of the fi rst attempt. adequate oxygenation and ventilation, then a non-emergency Once the Paramedic is ready to reattempt intubation, no mode transport may be appropriate. more than two more attempts should be made to intubate the If the BIAD will not pass (for anatomical reasons, injuries, patient. If, after a total of three attempts, the patient is not etc.) or does not seem to be providing adequate ventilation, intubated and no clearly correctable problem is identifi ed, then then the Paramedic must fall back on the fundamentals of a different approach to the specifi c patient is required. By the airway management. The objective of airway management is time the third attempt has been made, the Paramedic should to allow adequate oxygenation and ventilation. have maximized conditions. In all likelihood, further attempts Therefore, if all previous methods of securing the will result only in more bleeding and edema and a more airway have failed, then face-mask ventilation with a BVM diffi cult airway to manage. The greater the number of attempts or ATV and an oropharyngeal or nasopharyngeal airway is at endotracheal intubation, the lower the chance of success.22 appropriate. There will be patients whose airways cannot If the second or third intubation attempt is successful, then otherwise be managed due to injury or anatomy who will the tube should be confi rmed with three methods, it should be do well with face-mask ventilation. If the patient can be secured, and the patient should be monitored and transported. adequately ventilated by these interventions, then the patient If these two additional attempts are not successful, however, should be monitored and transported. These patients with then the airway manager must move on with his management clearly diffi cult airways will usually qualify for emergent plan. The patient should be ventilated as needed. transport. If the patient improves and remains stable with The next class of devices that are likely to succeed in at face-mask ventilation alone, however, non-emergent transport least partially securing the airway are devices designed for can be considered. blind insertion into the upper portion of the airway above the If all other airway management modalities have failed and glottis. Several terms have been used to describe these devices, the patient still cannot be ventilated, then the Paramedic must including supraglottic airway devices, non-visualized airway assume that there is a pathological obstruction of the airway. devices, and blind insertion airway devices (BIADs). For the This obstruction may be visualized during an intubation remainder of this discussion, we will use the term BIADs attempt or assumed from either the patient’s disease process when referring to these airways. The BIADs commonly or simply from the failure to ventilate. If basic and advanced used include the King LTS-D airway, laryngeal mask airway obstructed airway skills do not clear the airway, then the (LMA), and the esophageal tracheal Combitube. Each of Paramedic is left to attempt to establish a surgical airway. If these devices has its strengths and weaknesses. In general, the the pathology is at the level of the thyroid cartilage or above, a esophageal obturator airway (EOA) and esophageal gastric surgical airway will allow ventilation and oxygenation. If the tube airway (EGTA) should rarely be considered as they obstruction is at or below the level of the trachea, however, a have a history of high complication rates and both require surgical cricothyrotomy will most likely fail. maintenance of a mask seal during use. Although they are If the surgical airway succeeds, the patient should be still the BIADs of choice for some agencies, standard of care monitored and transported emergently. If, however, the is moving away from the EOA and EGTA and toward one of surgical airway fails, then the patient must be transported the other devices. emergently while the Paramedic attempts to oxygenate and It is rare that a blind insertion airway device will not ventilate the patient. If available, the Paramedic may consider provide at least some ability to effectively ventilate a patient. a physician intercept or an intercept with a more experienced Although the airway may not be secure in the sense of Paramedic while en route to the hospital. 388 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Airway management can be one of the most life-saving tasks a Paramedic can perform for a patient. As has been demonstrated in the cardiopulmonary resuscitation arena, algorithms can greatly enhance consistent and correct task performance during life-threatening emergencies. The value of an algorithmic approach to airway management has been recognized by professional organizations. Although the use of algorithms can greatly facilitate airway management, it is important to recognize that the algorithm is written for the majority of situations and that algorithms are not “one size fi ts all.” Therefore, the Paramedic must recognize that an algorithm is simply one more tool to improve the quality of patient care. While it does not replace clinical judgment in a specifi c situation, it allows a systematic approach that will enhance patient care. Key Points: • The algorithm is a form of preplanning in an • Despite having a patent airway, it is possible that emergency situation. the patient may still not be effectively oxygenating or ventilating. • Emergency airway algorithms all begin with a patient in need of airway and ventilation management. • If the patient with a patent airway is maintaining that airway, is oxygenating and ventilating • The Paramedic must determine what degree of normally, and is not expected to deteriorate, airway management and respiratory support is then the Paramedic has completely assessed the needed for every patient. patient’s airway and respiratory status. She should • Active airway or respiratory management is continue monitoring for effect. required for each of the following: • The “Non-Intubating Airway Management ■ Non-patent airway Algorithm” addresses the need for airway or ■ Inability to maintain patient’s own airway respiratory support and management, which is the ■ Failure to oxygenate fi rst and most important automatic intervention to ■ Failure to ventilate minimize or prevent hypoxia. ■ Anticipated deterioration of the patient’s status or the airway status • The second automatic task is to assemble airway management equipment appropriate to the • If, on primary assessment, a patient does not have a Paramedic’s skill level. patent airway, the fi rst intervention is the use of a head-tilt, chin-lift or jaw-thrust maneuver to open • The Paramedic should support the patient with the airway. If the patient has a patent airway but ineffective breathing or apnea by opening the is unable to maintain that airway, the Paramedic airway and providing ventilation. should determine the cause of the disability. • The following |
conditions require emergent • Hypoglycemia or narcotic overdose should be transport: considered when presented with patients who are ■ Abnormal vital signs that cannot be corrected/ typically thought of as “unresponsive” but not in do not respond to treatment cardiac or respiratory arrest. ■ Unmanageable airway The Algorithmic Approach to Airway Management 389 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. ■ Ischemic compromise of an extremity ■ Complicated delivery • After the endotracheal tube is passed, tube position is confi rmed by auscultating fi rst over the ■ Uncontrollable bleeding epigastrium, then over the left and right lung fi elds ■ Cardiac arrest reversal with abnormal vital signs for presence of equal breath sounds. ■ Cardiac arrest without defi brillation/medications available • The Paramedic confi rms placement with at least If the patient’s airway cannot be managed, the one additional method. Waveform capnography is patient should be transported emergently. required in many EMS systems. • The Paramedic should consider suctioning and • The Paramedic should note the depth of the repositioning the head as initial interventions for a endotracheal tube placement and secure the patient who cannot be ventilated. endotracheal tube with tape or a commercial • device. If a second attempt is successful, the Paramedic should consider an OPA or NPA along with patient • The Paramedic should use a cervical immobilization transport. device to minimize tube movement and potential • for displacement. If a second attempt is unsuccessful, an obstruction should be assumed. The Paramedic should perform • The Paramedic should continue monitoring the the appropriate obstructed airway management patient for effect. skills (Heimlich maneuver, unconscious patient abdominal thrusts, chest thrusts, or back blows) and • If the fi rst intubation attempt fails, the patient must make another attempt to ventilate the patient. be ventilated. No more than two more attempts should be made to intubate the patient. • Continued failure to ventilate is an abnormal circumstance requiring all measures available to • Blind insertion airway devices (BIADs) are likely to obtain a patent airway, including transporting succeed in at least partially securing the airway the patient to a provider capable of offering an and are designed for blind insertion into the upper advanced level of airway care. portion of the airway above the glottis. • Conditions prior to the fi rst intubation attempt must • Once the BIAD is in place, the Paramedic should be optimized by fi rst selecting the proper provider, confi rm it by auscultation, end-tidal carbon dioxide equipment, medications, and route. The Paramedic measurement, or simply monitoring the patient’s and patient must also be in proper positions with condition over time. suffi cient lighting. • An obstruction may be visualized during an • Nasal intubation is an excellent choice for the intubation attempt or assumed from either the spontaneously breathing patient with a respiratory patient’s disease process or the failure to ventilate. disease history. • A surgical airway is often considered the last • Oral intubation is a good choice for an apneic patient course of action that may allow ventilation and or one with a suspected basilar skull fracture. oxygenation. 390 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Review Questions: 1. Contrast the “if-then” approach of protocols Algorithm before using the Intubating Airway with the methodology that algorithms offer. Management Algorithm? 2. What criteria are used to make a patient’s 6. What are the automatic tasks the Paramedic transport decision? should perform under the Non-Intubating 3. What are two easily reversible conditions where Airway Management Algorithm? the patient is thought of as “unresponsive” but 7. What are the fi ve reasons for which a patient not in cardiac or respiratory arrest? may require active airway or respiratory 4. Provide a disease process for each situation: a management? patient who is hypoxic with normal ventilation 8. After the endotracheal tube is passed, how is and a patient who has adequate tissue tube position confi rmed? oxygenation but is retaining carbon dioxide due 9. What should the Paramedic do if the fi rst to ventilatory failure. intubation attempt fails? 5. Why should the Paramedic have mastered 10. Describe the function of a blind insertion airway the Non-Intubating Airway Management device. Case Study Questions: Please refer to the Case Study at the beginning of the adequately ventilate the patient? Explain your chapter and answer the questions below: answer. 1. What early interventions can be performed to 3. How would you assess the success of the increase the likelihood of successful ventilation placement? for this patient? 4. What other devices/interventions are available 2. What airway device would you choose for the provision of adequate airway/ventilation? if the providers remained unable to References: 1. Combes X, Jabre P, Jbeili C, Leroux B, Bastuji-Garin S, 4. Gerich TG, Schmidt U, Hubrich V, Lobenhoffer HP, Tscherne Margenet A, et al. Prehospital standardization of medical airway H. Prehospital airway management in the acutely injured management: incidence and risk factors of diffi cult airway. Acad patient: the role of surgical cricothyrotomy revisited. J Trauma. Emerg Med. 2006;13(8):828–834. 1998;45(2):312–314. 2. Dorges V, Wenzel V, Knacke P, Gerlach K. Comparison of 5. Bishop MJ. Practice guidelines for airway care during different airway management strategies to ventilate apneic, resuscitation. Respir Care. 1995;40(4):393–401; discussion 401. nonpreoxygenated patients. Crit Care Med. 2003;31(3):800–804. 6. Candido KD, Saatee S, Appavu SK, Khorasani A. Revisiting 3. Hoyle JD, Jr., Jones JS, Deibel M, Lock DT, Reischman D. the ASA guidelines for management of a diffi cult airway. Comparative study of airway management techniques with Anesthesiology. 2000;93(1):295–298. restricted access to patient airway. Prehosp Emerg Care. 7. Timmermann A, Russo SG. Which airway should I use? Curr 2007;11(3):330–336. Opin Anaesthesiol. 2007;20(6):595–599. The Algorithmic Approach to Airway Management 391 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. 8. Ezri T, Szmuk P, Warters RD, Katz J, Hagberg CA. Diffi cult 17. Arora MK, Karamchandani K, Trikha A. Use of a gum elastic airway management practice patterns among anesthesiologists bougie to facilitate blind nasotracheal intubation in children: a practicing in the United States: have we made any progress? J series of three cases. Anaesthesia. 2006;61(3):291–294. Clin Anesth. 2003;15(6):418–422. 18. Butcher D. Pharmacological techniques for managing acute pain 9. Ron M, Walls R, Michael F, Robert C, Robert E. Manual of in emergency departments. Emerg Nurse. 2004;12(1):26–35; Emergency Airway Management. Hagerstwon: Lippincott quiz 36. Williams & Wilkins; 2004. 19. Hayden SR, Sciammarella J, Viccellio P, Thode H, Delagi 10. Hunjadi D. From provider to patient. Emerg Med Serv. R. Colorimetric end-tidal CO detector for verifi cation of 2 2005;34(8):157–160. endotracheal tube placement in out-of-hospital cardiac arrest. 11. Goss JF, Zygowiec J. Positive pressure: CPAP in the treatment of Acad Emerg Med. 1995;2(6):499–502. pulmonary edema & COPD. Jems. 2006;31(11):48, 50, 52–58 20. Cummins RO, Hazinski MF. Guidelines based on the principle passim; quiz 64. “First, do no harm.” New guidelines on tracheal tube confi rmation 12. Wang HE, Yealy DM. How many attempts are required to and prevention of dislodgment. Resuscitation. 2000;46(1–3): accomplish out-of-hospital endotracheal intubation? Acad Emerg 443–447. Med. 2006;13(4):372–377. 21. Zaleski L, Abello D, Gold MI. The esophageal detector device. 13. Butler KH, Clyne B. Management of the diffi cult airway: Does it work? Anesthesiology. 1993;79(2):244–247. alternative airway techniques and adjuncts. Emerg Med Clin 22. Wang HE, Domeier RM, Kupas DF, Greenwood MJ, O’Connor North Am. 2003;21(2):259–289. RE. Recommended guidelines for uniform reporting of data from 14. Iserson KV. Blind nasotracheal intubation. Ann Emerg Med. out-of-hospital airway management: Position statement of the 1981;10(9):468–471. National Association of EMS Physicians. Prehosp Emerg Care. 15. Danzl DF, Thomas DM. Nasotracheal intubations in the 2004;8(1):58–72. emergency department. Crit Care Med. 1980;8(11):677–682. 16. O’Brien DJ, Danzl DF, Hooker EA, Daniel LM, Dolan MC. Prehospital blind nasotracheal intubation by Paramedics. Ann Emerg Med. 1989;18(6):612–617. 392 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Public Health and the Paramedic 393 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. KEY CONCEPTS: Upon completion of this chapter, it is expected that the reader will understand these following concepts: • The benefi ts of preoxygenation for any patient in need of active airway management or ventilatory support • The use of cricoid pressure during manual ventilation • Simple airway maneuvers that can make all the difference • Understanding ventilatory pressure and reducing gastric infl ation • Indications and application of continuous positive airway pressure (CPAP) • Assessing the adult and pediatric patient for appropriate oxygenation and ventilation Case Study: The Paramedics were called to the home of Mrs. Tedesco, an elderly woman with a lengthy history of congestive heart failure. When they arrived, Mrs. Tedesco’s breathing appeared worse than usual. One Paramedic placed her on a nonrebreather mask but she continued to labor. 394 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Non-Intubating Airway Management 395 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. OVERVIEW Knowledge and skill in basic airway management is mandatory. Often some of the most basic techniques are the most critical and fundamental airway management skills a Paramedic can perform. This chapter addresses a number of skills and simple devices the Paramedic can utilize to effectively ventilate patients through simple face- mask techniques. In addition, continuous positive airway pressure (CPAP) and other advances in airway technology allow critically ill patients to be managed without the need for intubation. Basic Airway Management Using the Non-Intubating Airway Management Algorithm (Figure 22-1) as a guide, this chapter will review Basic airway management is one of the most critical the fundamentals of basic airway skills. In addition, tech- and fundamental skills an emergency medicine pro- niques to avoid intubation, such as CPAP and assisted venti- vider can possess.1–3 Whether that provider is an EMT, lation, will be discussed. a Paramedic, |
a nurse, or a physician, knowledge and skill in basic airway management is critical. As stated suc- cinctly in the 1994 EMT national standard curriculum, “a patient without an airway is a dead patient.” Although Street Smart the knowledge and skill to perform intubations and other advanced airway maneuvers, as described in the next chapter, are a critical part of the Paramedic’s practice, Correct positioning of the patient and the airway is the non-invasive, basic skills are truly the most critical the most basic airway maneuver. to master. Patient assessment: Patient needs airway/respiratory support Preoxygenate, prepare equipment. Call for back-up if anticipated difficult airway Yes Open the airway/attempt ventilation: • Listen to patient’s Successful? lungs, watch chest No movement. • Insert airway. Reassess provider, patient, and • Transport patient. equipment. Insert airway. Suction/obstruction management PRN. Yes Attempt ventilation: Successful? • Listen to patient’s No lungs, watch chest movement. Reconsider obstruction. Suction. • Insert airway. Perform obstructed airway skills • Transport patient. Yes Attempt ventilation: Successful? • Listen to patient’s No lungs, watch chest movement. Transport patient emergently. • Insert airway. Consider requesting • Transport patient. physician intercept. Figure 22-1 Non-intubating airway management algorithm. 396 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. The Basic Airway Management systems, the fl ow meter is generally separate from the regula- tor. Oxygen fl ow rates range from 0.5 to 25 LPM. In addi- Algorithm tion, many regulators can deliver a 50 PSI source of oxygen By the time the Paramedic enters the basic algorithm, the for various devices (e.g., ventilators, continuous and bilevel decision has already been made to provide airway and ven- positive airway pressure, and trans-tracheal jet ventilation tilatory support to the patient. Once that decision has been equipment). made, the Paramedic must proceed in an orderly manner Oxygen is delivered to the patient from the regula- through the steps of care. tor through a number of devices. The most commonly used devices are the nasal cannula, the simple face mask, and the Preoxygenation nonrebreather mask. In addition, demand valve devices also provide a method for providing high concentration oxygen Any patient in need of active airway management or ventila- but are less commonly used. tory support is in need of supplemental oxygen. Providing a The nasal cannula is a pronged device designed for nasal patient with supplemental oxygen serves a number of pur- oxygen delivery (Figure 22-2). With oxygen fl ows from 0.5 poses. Supplemental oxygen replaces nitrogen in the dead to 6 LPM, these devices can deliver up to a 40% FiO . They space of the lungs with oxygen, referred to as nitrogen wash- 2 are generally well tolerated and do not require a patient to out. Not only does this increase the diffusion gradient, causing breathe through his nose to be effective. Only complete bilat- more oxygen to dissolve into the plasma, but it also provides eral nasopharyngeal obstruction would prevent oxygen deliv- a “reservoir” of oxygen in the lungs in the event the patient ery. Indications include the need for supplemental oxygen. becomes apneic.4,5 Oxygen can often decrease the patient’s Contraindications include severe hypoxia, apnea, and intoler- respiratory distress, in turn decreasing catecholamine release ance of the device. and myocardial oxygen demand. The high-fl ow nasal cannula (HFNC) is an advance in Oxygen Delivery Devices nasal cannula technology. By humidifying and warming the oxygen, and using membrane technology, the device is able Oxygen equipment includes oxygen storage devices, regula- to comfortably deliver up to 40 LPM to the patient through tors, and delivery devices (i.e., masks, nasal cannula). It is a nasal cannula. Although this technology has not yet been important that the Paramedic be skilled in the use of these applied in the prehospital environment, it does offer some devices. promise. Oxygen is stored as either a compressed gas, in steel or The simple face mask is a low- to mid-concentration aluminum tanks, or as a liquid. Common compressed gas oxygen delivery device. The mask seals over the mouth and cylinders in the prehospital environment include D cylinders, nose, delivering oxygen through an input port and drawing which hold 400 L of oxygen when completely fi lled; E cyl- air through an open side port. At 10 LPM, a 40% to 60% FiO 2 inders, which hold 660 L of oxygen; and M cylinders, which is attained.8 Unfortunately, increasing the oxygen fl ow above hold 3,450 L.6,7 Since the cylinders contain oxygen at high 10 LPM does not signifi cantly increase FiO since the same 2 pressure (1,800 PSI), it is important that they be handled with amount of room air will still be drawn through the side port on care to prevent damage to the valve. inspiration. Additionally, leaks around the mask will decrease Oxygen can also be chilled or compressed at high the FiO . These masks are not used as commonly as the next 2 pressures and stored in a liquid form. Although liquid class, the nonrebreather mask. oxygen (LOX), concentrated oxygen in liquid form, sys- tems permit large volumes of oxygen to be stored in a relatively small space, there are several disadvantages to these systems. The tanks must be stored upright and spe- cial equipment is required for storage and cylinder transfer. Additionally, anecdotal reports suggest that, due to sys- tem leakage, unless the oxygen is used in a high volume agency, oxygen losses may exceed usage. Therefore, com- pressed oxygen cylinders are the most common method of storing oxygen in the prehospital environment. Oxygen cannot safely be administered at the high pres- sure at which it is stored (500 to 1,800 PSI). Instead, a regula- tor is used to decrease the pressure to a tolerable level. In addition, since oxygen is usually delivered in a con- tinuous fl ow rather than on-demand, regulators are coupled with fl ow meters to deliver a fi xed fl ow, measured in liters per minute (LPM). For portable regulators, the regulator and fl ow meter are integrated, while for fi xed (on-board) oxygen Figure 22-2 Nasal cannula. Non-Intubating Airway Management 397 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. A demand valve regulator is a device available that will provide 100% FiO at appropriate liter fl ows. When attached to 2 a 50 PSI oxygen source, this device delivers high LPM fl ows of 100% oxygen when the patient inhales. When the patient is exhaling, the valve closes and oxygen fl ow stops. This device is different from a manually triggered ventilation device in that it is the patient’s inspiratory effort that triggers the device. Therefore, the risk of over pressurization injury is minimized. However, the device cannot be used in apneic patients. Venturi masks, special masks with a restricted intake that permits an exact percentage of oxygen, can also be used to deliver oxygen, although their use in the prehospital environment is gen- erally limited to specialty care services. These devices use a face mask connected to a specially designed adapter. These adapters have small holes in the sides and are designed so that when a specifi c oxygen liter fl ow is delivered to the adapter, a specifi c amount of room air is drawn into the adapter as well, called the venturi effect. This mixing provides a very specifi c oxygen con- centration. Generally speaking, unless a patient is already using a venturi mask and is not hypoxic or is on a fi xed FiO during a 2 specialty transport, there are no indications for the prehospital use of the venturi mask. Generally speaking, patients can be thought of as being at minimal risk for hypoxia, at moderate risk for hypoxia, or hypoxic. Patients at minimal risk for hypoxia may ben- efi t from a nasal cannula, depending on the patient’s clini- cal condition. Patients at moderate risk for hypoxia or who are hypoxic should receive high-concentration oxygen (i.e., a Figure 22-3 Nonrebreather face mask. nonrebreather mask). Any patient who requires active airway management should be preoxygenated with a nonrebreather Nonrebreather face masks (Figure 22-3) are designed to mask. Once the patient is being oxygenated, the remainder of overcome the issue of room air dilution by adding a reservoir the basic airway management equipment should be prepared to the oxygen supply system. While oxygen fl ows, it simul- to address ventilations. taneously supplies oxygen into the mask and into a reservoir bag. When the patient exhales, a one-way valve seals and Equipment for Basic Airway the oxygen is directed into the reservoir. When the patient Management inhales, the one-way valve opens and the patient breathes the oxygen from the reservoir. There are multiple methods for opening the airway and ven- Although a normal adult male may have a minute ventila- tilating a patient who is in respiratory distress or respiratory tion of 6 to 8 LPM, this ventilation occurs during inhalation arrest. A number of techniques can be used to manually open and airfl ow is not continuous. The fl ow during inhalation may the airway. Devices, such as oropharyngeal and nasopharyn- approach 50 LPM!9 Oxygen delivery from a regulator, on the geal airways, can be used to help maintain an open airway. other hand, is continuous and limited to the liter fl ow settings The most commonly used device for providing ventilatory on the regulator. The reservoir bag on the nonrebreather mask assistance is the bag-valve-mask assembly. When used prop- supplies the additional liter fl ow required during inhalation by erly, these devices can effectively be used to ventilate most storing oxygen during exhalation. This is why it is important patients. Other devices such as the pocket mask, the manu- that the liter fl ow is set high enough that the reservoir bag does ally triggered oxygen-powered ventilator, and the automatic not collapse during inhalation. Most nonrebreather face masks transport ventilator are also available to provide ventilation. have two exhalation ports, at least one of which is left open. Furthermore, suction is an important and frequently over- If the reservoir bag is collapsing during inhalation, room air is looked adjunct to airway management. drawn through the side port to prevent rebreathing of carbon dioxide. Oropharyngeal and Nasopharyngeal Nonrebreather face masks (NRFM), oxygen masks Airways with an oxygen reservoir, can deliver up to 80% FiO ; they Some of the most fundamental and easiest to use devices 2 do not deliver 100% FiO because there will always be some for airway management are the oropharyngeal and nasopha- 2 room air mixing through the open side port. ryngeal airways. As discussed in Chapter 20, the most 398 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Figure 22-5 Nasopharyngeal airway. Figure 22-4 Oropharyngeal airway. common anatomic structures obstructing the airway are the Although the nasopharyngeal airway is less likely to stimu- soft palate and the epiglottis. Since the epiglottis is attached late a gag refl ex, patients may vomit or sneeze after nasopharyn- to the hyoid bone by the hyoepiglottic ligament, anterior geal airway placement. Therefore, suction must be immediately displacement of the hyoid opens the airway. The hyoid is available when a nasopharyngeal airway is placed. indirectly attached to the tongue, and anterior displacement There are a number |
of advantages to the placement of of the tongue facilitates anterior displacement of the hyoid. the nasopharyngeal airway. These include the ability to place Additionally, the tongue can increase airway turbulence by them in patients with trismus or in those who are otherwise narrowing the upper airway. The oropharyngeal airway is unable to open their mouths. Nasopharyngeal airways can designed to address this issue.10,11 The nasopharyngeal air- also be used in patients who have an intact gag refl ex. way helps to displace the soft palate anteriorly, improving The only true contraindication to the placement of the airfl ow through the upper airway. Neither the oral airway nasopharyngeal airway is the patient’s inability to tolerate the nor the nasopharyngeal airway provide protection against airway. Care must be taken if it is being used in someone with a aspiration.12 head injury. Make sure that there is no evidence of a basilar skull Oral airways come in a number of sizes, from neonatal fracture, as there is some risk, although very slight, of placing to large adult (Figure 22-4). Preparation of an oropharyn- the airway into the cranium.15–20 In addition, patients with bleed- geal airway involves measuring the appropriate size for the ing disorders or who are on blood thinners are at risk of signifi - patient. Two common methods are used. The fi rst is to mea- cant epistaxis from nasopharyngeal airway placement. sure the airway from the midline of the lips to the angle of the Like the oropharyngeal airway, the nasopharyngeal air- jaw. The second is to measure the airway from the corner of way must be measured before placement to assure good sizing. the mouth to the inferior tip of the ipsilateral earlobe. Either The most common method for measuring the nasopharyngeal method is appropriate. airway is to place the airway against the face, measuring from An airway that is too small will not displace the tongue the nare to the ipsilateral inferior tip of the earlobe. Unlike the and jaw anteriorly and is at risk of being lost in the airway. An oral airway, the nasal airway should be lubricated before use. oral airway that is too large will tend to rise out of the mouth In addition, pretreatment of the nare with an inhaled vaso- and during ventilation, may actually displace the tongue pos- constrictor (e.g., neosynephrine) and topical anesthetic (e.g., teriorly. Therefore, it is important to only use an oral airway spray or viscous lidocaine) before placement may improve if the appropriate size is available. patient tolerance and decrease bleeding. It is important to note that the oral airway may stimulate a gag refl ex and should not be used in patients with an intact Bag-Mask Assembly gag refl ex.13,14 If an oral airway is to be used, suction must The bag-mask assembly is the most commonly used device be immediately available in the event that the patient vomits for providing assisted ventilation. In the operating room, during placement. anesthesiologists use high-fl ow respiratory gasses that con- While the oropharyngeal airway is made of hard plas- tinuously fl ow through a bag to a mask and that are checked tic, the nasopharyngeal airway is made of soft silicone with a by a valve which the anesthesiologist controls; hence the beveled tip (Figure 22-5). The nasopharyngeal airway is use- name bag-valve-mask. ful in patients with an altered mental status but with an intact In the prehospital environment, self-infl ating bags with gag refl ex. a reservoir, or bag-mask assembly, are the most commonly Non-Intubating Airway Management 399 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. cuff style mask is the most commonly used. These various mask types can also be attached to the ventilation devices discussed later. Barrier Devices and Pocket Masks Although mouth-to-mouth ventilation is still taught in CPR, there should be no need for an on-duty Paramedic to per- form this skill. If standard ventilation devices are not avail- able to the prehospital provider during a response, he should consider carrying a disposable face shield barrier device Figure 22-6 Bag-mask assembly. (Figure 22-7). Although not recommended by the American Heart Association except to the lay public, they are probably better than no barrier device at all. A second device that is used devices (Figure 22-6). The distal adapter of these bag- available is the pocket mask. mask assemblies is designed to attach to a mask or to the The pocket mask is a face-mask device that is powered 15 mm adapter of an endotracheal tube or an alternative air- by the lungs (Figure 22-8). Although devices without an oxy- way device. They are available in adult and pediatric sizes. gen inlet port are available, they should not be used in the There are common features to all of the devices. emergency medical environment. Rather, a device with an Every bag-mask assembly has a method of attachment to oxygen inlet port should be used to provide enrichment to the an oxygen source. This tubing runs into a self-infl ating bag. 17% oxygen in an exhaled breath. The masks are equipped Adult bags may be as large as 1,600 cc. Attached to the bag with a disposable one-way valve. is a reservoir that serves the same function as the reservoir on There are a number of limitations to the use of the pocket the nonrebreather mask. The reservoir allows oxygen fl ows mask in the prehospital environment. Although they have been far above the fl ow from the regulator without entering room demonstrated to be superior to one-person bag-mask assembly air. The oxygen passes through a one-way valve and out the distal port. On exhalation, expired gasses escape distal to the one-way valve, preventing remixing in the bag. Although bag-mask assemblies are commonly used, they are not nearly as easy to use as they appear. As early as 1983, it was clearly demonstrated that use of the pocket mask proved to be far superior to the one-person bag-mask assembly tech- nique. Although rescuers are able to deliver appropriate tidal volumes of 6 to 7 mL/kg, the excessively large volumes of adult bag-mask assembly ventilators are associated with over ventila- tion. In addition, technique can vary greatly, and overly rapid high-pressure ventilation typically results in gastric infl ation. Excellent bag-valve-mask technique is therefore an important skill for the Paramedic to master.21–23 Preparation of the bag-mask assembly is simple. The device is removed from its packaging and attached to an oxygen source fl owing at least 15 LPM. If a bag reservoir Figure 22-7 Barrier device. is attached, it should infl ate. If the reservoir is made of col- lapsible tubing, it should be extended to its fullest length. The Paramedic attaches the mask to the ventilation adaptor. Some pediatric BVMs include a pressure relief pop-off valve between the bag and the mask. This pop-off valve should be closed to ensure adequate ventilation to the pediatric patient. Although most bag-mask assemblies are packaged with a single mask, there are a number of different mask sizes and styles. Mask sizes vary from premature infant to large adult. Mask styles include masks with air-fi lled cuffs; masks with- out cuffs; soft, circular style masks; and gel-fi lled masks. The appropriate-sized mask is the mask that seats from the bridge of the nose to the chin. Specifi c applications for different mask types will be dis- cussed in the following text. In general, however, the air-fi lled Figure 22-8 Pocket mask. 400 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. ventilation in regard to delivering appropriate tidal volumes, while using oxygen only during the “inhalation” phase of their inherent design makes them undesirable to use. They ventilation. They reliably deliver 100% oxygen. In addition, require a high degree of activity and respiratory fi tness on the they can be used in patients who are awake to provide inter- part of a rescuer to provide extended ventilation. Placing one’s mittent ventilatory support. face so close to the patient’s face increases the risk of blood, There are some limitations to these devices. These vomit, and body fl uid exposure.24–28 Also, the position for use is devices may still cause gastric infl ation and barotrauma. awkward. Nonetheless, these devices can be a good alternative Without a trigger extender, two rescuers are required to effec- to one-rescuer bag-mask assembly ventilation until assistance tively use the devices. There are no studies that compare these arrives. devices to other ventilation devices. Nonetheless, they are The pocket mask is prepared by pushing the dome of still in use and may provide the Paramedic with a ventilatory the mask out of the cuff if the mask is stored in a collapsed alternative. position. The oxygen port is attached to an oxygen source at Preparation of a manually triggered fl ow-restricted, 15 LPM. An alternative is to place a nasal cannula on the oxygen-powered ventilator is relatively straightforward. The rescuer at a high (10 LPM) fl ow. A one-way valve should be device must be attached to a 50 PSI oxygen source. A mask is attached to the inhalation/exhalation port. attached to the outlet port. Care must be taken to assure that the one-way valve unit is disassembled and cleaned after each use or that an in-line fi lter is used. Manually Triggered Flow-Restricted, Oxygen-Powered Ventilation Devices Automatic Transport Ventilators Manually triggered oxygen-powered ventilation devices have Automatic transport ventilators (ATV), mechanical devices a long history in EMS. However, older models were neither that deliver a specifi ed volume of respiratory gas, have been fl ow nor pressure restricted and were prone to producing gas- used in the prehospital environment in Europe since the late tric infl ation and barotrauma.29,30 The more recent versions of 1970s. Although not used nearly as extensively in the United these devices are fl ow restricted and the valve pressures are States, these devices are gaining increasing acceptance.31,32 limited to less than 30 cm water, the commonly accepted car- There are now several models of automatic transport ventilators diac sphincter opening pressure (Figure 22-9). that are designed specifi cally for use in the prehospital environ- This pressure restriction limits gastric infl ation, but does ment (Figure 22-10). Although most studies on these devices not eliminate it. Most of these devices can be both manually have focused on their use in the intubated patient, there has been triggered or triggered in the same fashion as a demand valve some research into using automatic transport ventilators with a device. mask for face-mask ventilation. Flow-restricted oxygen-powered ventilation devices have The automatic transport ventilator has demonstrated a the advantage of delivering high oxygen fl ow rates (40 LPM) number of advantages compared to other methods of non- intubated ventilation. The ATV allows one rescuer to deliver consistent tidal volumes at a set rate. The automatic feature allows one rescuer to use both hands to seal the face mask. ATVs have demonstrated better lung infl ation and less gas- tric infl ation than bag-mask assemblies or oxygen-powered, manual-triggered devices. In addition, they consume signifi - cantly less oxygen than other devices. There are disadvantages to the ventilators. They require an oxygen source to function and some even require an electrical source. They may be inappropriate for small Figure 22-9 Flow-restricted, oxygen-powered ventilation device. Figure 22-10 Automatic transport ventilator. Non-Intubating Airway Management 401 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any |
suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. (< 30 kg) patients. A bag-mask assembly must always be avail- able for backup. Although ventilators will vary widely by manufacturer, there are common features. All will have an oxygen input source that must usually be attached to a 50 PSI oxygen source. All will have a means of setting rate and volume. There is usually a method for providing various rates at different vol- umes and vice versa. Most will have a disposable circuit that attaches to the oxygen output, usually with an in-line fi lter and distal one-way valve. The distal end of the ventilation circuit will have a standard 15/22 mm coupling. Beyond these features, however, the devices will vary Figure 22-11 Portable suction unit. widely. Most have a peak inspiratory pressure limit and an audible warning when that pressure is exceeded. Although most transport ventilators are volume cycled (deliver a spe- convert an unmanageable airway into an easily managed cifi c volume regardless of pressure) or time cycled (deliver airway through the removal of vomit, blood, and some a set fl ow rate for a specifi c time period), there are pressure foreign bodies. Prehospital suction units include porta- cycled (deliver to a specifi c pressure for a specifi c time) ATVs ble devices (Figure 22-11) and fi xed, wall-mounted units available. More sophisticated models will allow positive end (Figure 22-12). Having these pieces of equipment imme- expiratory pressure (PEEP) during ventilation as well as diately available d uring airway management is absolutely continuous positive airway pressure (CPAP). Finally, some critical. devices may have a demand valve mechanism that allows There are a number of different types of portable suc- patients to inspire on their own. These concepts in ventilation tion units. The least expensive are the hand-powered devices. will be discussed in more detail in Chapter 25. Using the Paramedic’s grip strength, these devices provide a lightweight, portable, and inexpensive alternative to portable Suction suction. Unfortunately, they tend to have a low volume and are One of the most critically important pieces of airway man- limited by the rescuer’s hand strength and fatigue. Oxygen- agement equipment is the suction unit. This device may powered suction units are another lightweight alternative. Figure 22-12 Wall-mounted suction unit. 402 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. They also have limited suction power and use large amounts All suction devices should be routinely checked for func- of oxygen. tion. Generally, suction tubing and sometimes even a rigid To provide more suction power, battery-powered suction catheter are left attached to the suction device. If these are not units are often used. These devices, although more expensive, attached, they should be stored on the device. Once the device provide very strong suction and can suction large volumes. has been turned on, the suction tubing should be kinked to Their greatest limitation is that, in actual use, the batteries test that adequate suction is generated. often loose their charge and integrity, resulting in loss of suction power after very short periods of suctioning. Some manufacturers have made devices that use interchangeable defi brillator batteries. The strongest suction devices are the wall-mounted, vacuum-powered units. These units provide adjustable vacuum Street Smart strength and completely disposable components. Although they provide the best suction, they are non-portable and can Placing the patient in left lateral decubitus position only be used in the ambulance. Nonetheless, they provide (side lying or recovery position) allows for drainage of excellent suction. secretions by gravity. Consider placing the patient in Regardless of type, the suction unit should be able to generate an airfl ow at the tip of 40 LPM and a vacuum of this position when the patient’s condition allows and 300 mmHg when the tubing is kinked closed. In addition, suctioning may be delayed for any reason. the collecting chambers and all parts of the device at high risk for contamination should either be disposable or easily disinfected. In addition to the suction unit, the Paramedic will need suction tubing and suction catheters. The suction tubing should Opening the Airway be thick walled and non-collapsible. The tubing should be Once the Paramedic has prepared his equipment, the next large diameter, capable of handling large and highly viscous step is to open the airway and provide positive pressure ven- substances. In addition to the tubing, a selection of suction tilation. Using basic maneuvers is often the most important catheters will be needed including rigid and soft catheters. intervention a Paramedic can perform, particularly for the The rigid pharyngeal suction catheters are known as pediatric patient in respiratory distress or arrest but not yet Yankauer or tonsil tip catheters. They are designed to suc- in cardiac arrest. tion to the posterior pharynx and can handle large volumes As was discussed in Chapter 20, the most common ana- of fl uid rapidly.33 Many of these catheters have a small tomical cause of airway obstruction is the epiglottis along side port that allows the Paramedic to apply suction only with the soft palate.9 Since uvular manipulation is less impor- when desired. These devices are available in multiple sizes tant if the patient has a patent oral cavity and oropharynx, although they are most commonly grouped into the adult or a irway manipulation techniques are oriented toward establish- pediatric size. ing a patent hypopharynx. Although traditional teaching has Multiple sizes of soft, sterile suction catheters should focused on the tongue as the most common source of airway also be available to the Paramedic. These catheters come obstruction, head-tilt, chin-lift, modifi ed jaw thrust, and jaw- in a number of sizes and are fl exible, allowing them to be thrust techniques apply equally well to epiglottis management. passed through the mouth, the nose, an endotracheal tube, This is due to the ligaments and muscles that interconnect the or a tracheostomy tube. These tubes, like the rigid pharyn- epiglottis, the hyoid, the mandible, and the tongue. geal suction tips, can become easily occluded with particu- For most non-trauma patients in respiratory arrest, the late matter. Therefore, it is important that water be available technique of choice for opening the airway is the head-tilt, chin to fl ush the catheters. These catheters are often sized using lift. The maneuver extends the neck over the atlanto-occipital the French catheter scale, which provides a measure of the joint (the joint between the skull and the fi rst vertebrae). In outside diameter of the catheter. The smaller the number addition, the chin lift displaces the mandible anteriorly. This on the French scale, the smaller the outer diameter of the in turn pulls the hyoid anteriorly and via the hyoepiglottic catheter. ligament, the epiglottis. There are side-port suction devices designed specifi cally The technique is performed by placing the palm of one to suction through endotracheal tubes. These devices fea- hand on the forehead and either actively hooking the mandible ture a “T” or “Y” piece that allows the endotracheal tube to with the fi ngers and lifting or griping the tip of the mentum be attached to the ventilator circuit (or bag-mask assembly) (chin) between two fi ngers and pulling forward. A common without interrupting the gas fl ow. There is either an integrated error is to simply place the fi ngers on the mandible and push soft suction catheter or a self-sealing port through which a upward. This action closes the mouth without moving the soft catheter can be placed. These devices greatly facilitate hyoid anteriorly. The jaw must be actively displaced in an endotracheal tube suctioning. anterior and caudad direction. In addition, minimal pressure Non-Intubating Airway Management 403 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. should be applied to the soft tissue under the mandible as this placed in the mouth and the fi ngers under the chin. The jaw may push the hyoid posteriorly. is then pulled forward. Although this technique effectively For the patient with suspected cervical spine injury, the opens the airway, it severely compromises the ability to head-tilt, chin lift can compromise the cerviocal spine; partic- ventilate the patient with a face-mask technique. In addition, ularly in high cervical injuries involving the fi rst and second it requires the Paramedic to keep his thumb in the patient’s cervical vertebrae.34–37 Therefore, an alternative technique— mouth. This technique puts the Paramedic at risk for losing the modifi ed jaw thrust—must be used. This technique dis- a digit, something that should be avoided if at all possible. places the jaw anteriorly, pulling the hyoid and epiglottis To avoid having the patient bite the Paramedic, a large oral anteriorly as well. There is minimal cervical spine movement airway can be lodged sideways in between the molars to act if the jaw thrust is performed correctly. as a bite block. Even with the placement of an oral airway The modifi ed jaw thrust is usually performed from the top as a bite block, the tongue-jaw thrust is probably of limited of the patient’s head, although it can also be performed from an practical use in the prehospital environment because it limits inferior position if needed. From above the patient’s head, the ventilation. right and left hand are placed palm-in on the right and left side of the patient’s head. The thumbs are placed on the prominence Cricoid Pressure of the cheekbones and the fi ngers are placed along the ramus While opening the airway, the Paramedic should also con- and angle of the mandible. The fi ngers are then lifted anteriorly sider the benefi ts of cricoid pressure (Figure 22-13). This and caudally (toward the feet) while the thumbs push posteriorly. technique, referred to as Sellick’s maneuver, involves the These opposing actions open the mouth and lift the hyoid and identifying the cricoid ring and assigning an individual to epiglottis. If the technique is performed from below the head, gently apply approximately 10 pounds of pressure in a poste- the only difference in hand position is that the airway manager’s rior direction throughout airway management; from the onset right hand will be on the left side of the patient’s face and vice of ventilation until completion of intubation. Since the cri- versa. The jaw will essentially be pulled toward the rescuer, again coid is a complete ring, the pressure is transferred directly to opening the airway. the esophagus and helps to keep the esophagus closed.38–42 The modifi ed jaw thrust can be performed on any patient Cricoid pressure has long been considered to prevent pas- regardless of suspicion of C-spine injury. The hand position- sive regurgitation and limit active emesis when properly applied. ing allows the Paramedic to both open the airway and form a Additionally, cricoid pressure may decrease gastric infl ation dur- mask seal at the same time. A sustained modifi ed jaw thrust, ing positive pressure ventilation. It is a non-invasive technique however, can be very tiring and may require multiple rescuers and, as long as it is maintained continuously, can limit (although to switch in and out of the role. not eliminate) the risk of aspiration. A third technique, the tongue-jaw lift, can also be used Cricoid pressure is not without its limitations. Cricoid in limited circumstances. In this technique, the thumb is pressure can actually worsen the view of the vocal cords Figure 22-13 Cricoid pressure. 404 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, |
in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. during laryngoscopy.43 Even when properly applied, it does ventilation” for the patient in respiratory distress, not arrest, not completely eliminate the risk of aspiration. In addition, will be discussed later. The technique for providing ventila- in vigorous emesis, it can lead to esophageal rupture; there- tion will depend on the device used. fore cricoid pressure should be released if the patient actively vomits. Excessive posterior pressure can also compromise an unstable cervical spine injury, as the cricoid cartilage is The Mask/Face Interface juxtapositioned across from the fourth cervical vertebrae. The most important task of bag-valve-mask ventilation is to Excessive posterior pressure may also cause laryngeal trauma form an effective mask seal while maintaining an open air- if excessive force is applied. In pediatric patients, excessive way. Recalling that the mouth is kept open by caudad (foot- force can actually occlude the trachea because the cartilage ward) displacement of the mandible while the hypopharynx rings that maintain an open trachea have not fully formed in is kept open by the anterior displacement of the hyoid, any the younger pediatric patient.44 Finally, cricoids pressure must technique to form a mask seal must also displace the man- be vigilantly maintained throughout airway management dible correctly. Although much is made of the pressure on the until large volume, high-capacity suction is available and, mask in forming the seal, the most important component of preferably, the patient is endotracheally intubated. Premature a good mask seal is to actually bring the face anteriorly and release of cricoid pressure can result in copious and explosive into the mask. emesis. The best mask seal which maintains an open airway is Another signifi cant limitation to cricoid pressure is that, made with light downward pressure on the mask and more unfortunately, pressure is often not on the cricoid at all but forceful upward displacement of the mandible. The lower face is applied to the thyroid cartilage. As will be discussed next, is, in essence, “gathered” into the mask to form the seal. This landmark recognition and appropriate identifi cation of the cri- method of forming a mask seal maintains an open mouth, coid ring can be diffi cult.45 Often, pressure will be applied to an anterior displacement of the hyoid and epiglottis, and a the most prominent structure, usually the thyroid cartilage. tight junction between the mask and the facial tissue. This There are a number of untoward consequences of thyroid is in contrast to strong posterior pressure on the mask that cartilage pressure. First, the thyroid cartilage is an incomplete may close the mouth and will push the hyoid and epiglottis structure, so posterior pressure will not achieve esophageal posteriorly. occlusion. Second, pressure on the thyroid cartilage may The fundamental method of gripping the mandible and cause the opening of the larynx to tip anteriorly, making the mask is the “C” and “E” technique. The major difference endotracheal intubation more diffi cult. Third, excessive pres- between one-rescuer bag-mask assembly ventilation and other sure may cause laryngeal injury. Therefore, proper location of techniques (two-rescuer and three-rescuer bag-mask assem- the cricoid ring is critical for effective and safe performance bly, ATV, etc.) is that with one-rescuer bag-mask assembly of this skill. ventilation, only one hand is used to make the seal while with To overcome the challenges of locating the cricoid ring, the other techniques, one of the rescuers has both hands free the Paramedic should be familiar with the anatomy of the for the procedure.47–50 region, as described in Chapter 20. Although there are a num- The mask is gripped with the thumb at the nasal side of the ber of methods for locating the cricoid ring, the easiest begins mask and the index fi nger on the chin side of the mask. These with locating the prominence of the thyroid cartilage. This two fi ngers are curved to make a “C” shape. The middle, ring, is usually the most prominent anterior midline structure of and little fi nger are extended along the mandible with the little the neck. Once this landmark is identifi ed, the index fi nger fi nger pushing forward on the angle of the mandible. These should be placed on it and then moved inferiorly along the three fi ngers are spread to make an “E” shape. Using the “C” midline. and “E” technique, the Paramedic should be able to maintain a The next landmark is the cricothyroid membrane, the liga- suffi cient mask seal while bringing the lower face up into the mentous band between the thyroid cartilage and the cricoid ring. mask. If a two-handed technique is used, both hands make mir- The inferior border of the thyroid cartilage should be easily iden- ror image “C’s” and “E’s.” tifi ed and a soft depression can be felt. The inferior border of this Certain facial characteristics will also make forming a depression is a solid structure, the cricoid ring. Once the cricoid mask seal more diffi cult. These include a small jaw (microg- ring is identifi ed, the thumb and index fi nger should be placed nathia), a large tongue (macroglossia), facial hair and trauma, on it and pressure applied posteriorly.46 This pressure should be no teeth (edentulous), and patients with minimal subcutane- maintained until the patient is intubated or, at a minimum, high- ous fat.9 Micrognathia and macroglossia require vigilance capacity suction is available. to anterior jaw displacement and maintaining the most open mouth possible. A better seal may be obtained on patients with facial hair if water-based lubricant is applied to the mask and Face-Mask Ventilation the facial hair before ventilation. Patients with facial trauma Once the airway is opened, the patient may begin to breathe present a signifi cant challenge. spontaneously. If this is not the case, the Paramedic must The best technique is to focus on gathering the face into begin ventilation of the apneic patient. The skill of “assisted the mask and suctioning frequently. Specifi c injuries such Non-Intubating Airway Management 405 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. as penetrating objects or puncture wounds to the face may This is important because the pressure is related to the fl ow require stabilization and sealing of the wound with petroleum rate of the gas. A higher pressure is needed to deliver a gauze to prevent air leakage. If a patient has dentures, these large volume in a short time period. On the other hand, less should be left in place to facilitate the mask seal.51 Premature pressure is needed if that volume is delivered over a removal of the dentures will result in a poor mask seal. Patients long time period. Since high airway pressure is the main with thin subcutaneous tissue or excessive subcutaneous fat cause for gastric infl ation and barotrauma, it is important will benefi t from the use of a softer mask or one into which to maintain as low an airway pressure as possible during air can be added and removed. ventilation. The gas fl ow/pressure/volume relationships are practi- Ventilation Volume cal because oxygenated tidal volume delivery is probably the and Airway Pressure most important goal of bag-valve-mask ventilation. Since Once the Paramedic has opened and is maintaining the airway the same tidal volume (and same amount of oxygen) can be and has achieved a good mask seal, the next action is to ven- delivered at lower pressures if the inspiratory phase is longer, tilate the patient. When a patient is receiving ventilation from the Paramedic should focus on providing slower, longer dura- a face mask, ventilatory gasses have the opportunity to enter tion, and lower pressure ventilations. In fact, ventilation that either the trachea or esophagus. Although the trachea usually delivers less oxygen to the stomach and more to the lungs is offers the path of least resistance, the lungs have a limited better ventilation. volume beyond which they will not expand. Therefore, any The practical consequences are that while the ventila- excess volume will end up in the stomach. tory rate (12 to 16 breaths per minute for an adult, 20 breaths The main determinant of esophageal resistance is per minute for a pediatric patient) remains the same, the the lower esophageal, or cardiac sphincter, opening pres- v entilations themselves are given over a longer time period. sure. Not an actual valve, the lower esophageal sphincter The inspiratory phase of ventilation should occur over two (LES) is a functional portion of the esophagus where the seconds and the expiratory phase should take about the same walls of the esophagus contract inwardly, forming a physi- amount of time. If a bag-mask assembly device is being used, cal barrier to the refl ux of stomach contents up the esopha- the Paramedic should use a mental trigger like “squeeze, gus. Although probably somewhat lower in the prehospital squeeze, release, release” while performing ventilations. patient, the accepted value for normal LES opening pressure Bag-valve-mask ventilators are available with built-in in healthy individuals is 30 cm water. Upper airway pres- and aftermarket add-on manometers that allow the Paramedic sures in excess of 30 cm water will cause the LES to open. to know exactly how much airway pressure is being gener- Most likely, LES opening occurs over a range of pressures, ated. In addition, most mechanical ventilation devices (man- with lower pressures causing small leaks and high pressures ually triggered fl ow-restricted, oxygen-powered ventilators causing larger leaks. and automatic transport ventilators) have built-in pressure In addition, there are a number of factors which relax relief valves. Whenever possible, a manometer should be the LES. Alcohol, mint, chocolate, and caffeine will all relax used to minimize the risks of overpressurization. If a manom- the LES. In addition, LES opening pressure drops in cardiac eter is not available, however, delivering the ventilations as arrest to almost zero within a few minutes. If any of these previously described should provide the minimum pressures factors are present, the LES will open at lower pressures, possible. increasing the risk of gastric distention and vomiting. These are two consequences which can be minimized with thought- Bag-Mask Ventilation ful face-mask ventilation. The most commonly used device, as discussed previously, is The tidal volume in a healthy individual is somewhere the bag-mask assembly. The greatest limitation to this device between 5 to 7 cc/kg of ideal body weight.52–54 At a respi- is that it is diffi cult for a single rescuer to provide effective ratory rate of 12, this results in a minute ventilation of tidal volumes. The diffi culty arises from the need to simul- 4 to 5 LPM. For an acutely ill patient (e.g., asthma), the taneously form a mask seal, maintain an open airway, and minute ventilation demands may reach almost 20 LPM. squeeze the bag. In general, however, the ventilation demands of most pre- Effectively performing all three techniques single- hospital patients do not exceed 7 cc/kg/breath. Therefore, handedly is almost impossible. Therefore, although the Paramedic should attempt to deliver a tidal volume of one-rescuer bag-mask ventilation is commonly performed, 6 to 8 cc/kg ideal body weight/breath. two-rescuer ventilation is much preferred. In addition, there The volume delivered can be thought of as depend- are three rescuer techniques that are also used, as will be ing on two variables: gas fl ow rate and duration of fl ow. discussed in the following text. That is, the same volume (i.e., 800 cc) can be delivered if One key to proper performance of bag-valve-mask venti- the gas fl ow rate is 800 cc/second and the patient is venti- lation is maintaining a proper mask seal (Figure 22-14). The lated for one second as is |
delivered if the gas fl ow rate is Paramedic’s thumb and pointer fi nger form the letter “C” over 400 cc/second and the patient is ventilated over two seconds. the edge of the mask, applying pressure to hold the mask to the 406 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Figure 22-14 Proper hand positioning to maintain bag-valve-mask seal. face. The other three fi ngers form the letter “E” fi rmly holding the delivered volume, then these techniques should not be the mandible, allowing the provider to simultaneously provide used. In addition, since many larger muscle groups are being either a jaw thrust or chin lift depending on the need to limit used, these techniques can be very tiring. These techniques cervical spine movement. are mentioned only because they have been described and Estimating the volume delivered can also be diffi cult. used. However, they have not been validated. The Paramedic The Paramedic should take advantage of any opportunities must decide what technique is safest and most effective for to practice this skill when volume measuring is available. the patient. Several simple rules can assist the Paramedic in estimating Although the least recommended of the bag-mask assem- the ventilation volume. bly techniques, single-rescuer bag-mask assembly ventilation First, the volume should be suffi cient to cause chest is probably the most common prehospital method of ventila- rise but not so much that the chest stops rising. The breath tion. There are several key points to remember in perform- should enter with little resistance and abdominal disten- ing single-rescuer bag-mask assembly ventilation. The fi rst tion should not be seen. There should, in fact, be almost no is that maintaining an open airway while establishing a good abdominal movement. In addition, the Paramedic should mask seal with one hand is diffi cult and, in some patients, know the volume of the bag on the bag-mask assembly. The impossible. The Paramedic should recognize when a patient average adult bag is 1,600 mL. Therefore, for a 70 kg male, cannot be ventilated without a second rescuer and immedi- approximately one third of the volume of that bag should ately call for assistance. The second key to performing good be delivered. one-rescuer bag-mask assembly ventilation is to be able to For Paramedics with small hands, there are techniques provide appropriate one-handed tidal volumes. which may be employed as an alternative to squeezing the The two-rescuer technique of bag-mask assembly venti- bag with two hands. Although no research has ever been lation (Figure 22-15) is a much more effective method of pro- performed to demonstrate the safety and effi cacy of these viding ventilatory support. The major difference between this techniques, there are anecdotal stories of effective ven- and one-rescuer ventilation is that each rescuer can now focus tilations being performed with their use. In the fi rst tech- on a specifi c component of the procedure. The Paramedic nique, the bag is compressed between the rescuer’s hand responsible for opening the airway and forming the mask seal or forearm and a solid object, such as the rescuer’s leg. In can use both hands to do this while the Paramedic responsible the second technique, the rescuer uses both hands to open for ventilation is better able to control the ventilatory volume the airway and form the mask seal while the bag mask is and rate. The same techniques and volumes as mentioned squeezed between the thighs. The major limitation of these for one-rescuer ventilation apply to two-rescuer ventilation. techniques is the possibility of poor control of the delivered This is the recommended technique for performing bag-mask volume. If the Paramedic is unable to effectively estimate assembly ventilation. Non-Intubating Airway Management 407 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Figure 22-15 Two-rescuer bag-mask assembly ventilation. There may be times when mask seal is diffi cult but airway to be maintained open more easily. The key to pre- additional rescuers are available. There are two forms of venting hyperventilation is for the Paramedic to take a slow three-rescuer bag-mask assembly ventilation that can be deep breath during the patient’s expiratory phase and then to performed. deliver the ventilation slowly over two seconds.55,56 In the fi rst of the two techniques, the third rescuer assists in making a mask seal. Once the fi rst two rescuers are in posi- Manually Triggered Flow-Restricted, tion, the third rescuer applies posterior pressure to the mask. Oxygen-Powered Ventilation Devices Although there may be some merit to this technique if the mask seal is particularly diffi cult to obtain, it has a number These devices offer a manual alternative for one-rescuer of limitations. ventilation. The mask seal is made as described previously. As was discussed previously, the most effective mask If the ventilation device has a well-designed trigger, the seal is made by gathering the patient’s face anteriorly into mask seal can be made with two hands and the device still the mask, not by pushing the mask posteriorly. The poste- triggered without having to release the seal. If the trigger rior pressure increases the risk of occluding the airway. In is poorly placed, however, it may be necessary to perform addition, having three people this close to the head makes the a one-handed seal while the other hand triggers the device. airway very “crowded” and moving the patient or performing Otherwise, a two-rescuer approach may be needed. This sec- other techniques may become impossible. ond technique, unfortunately, negates most of the benefi ts The second technique for three-rescuer bag-mask assem- that manually triggered fl ow-restricted, oxygen-powered ven- bly involves having the third rescuer apply posterior cricoid tilation devices offer over single-rescuer bag-mask assembly pressure, as discussed previously. This technique offers the techniques. advantage of having an extra hand available (the rescuer’s Since the devices are manually triggered, it is impor- hand not applying cricoid pressure) if needed to assist the two tant that the Paramedic provide no more than two seconds of primary Paramedics without overcrowding the area around ventilation at a time. Although the devices should have inte- the patient’s face. In addition, the benefi ts of cricoid pressure grated overpressurization relief valves, a prolonged inspira- are also obtained. tory phase without an expiratory phase may result in gastric infl ation and the potential for barotrauma. Pocket Mask Ventilation Using the pocket mask requires only two skills: forming a Automatic Transport Ventilators mask seal and not hyperventilating. The pocket mask is The automatic transport ventilator is a relatively simple tool sealed to the face in the same manner as other masks. The for face-mask ventilation. As was discussed previously, the Paramedic can use a two-handed technique to make the ventilator is set at an appropriate rate and volume for the mask seal, improving the quality of the seal and allowing the patient. The ventilator circuit is then attached to the mask 408 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Figure 22-16 Assisting ventilations with an automatic transport ventilator. and the mask seal obtained with a two-hand technique Patient Assessment (Figure 22-16). The ventilator will automatically cycle at for the Ventilated Patient the preset rate, freeing the Paramedic to focus solely on It is important for the Paramedic to assess all patients maintaining the mask seal and keeping the airway pat- whom she believes are being adequately ventilated. The ent. Shortly after ventilation is initiated, it is important to most important assessments are observation, auscultation, assess that the proper rate and volume have been selected. and physiologic monitoring. The most important task to This is done through observation of the chest rise and complete immediately is to observe the patient. Chest rise fall. In addition, all ventilators should have an overpres- and fall should be noted. The abdomen should be observed surization relief valve and alarm. If the alarm sounds, it is for signs of gastric infl ation. In addition, unless the patient important to immediately reduce the volume and check is in cardiac arrest, the signs of respiratory failure (pal- the rate to assure that “breath stacking” is not occurring. lor, cyanosis, and diaphoresis) should begin to improve. Breath stacking occurs when insuffi cient time is allowed for Immediate and ongoing observations of the patient and exhalation. of the effectiveness of ventilation will provide early warning of ventilatory failure. Continuing Ventilatory Care Once a general observation is complete, the Paramedic If the Paramedic is able to successfully ventilate the patient, should auscultate lung sounds. Auscultation can give some there are some immediate postventilation activities that must idea of the adequacy of ventilation (e.g., are lung sounds be performed. These include assessing the patient, inserting heard over the lung bases?). In addition, diagnostic clues an oropharyngeal (if tolerated) or nasopharyngeal airway, and may be discovered including asymmetric lung sounds, preparing the patient for transport. Each of these activities adventitious lung sounds (wheezes, crackles, and rhonchi), is important to assure that adequate ongoing care is being or absent lung sounds. Auscultation over the epigastrium provided. may also give the Paramedic a sense of how much gastric infl ation is occurring. In addition, a complete reassessment of airway, breathing, and circulation, including lung fi eld and epigastric auscultation, should be performed anytime Street Smart a patient’s status changes. After observation and auscultation, the patient should have physiologic signs measured and monitored. These The “look, listen, and feel” step of CPR is important include pulse, blood pressure, EKG, and pulse oximetry. for any patient who is being assisted in ventilation. The pulse oximetry probe should be applied early. A good pulse oximetry signal at a fi nger or earlobe indicates a blood Non-Intubating Airway Management 409 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. pressure suffi cient to produce at least peripheral perfusion pressure and pulse rate should then be measured manually. (Figure 22-17). An EKG (rhythm strip) should also be obtained to assess for arrhythmias. These parameters should be continuously monitored to assure that they remain stable or improve. Any Professional Paramedic deterioration (tachycardia, bradycardia, hyper- or hypoten- sion, or hypoxia) should trigger an immediate search for a cause. The professional Paramedic knows that normal After assessment, the patient should be prepared for pulmonary respiration relies on negative thoracic transport. Generally speaking, these patients are most easily pressure. This negative pressure is assistive in allowing transported on a long spine board. Care must be taken, par- ticularly for pediatric patients, to assure that the positioning blood return to the heart. By taking over ventilation, on the board does not cause the airway to obstruct. Unlike the physiology is changed from negative pressure to the intubated patient (discussed in Chapter 23), placement positive pressure. The patient may experience signs of a cervical collar for the non-trauma patient is not recom- of diminished cardiac output. This situation may mended as |
it will make maintaining a patent airway and mask seal more diffi cult. be exacerbated by a ventilation rate that exceeds the suggested rate for age. Gastric Distention Gastric infl ation and subsequent vomiting and aspiration are signifi cant risks associated with face-mask ventilation.57–59 Although proper ventilation technique will minimize the risk Street Smart of gastric infl ation, the risk cannot be eliminated. Therefore, the Paramedic must monitor for increasing abdominal girth, vomiting, and diffi culty performing ven- Continuously monitored pulse oximetry allows the tilation as signs of gastric infl ation. If gastric infl ation is Paramedic to monitor oxygenation saturation during detected, several interventions can be performed to minimize procedures such as suctioning and intubation. When its impact. the saturation begins to drop, stop the procedure and At the fi rst sign of gastric infl ation, the airway manager should reassess the ventilation rate, volume, and airway pres- ventilate/oxygenate the patient. sures. These should be corrected if needed. In addition, suc- tion should be prepared and made immediately available. If signifi cant gastric infl ation has occurred and is interfering In addition, the pulse oximetry will give a preliminary with ventilation, it must be corrected by placing either a naso- pulse rate and the hemoglobin oxygen saturation. The blood gastric or orogastric tube and attaching it to suction. Normal Poor Figure 22-17 Normal and abnormal pulse oximetry waveform. A good waveform indicates adequate perfusion to produce an accurate numerical value. 410 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. one of three ways. For all three methods, the mouth must be Street Smart opened using either a chin-lift technique or a crossed fi nger technique in which the thumb and index fi nger “cross” each other and push the teeth in opposite directions. Any visible A nasogastric tube is less likely to initiate a gag refl ex foreign bodies should be removed. than an orogastric tube and is a better choice for the In the fi rst method, the tongue is controlled with a tongue conscious, responsive patient. depressor or by the Paramedic using a jaw-thrust technique. The oral airway is inserted with the curvature in the same direction as the curvature of the airway and the tip of the oral airway toward the glottis. The oral airway is advanced until Failed Ventilation the fl ange rests on the lips and the positioning is reassessed to assure that the tongue has not been pushed posteriorly. This If the fi rst attempt at ventilation is unsuccessful, the Paramedic method is recommended for pediatric patients. must make an assessment of the causes of failure. This The second and third methods are similar in that neither assessment should reevaluate the provider, the patient, and requires a tongue depressor and in both the tip of the airway is the equipment being used. Once this assessment is complete, initially not pointing toward the glottis. Instead, the distal tip further consideration of additional interventions and equip- of the airway is either pointed toward the cheek (method 2) or ment must be made. toward the palate (method 3). The oral airway is advanced to Reevaluation approximately half its length and then rotated so that the distal tip points toward the glottis. The fl ange is again advanced to the In reevaluating the provider, the Paramedic must examine his lips and its position is confi rmed. own technique. Single-person bag-mask assembly ventila- Placement of the nasopharyngeal airway requires the tion, limited in the best of circumstances, may simply not be Paramedic to assess which nostril is more likely to accom- possible and another rescuer may be needed. All providers, modate the airway. Evidence of nasal fracture or septal devia- however, should have suffi cient skill and training to provide tion should be noted. Once the nare has been chosen, the tip two-person bag-mask assembly ventilation. of the nose should be pushed superiorly so that the nares are The patient should also be reassessed. The most com- closer to parallel with the face. With the bevel facing toward mon cause of ventilatory failure is that the airway was not the septum, the nasopharyngeal airway is inserted parallel to appropriately opened. Therefore, the airway opening tech- the fl oor of the nasal cavity. nique and the patient positioning should be evaluated. Ideally, Due to the design of nasal airways, different initial orien- the airway opening maneuver should be performed again.60 tation is required based on which nare is used. If the airway In addition, the patient should be reassessed to determine if is inserted in the right nare, the curvature of the nasal air- anatomic or pathologic features are making ventilation dif- way should be in the same direction as the curvature of the fi cult. Conditions which make forming a mask seal diffi cult nasopharynx. If the nasal airway is inserted into the left nare, were discussed earlier. The Paramedic must consider if any of however, the curvature is upside down. This is due to the way these conditions are present. the bevel is designed. Once the bevel is entirely within the left The Paramedic must then assess the equipment. side of the nasal cavity, the nasal airway is then rotated 180° Equipment failure is not uncommon and can occur at highly and the airway advanced. inopportune times. Masks may leak and oxygen sources may The airway is advanced until the fl ange rests against be empty. Mechanical ventilators may suffer part fatigue or the opening of the nare. If resistance is met, the nasal air- failure. If there is any suggestion of equipment malfunction, way should be gently rotated from side to side but should an alternative device should be considered and utilized. not be forced. The patient may gag and vomit; therefore, the Paramedic should be prepared to suction the patient if needed. Oropharyngeal and Nasophayngeal If the patient is gagging excessively or appears to be having Airway Placement diffi culty breathing, the Paramedic should remove the nasal Once the Paramedic has reassessed and repositioned the airway and replace it with a shorter one. patient, he must consider the use of ancillary techniques and equipment. The insertion of an oropharyngeal or nasopharyn- geal airway is therefore appropriate. Suctioning As discussed previously, oropharyngeal airways help to While reevaluating the airway, it may become evident that displace the tongue and, ultimately, the hyoid anteriorly. There vomit or fl uids in the airway need to be suctioned. The suc- are multiple methods for inserting oral airways. Personal pref- tion unit should have already been prepared for just such an erence, at least for the adult patient, is the best guide. eventuality. Although the fi nger sweep (discussed later) or The ultimate position of the oral airway is with the fl ange the use of the Magill forceps (discussed in Chapter 23) may resting at the lips and the curve of the oral airway matching be necessary to manage foreign bodies, blood and vomit can the curve of the oropharynx. The airway can be inserted in usually be handled with standard suctioning procedures. The Non-Intubating Airway Management 411 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. primary goal of suctioning is to minimize the risk of aspira- tion and to prevent it, if possible. All suctioning efforts must be directed toward that end. The rigid Yankauer or tonsil tip suction is the device of choice for suctioning the oral cavity and the oropharynx. If possible, the patient should be pre- and postoxygenated; how- ever, this may not be possible if the patient is apneic and the Paramedic has not been able to ventilate the patient. The tip should be placed in the mouth and advanced to the posterior oropharynx. At no time should the distal end of the tip be com- pletely out of sight. Suction is applied as the tip is withdrawn. The Paramedic should avoid applying suction to mucous mem- branes or other attached structures. No more than 15 seconds of suction should be applied continuously in order to avoid hypox- ia.61 After suctioning, the airway should be reassessed and, if appropriate, the patient should be ventilated and oxygenated. If on reassessment there remains a signifi cant amount of material that interferes with ventilation, resuction the patient. Obstructed Airway Management If after the second ventilation attempt it is impossible to ven- tilate the patient, the patient should be assumed to have an Figure 22-18 Infant back blows. airway obstruction. There are a number of causes of airway obstruction including the epiglottis, the soft palate, foreign bodies, laryngospasm, laryngeal edema, and airway trauma. If proper airway opening techniques were applied, then the then the patient must be transported rapidly or turned over to a epiglottis and soft palate should have been addressed. On the caregiver capable of performing advanced airway management other hand, obstruction laryngospasm, laryngeal edema, and procedures. No further value is gained by delaying on-scene. signifi cant airway trauma cannot be dealt with at a basic air- way management level. Efforts must focus on ventilating as best as possible and transporting the patient rapidly. Foreign Assisted Ventilation body obstruction, however, can and should be addressed. Although most patients who receive face-mask ventilation If the patient is conscious and has evidence of complete in the prehospital environment are apneic, some breathing airway obstruction, then abdominal thrusts should be applied patients will benefi t from ventilatory support. These patients from behind. It is important, whenever possible, to treat an may be tachypneic or bradypneic. The most important char- airway obstruction while the patient is conscious.62–65 Once acteristic of these patients is that their ventilatory effort is a patient with an airway obstruction becomes unconscious, insuffi cient to meet their metabolic demands. mortality increases rapidly.66 Therefore, aggressive manage- Assisted ventilation is the process of augmenting the ment of the conscious patient with a possible airway obstruc- breaths a patient is taking to provide more effective respira- tion is mandatory. tions. The device most commonly used for this process is the If, however, the patient becomes unconscious or is found BVM. The key to this technique is that the Paramedic must unresponsive and has a foreign body airway obstruction, the time ventilation with the patient’s own inspiratory effort and techniques of abdominal thrusts described in the following assure a minimum minute ventilation. In the patient who is text should be used. very bradypneic, it may be necessary to provide additional For infants, back blows are the preferred method of clear- breaths between the assisted breaths to meet the minimum ing the airway (Figure 22-18). Otherwise, the sequence of minute ventilation. On the other hand, for a patient who is back blows, airway assessment, and attempts at ventilation tachypneic, it is not necessary to supplement every ventila- remain the same. tion. The goal of assisted ventilation is to provide patients The fi nger sweep is a technique of limited value in the with approximately 12 to 20 breaths/minute that meet the EMS environment. Suction and laryngoscopy perform the patient’s appropriate tidal volume (6 to 8 cc/kg). task of foreign body management much more effectively. If the patient remains responsive, it is important to explain Finger sweeps are probably most useful in the patient who is what will be done and why it is being done. For the patient vomiting more than the suction can handle. who is already hypoxic, the face mask may cause claustro- If the patient still cannot be ventilated after suctioning, phobia and a sense of suffocation. In addition, the patient repositioning, and obstructed airway skills have been applied, may feel |
some resistance to inhalation. In addition, use of 412 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. an anxiolytic such as diazepam or midazolam may make the CPAP is essentially a way of assuring that in all phases of patient more comfortable during assisted ventilation.67 the respiratory cycle the airway pressure is above zero (zero An appropriate-sized mask is selected and the Paramedic being the atmospheric pressure). During the normal respi- makes a one-handed mask seal. The other hand gently com- ratory cycle, the intrathoracic pressure becomes negative presses the bag and stops when the bag is slightly dimpled. during inspiration, zero at the end of inspiration, positive dur- The Paramedic waits until the patient begins to inhale before ing expiration, and zero again at the end of expiration. These squeezing the bag to provide a full ventilation. When the pressures are generated not by external forces but rather patient begins to exhale, the bag is released. This process through the musculature and bony structures of the chest of supplementing the patient’s own inspiration should occur cavity. The mechanism for producing negative pressure was 12 to 20 times/minute. discussed in Chapter 20. Positive pressure is generated by the The most diffi cult part of this skill is the timing of the elastic recoil of the chest wall. The alveoli are held open via ventilation. If the ventilation is delivered while the patient is surfactant and their indirect attachment to the chest wall. At exhaling, not only will it be ineffective but also high airway the zero pressure end of expiration, however, the alveoli can pressures, barotrauma, and gastric infl ation may occur. If the collapse, resulting in atelectasis. This is the issue that CPAP breath is delivered too early, the patient will feel suffocated attempts to address. and uncomfortable. Therefore, the timing of the assisted In the healthy adult, sighing is a refl ex mechanism that breath is critical. The Paramedic must be able to sense when opens collapsed areas of the lung. Grunting against a closed the patient is beginning to inspire and deliver the assisted glottis achieves the same end. These mechanisms become ventilation at that time. There are three ways in which the less effective during disease. For the patient with emphy- start of inspiration can be determined. The fi rst is to simply sema, the alveolar walls break down, decreasing effective observe the patient’s chest. When the chest begins to expand, oxygen exchange surface and increasing the risk of col- the patient is inspiring, and the breath should be delivered. lapse. Patients with congestive heart failure (CHF) are also Unfortunately, these patients will not usually tolerate being more susceptible to alveolar collapse. At the end of expi- laid fl at and the Paramedic will often stand behind the upright ration, the surfactant in these patients may be insuffi cient patient. Therefore, observation may be ineffective. to keep open the airways, allowing the alveoli to collapse The two other methods of determining the start of inspi- during exhalation. These patients may not then have the ration do not require direct patient observation. The fi rst ability to re-expand the collapsed alveoli, and so they have involves placing a fi nger on the bag-mask assembly and less gas exchange surface and become more hypoxic and mandibular soft tissues. When the patient begins to inspire, hypercarbic. the mouth will usually open slightly and the larynx will pull CPAP uses a combination of gas fl ow and resistance to superiorly. These movements can be palpated and recognized exhalation to increase the minimum airway pressure. High- as the time to initiate ventilation. The other method involves fl ow gas (oxygen mixed with room air) is fed into the mask dimpling the bag with the fi ngers before providing the ven- at 50 to 100 LPM. The mask is tightly sealed against the tilation. By applying a slight amount of pressure to the bag, patient’s face, only allowing exhaled gas to escape through the pressure within the mask can be monitored. When the bag an exhalation port and CPAP valve. The CPAP valve is a begins to compress easily, the patient has begun to inspire and special valve designed to open at a set pressure (typically the bag should be squeezed to deliver the appropriate tidal 5 to 15 cm water). If that pressure is not present, the valve volume. Although this technique requires some practice, it is will not open. a very effective method of determining when to ventilate. As respiratory gasses can only escape through the CPAP The patient should be continuously assessed during valve, gas will build up in the system, resulting in increased assisted ventilation. While the increased tidal volume and pressure. The whole connected system includes the CPAP adequate minute ventilation may cause the patient to improve, generator, the large volume tubing, the face mask, the patient’s the patient’s underlying disease process may cause him to airways, and the lungs. The pressure will eventually equalize decompensate. The Paramedic must be vigilant to assure that throughout the system. Since the gas fl ow is so high, the pres- the patient is receiving adequate ventilatory support. sure in the system quickly reaches the opening pressure of the CPAP valve. If the CPAP valve is set to open at 10 cm H O, 2 then the pressure throughout the entire system, including the Continuous Positive alveoli, will be at least 10 cm H O. This air pressure prevents 2 Airway Pressure alveoli from collapsing and helps to open alveoli that are already collapsed.73,74 With almost 70 years of use in the hospital and home set- A number of other physiologic benefi ts have also been ting, continuous positive airway pressure (CPAP) devices are found with CPAP. The continuous pressure results in more slowly but surely making their way into the fi eld of prehospi- laminar (less turbulent) airfl ow. It has been associated with tal care.68–72 Simple, more lightweight, and considerably less improved oxygenation and ventilation, mainly through expensive technology has placed this mode of airway care improved diffusion and greater gas exchange surface area. into the reach of most EMS systems. There are a number of clinical benefi ts from these effects. Non-Intubating Airway Management 413 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. However, there are some limitations to CPAP. It does not gas leak through the CPAP valve. Although most patients will provide positive pressure ventilation; there is no difference receive adequate gas fl ow from a fi xed fl ow generator, there are in gas fl ow between inhalation and exhalation. Furthermore, some whose inspiratory effort and negative pressure will be the effects of CPAP are limited to the alveoli and the small in excess of the gas fl ow. When this happens, the CPAP valve airways. Large airway diseases are not effectively treated. closes and the pressure in the system drops below the level of CPAP has been used in a number of disease processes. the CPAP valve. For these patients, the variable fl ow genera- The most common prehospital application has been for tor allows the Paramedic to increase the gas fl ow to compen- patients with congestive heart failure. Not only does CPAP sate for the patient’s high demand. In addition, although the address atelectasis, but it also helps to drive edema back into hypoxia these patients experience is usually due to a diffusion the circulatory system by decreasing preload and afterload problem (not enough oxygen moving from the alveoli to the via increased intrathoracic pressure. Several prehospital trials bloodstream), some patients do need higher oxygen concentra- suggest that using CPAP decreases intubation rates, improves tions. The variable fl ow generators usually allow the Paramedic patient symptoms, and decreases myocardial damage during to adjust the oxygen concentration as well. Therefore, although the acute phase of CHF.75–80 No trial to date has demonstrated the variable fl ow generators are more complicated to use, they a long-term mortality difference. Nonetheless, there are more give the Paramedic fl exibility for the occasional patient whose important markers of the effectiveness of the treatment of needs exceed the capabilities of the fi xed fl ow generators. CHF than just mortality and CPAP has certainly been demon- CPAP is relatively simple to use (Skill 22-1). The CPAP strated to be effective in regards to these other markers. generator is attached to a 50 PSI oxygen source. A fi lter is CPAP has also been used in the treatment of COPD and attached to the air intake valve and the high-volume tubing asthma. There appear to be two main effects. First, turbulent is attached to the generator output port. An appropriate-sized airfl ow increases the work of breathing. The laminar airfl ow mask is selected, the high volume tubing is attached to the produced by CPAP, therefore, decreases the work of breathing. input port, and the head restraint is attached to the mask, leav- Additionally, infl ammation plays an important role in asthma ing one side open if possible. If the mask uses interchange- and chronic bronchitis. During acute exacerbations, CPAP able CPAP valves, the appropriate valve (usually 5 to 10 cm may help to decrease the edema in the walls of the airways. H O) is attached. If there is an adjustable valve, it is set to the 2 Although CPAP has been studied extensively in COPD, there lowest setting. If there is a built-in CPAP valve, no further is minimal literature on its utility in acute asthma. Therefore, preparation is necessary. the two main prehospital indications for CPAP are COPD Next, the oxygen is turned on. If the generator has exacerbations and acute pulmonary edema. an on/off knob or switch, it should also be turned on. The CPAP devices have become smaller and much easier to system will begin fl owing oxygen. The mask is handed use. Although nasal CPAP devices are used effectively in the to the patient, who should hold it to his face without sleep apnea populations and in some inpatient settings, full sealing the mask. The patient should be allowed to exhale face-mask CPAP is the most commonly used modality in against the CPAP valve without the mask being completely the prehospital and emergency department settings. The two sealed; this will reduce the feeling of suffocation the patient main categories of CPAP devices for prehospital use are the experiences. Once the patient begins to feel comfortable fi xed fl ow devices and the variable fl ow devices. breathing against resistance, the mask should be fi rmly sealed The fi xed fl ow devices are typically the easiest to use. against the face. The head strap should then be brought into They have no moving parts and no adjustments. The device is place and the last leg attached. The mask and head strap designed to deliver a fi xed fl ow of gas at a set oxygen percent- should be adjusted so that the mask seals against the face and age (usually 30% to 35%). The CPAP generator is attached there are no leaks. to a 50 PSI oxygen source, the mask and tubing are attached, The patient should then be assessed for comfort and abil- and a CPAP valve is selected. Some devices use a fi xed level ity to breathe with the level of CPAP. If the patient cannot of CPAP, others allow the user to switch between different tolerate the CPAP, the level can be reduced (if not already valves (typically 5, 7.5, and 10 cm H O), and some use an at its |
lowest level) or the mask seal can be broken to slightly 2 adjustable valve. Thus, although the gas fl ow and oxygen con- decrease the pressure in the system. If the patient is tolerating centrations are preset with these devices, the level of CPAP the CPAP he is on, it may be possible to increase the level. can usually be adjusted. Usually a level of 5 to 10 cm H O is appropriate. Generally 2 In contrast, the variable fl ow devices allow the Paramedic 15 cm H O is considered to be the upper limit. If a CPAP 2 some degree of choice in determining gas fl ow and oxygen of 15 cm H O or greater is used, a nasogastric (NG) tube 2 concentration. In order to maintain the minimum CPAP pres- should be placed. There should always be a small air leak sure (the valve pressure) throughout the entire respiratory from the CPAP valve, even during inspiration. If there is no cycle, there must be suffi cient gas fl ow to keep the CPAP valve leak and a variable fl ow generator is being used, the fl ow can slightly open at the point of most negative intrathoracic pres- be increased until there is an air leak. In addition, the patient sure. This point occurs during early inspiration. During the may benefi t from an anxiolytic. However, care must be taken rest of the respiratory cycle, there will be a more signifi cant not to depress the respiratory drive. 414 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. The patient must be observed for tolerance, improvement, The posterior occiput is signifi cantly more prominent or decompensation.81 Since the CPAP provides no ventilatory in the pediatric patient than in the adult.82 Therefore, when support, the patient must not be apneic. The patient is, how- the pediatric patient lays on a fl at surface, the neck is fl exed ever, at an increased risk for pneumothorax. Additionally, and the airway partially obstructed. To counter this, the the patient may begin to fatigue and decompensate before Paramedic should place a folded towel beneath the shoul- atelectasis begins to resolve. If this happens, the patient may ders so that the head rests in a neutral position. Conversely, need to be intubated or the CPAP switched to assisted ventila- the pediatric trachea is smaller and more susceptible to tion. The patient should be attached to a pulse oximeter, vital kinking. When the head is extended, there is a potential for signs should be obtained, and the EKG (rhythm strip) should the trachea to kink and become occluded. Therefore, head be monitored. extension should be done carefully, again with the intent to In addition, end-tidal carbon dioxide monitoring can be per- keep the head in a relatively neutral position. formed. This has never been formally studied but, anecdotally, a In addition, the nasal bridge of the pediatric patient is small but consistent waveform is seen. Therefore, the end-tidal fl atter than an adult’s. The mask, therefore, is more diffi cult CO monitor may offer an apnea alarm. to seal. Due to the fl exibility of the airway, however, increas- 2 If the patient is switched to positive pressure assisted venti- ing pressure on the mask puts the patient at increased risk lation, it may be possible to attach a positive end expiratory pres- for airway obstruction. Therefore, a two-rescuer approach to sure valve to the exhalation port and, in essence, provide CPAP if ventilation is often more successful. the patient is also breathing on his own. There are no studies on Ventilating the pediatric patient requires care to pre- using the PEEP valves this way, but they should serve the same vent overpressurization. Causing a pneumothorax in a function if a good mask seal is maintained. pediatric patient is relatively easy and may be diffi cult CPAP has clearly been demonstrated to decrease intu- to diagnose in the prehospital environment. Additionally, bation rates and to provide symptomatic improvement in pediatric patients are more susceptible to gastric infl a- prehospital patients with congestive heart failure. It is also tion and are less able to tolerate it. Therefore, ventilation effective for patients with COPD and may be effective with should be suffi cient to just cause the chest to start to rise. asthma as well. CPAP is easy to use and may free a provider Although cricoid pressure can be used to decrease the risk who would otherwise need to provide assisted ventilation. of gastric infl ation and vomiting, the relatively malleable Concurrent treatment for the underlying disease should also trachea puts the pediatric patient at risk for complete air- be performed: loop diuretics, morphine, nitrates, and oxygen way obstruction with excessive pressure. for CHF and albuterol, ipratropium bromide, and steroids for Pediatric patients generally suffer cardiac arrest sec- COPD and asthma. When used appropriately, improved pre- ondary to respiratory arrest, as opposed to adults who suf- hospital outcomes should be seen. fer primary cardiac arrest.83–85 Once a pediatric patient goes For a step-by-step demonstration of Application of into cardiac arrest, a grim prognosis is almost assured. Continuous Positive Airway Pressure, please refer to Therefore, Paramedics must be more aggressive about pro- Skill 22-1 on page 416. viding early interventions and early respiratory support. As Gausche–Hill and her colleagues have demonstrated, the key to management of pediatric respiratory emergencies is Pediatric Considerations in Basic not in the advanced skills, but rather in the basic airway Airway Management manipulation and face-mask ventilation.86 Therefore, con- stant retraining and practical experience are key elements to In general, the techniques of basic adult and pediatric airway performing effective pediatric airway management. management are the same. However, there are a few impor- tant differences with which the Paramedic must be familiar. These relate to differences in anatomy and physiology. Non-Intubating Airway Management 415 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Skill 22-1 Application of Continuous Positive Airway Pressure 2 Set fl ow rate on device per manufacturer’s recommendations and protocol. 1 Assemble equipment. 3 Apply face mask to patient and snug down straps. 416 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Skill 22-1 (continued) 4 Coach patient to breathe with the mask. 5 Monitor and reassess the patient. Non-Intubating Airway Management 417 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Although tracheal intubation remains the “gold standard” of airway management, basic airway management is the most critical and fundamental airway management that the Paramedic can perform. Whether that provider is an EMT, a Paramedic, a nurse, or a physician, knowledge and skill in basic airway management is mandatory. Expertise with a number of skills and devices allows the Paramedic to ventilate patients through simple face-mask techniques. In addition, CPAP and other advances in airway technology allow critically ill patients to be managed without the need for intubation. The Paramedic should advocate for the best possible care for his patients and basic airway management is often just what the patient needs. Key Points: • Preoxygenation for any patient in need of active • The use of a venturi mask in the prehospital setting airway management or ventilatory support increases is generally limited to specialty care services. the diffusion gradient of oxygen into the plasma. It also provides a “reservoir” of oxygen in the lungs • Oropharyngeal and nasopharyngeal airways in the event the patient becomes apneic. Oxygen facilitate displacement of the most common therapy can also decrease the patient’s respiratory anatomic structures that obstruct the airway: the distress, in turn decreasing catecholamine release soft palate and the epiglottis. and myocardial oxygen demand. • The bag-mask assembly is the most commonly used • Compressed oxygen cylinders are the most common device for providing assisted ventilation and is method of storing oxygen in the prehospital available in adult and pediatric sizes. environment. • Excellent bag-valve-mask technique is important to • A regulator is used to decrease the pressure from prevent overventilation of the patient and gastric which oxygen is stored to a tolerable level suitable infl ation. In addition to technique, the mask must for patient use. be appropriately sized. • The nasal cannula is a pronged device designed for • Barrier devices and pocket masks can provide a nasal oxygen delivery at a rate of 0.5 to 6 LPM and good alternative to one-rescuer bag-mask assembly can deliver up to a 40% FiO2. ventilation until assistance arrives. • The simple face mask seals over the mouth and nose • Manually triggered fl ow-regulated, oxygen-powered and delivers oxygen and room air drawn in through ventilation devices deliver high oxygen fl ow rates an open side port. The mixture of room air and (40 LPM) while using oxygen only during the oxygen at 10 LPM can produce a FiO2 of 40% to 60%. “inhalation” phase of ventilation. • Oxygen delivered via a nonrebreather mask is not • Manually triggered fl ow-regulated, oxygen-powered diluted by room air and uses a reservoir bag and ventilation devices have a limited amount of one-way valve to ensure a continuous inspiratory research that compares these devices to other fl ow of oxygen to the patient. The nonrebreather ventilation devices. face mask can deliver up to 80% FiO2. • Automatic transport ventilators (ATVs) are • A demand valve regulator can provide 100% FiO mechanical devices that deliver a specifi ed volume 2 by delivering high LPM fl ows of 100% oxygen upon of respiratory gas and allow one rescuer to deliver inspiration. consistent tidal volumes at a set rate. 418 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. • The suction unit is used to remove vomit, blood, • It is diffi cult for a single rescuer to provide effective and some foreign bodies from a patient’s airway. tidal volumes while simultaneously forming a • proper mask seal, maintaining an open airway, and The patient should be pre- and postoxygenated and squeezing the bag. Two-rescuer, and even t hree- the Paramedic should suction for no more than rescuer, ventilation techniques are more commonly 15 seconds while withdrawing the tip. performed and preferred. • A rigid pharyngeal suction catheter known as a • While continuously monitoring the patient, the Yankauer or a soft sterile suction catheter is useful most important assessments are observation, in the prehospital environment. auscultation, and physiologic monitoring. • The most common anatomical cause of airway • A complete reassessment of airway, breathing, obstruction is the epiglottis |
and the soft palate, and circulation, including lung fi elds and epigastric so airway management techniques are oriented auscultation, should be performed anytime a toward establishing a patent hypopharynx. patient’s status changes. After observation and • The modifi ed jaw thrust must be used for patients auscultation, the patient should have physiologic with suspected cervical spine injury. signs measured and monitored. These include pulse, blood pressure, EKG, and pulse oximetry. • Cricoid pressure is a non-invasive technique that, when maintained continuously, can limit the risk • While reevaluating the airway, the Paramedic of aspiration and decrease gastric infl ation during should be prepared to suction any foreign bodies, positive pressure ventilation. blood, or vomit from the airway. • Limitations to cricoid pressure include excessive • Some conscious and breathing patients may present with insuffi cient ventilatory efforts and will benefi t posterior pressure with patients with suspected from assisted ventilatory support commonly C-spine injuries, possible laryngeal trauma or provided via a BVM. esophageal rupture, and in pediatric patients possible occlusion of the trachea. • During the normal respiratory cycle, the • intrathoracic pressure becomes negative during Bag-valve-mask ventilation requires an effective inspiration, zero at the end of inspiration, positive mask seal plus an open airway. during expiration, and zero again at the end • When ventilating, the trachea usually offers the of expiration. The alveoli can collapse at zero path of least resistance but excessive volumes of air pressure, resulting in atelectasis. will end up in the stomach. • Continuous positive airway pressure (CPAP) is used • It is best to deliver a tidal volume of 6 to 8 cc/kg to re-expand collapsed alveoli caused by alveolar ideal body weight/breath. wall breakdown or insuffi cient surfactant that would otherwise decrease gas exchange surface area. • With ventilatory rates of 12 to 16 breaths per minute for adults and 20 breaths per minute • Two main prehospital indications for CPAP are COPD for pediatric patients, the inspiratory phase of exacerbations and acute pulmonary edema. ventilation should occur over two seconds and • CPAP delivery devices for prehospital use are either the expiratory phase should take about the same fi xed fl ow devices or variable fl ow devices. Variable amount of time. fl ow devices allow the Paramedic to increase gas • The average adult bag-valve-mask assembly fl ow to compensate for a patient’s high demand or holds 1,600 mL, and approximately one third of adjust the oxygen concentration, FiO2. the volume of that bag would be delivered for • When using CPAP, the patient must be observed for a 70 kg patient. tolerance, improvement, or decompensation. Non-Intubating Airway Management 419 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. • For pediatric patients, head fl exion and extension • More successful outcomes of pediatric respiratory may partially obstruct or occlude the airway when emergencies have been demonstrated not with performing airway maneuvers and ventilations. The advanced skills but rather with basic airway pediatric patient’s head should rest in a relatively manipulation and face-mask ventilation. neutral position and a two-rescuer approach to ventilation is recommended. Review Questions: 1. Why is preoxygenation important for any 7. When using an automatic transport ventilator, patient in need of active airway management or what should the Paramedic specifi cally monitor ventilatory support? for while performing her ongoing assessment? 2. Compare and contrast the characteristics of, 8. Why is it important to know how much air a bag and indicated uses for, a nasal cannula and a valve device holds? nonrebreather face mask. 9. Describe one-, two-, and even three-rescuer 3. Describe the process measuring oropharyngeal ventilation techniques. and nasopharyngeal airways. 10. After opening the patient’s airway and 4. Before ventilating the patient with a bag-valve successfully ventilating him, what continuing mask, how is the appropriate size selected for ventilatory care should be carried out? the patient? 11. Name two indications for CPAP and explain 5. Describe the proper technique for mask-to-face how CPAP is benefi cial to both. interface. 12. How would one assess the adult and pediatric 6. What is the signifi cance of the 30 cm water patients for appropriate ventilation? when ventilating the patient? Case Study Questions: Please refer to the Case Study at the beginning of the 3. What hemodynamic effects does CPAP cause? chapter and answer the questions below: 4. What physiologic signs must the Paramedic assess 1. How does CPAP decrease the work of breathing? when using CPAP? 2. Describe how CPAP increases oxygenation. 420 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. References: 1. Larmon B, Schriger DL, Snelling R, Morgan MT. Results of a 21. Taylor DM, Bernard SA, Masci K, Macbean CE, Kennedy MP. 4-hour endotracheal intubation class for EMT-Basics. Ann Emerg Prehospital noninvasive ventilation: a viable treatment option in Med. 1998;31(2):224–227. the urban setting. 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Heart Fail Rev. 2007;12(2): Care Med. 2005;6(3):293–297. 119–124. 50. Willis DH, Jr., Liberti JP. Post-receptor actions of somatomedin 68. Goss JF, Zygowiec J. Positive pressure: CPAP in the treatment of on chondrocyte collagen biosynthesis. Biochim Biophys Acta. pulmonary edema & COPD. Jems. 2006;31(11):48, 50, 52–58 1985;844(1):72–80. passim; quiz 64. 51. Conlon NP, Sullivan RP, Herbison PG, Zacharias M, Buggy DJ. 69. Sullivan R. Prehospital use of CPAP: positive pressure positive The effect of leaving dentures in place on bag-mask ventilation at patient outcomes. Emerg Med Serv. 2005;34(8):120, 122–124, 126. 422 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. 70. Hubble MW, Richards ME, Jarvis R, Millikan T, Young D. 78. Pang D, Keenan SP, Cook DJ, Sibbald WJ. The effect of positive Effectiveness of prehospital continuous positive airway pressure pressure airway support on mortality and the need for intubation in the management of acute pulmonary edema. Prehosp Emerg in cardiogenic pulmonary edema: a systematic review. Chest. Care. 2006;10(4):430–439. 1998;114(4):1185–1192. 71. Kosowsky JM, Gasaway MD, Stephanides SL, Ottaway M, Sayre 79. Park M, Sangean MC, Volpe Mde S, Feltrim MI, Nozawa E, Leite MR. EMS transports for diffi culty breathing: is there a potential PF, et al. Randomized, prospective trial of oxygen, continuous role for CPAP in the prehospital setting? Acad Emerg Med. positive airway pressure, and bilevel positive airway pressure 2000;7(10):1165. by face mask in acute cardiogenic pulmonary edema. Crit Care 72. Hatlestad D. Calming the waters: noninvasive positive pressure Med. 2004;32(12):2407–2415. ventilation in prehospital care. Emerg Med Serv. 2002;31(5): 80. Mehta S, Jay GD, Woolard RH, Hipona RA, Connolly EM, 67–71, 74. Cimini DM, et al. Randomized, prospective trial of bilevel versus 73. Schreiter D, Reske A, Stichert B, Seiwerts M, Bohm SH, continuous positive airway pressure in acute pulmonary edema. Kloeppel R, et al. Alveolar recruitment in combination with Crit Care Med. 1997;25(4):620–628. suffi cient positive end-expiratory pressure increases oxygenation 81. Duncan AW, Oh TE, Hillman DR. PEEP and CPAP. Anaesth and lung aeration in patients with severe chest trauma. Crit Care Intensive Care. 1986;14(3):236–250. Med. 2004;32(4):968–975. 82. Gausche-Hill M. Pediatric Airway Management for the Pre- 74. Karmrodt J, Bletz C, Yuan S, David M, Heussel CP, Markstaller Hospital Professional. Sudbury: Jones and Bartlett Publishers, K. Quantifi cation of atelectatic lung volumes in two different Inc.; 2005. porcine models of ARDS. Br J Anaesth. 2006;97(6):883–895. 83. Bardella IJ. Pediatric advanced life support: a review of the 75. Moritz F, Brousse B, Gellee B, Chajara A, L’Her E, Hellot AHA recommendations. American Heart Association. Am Fam MF, et al. Continuous positive airway pressure versus bilevel Physician. 1999;60(6):1743–1750. noninvasive ventilation in acute cardiogenic pulmonary edema: a 84. Wright JL, Patterson MD. Resuscitating the pediatric patient. randomized multicenter trial. Ann Emerg Med. 2007;50(6): Emerg Med Clin North Am. 1996;14(1):219–231. 666–675. 85. Hickey RW, Cohen DM, Strausbaugh S, Dietrich AM. Pediatric 76. Ursella S, Mazzone M, Portale G, Conti G, Antonelli M, patients requiring CPR in the prehospital setting. Ann Emerg Gentiloni Silveri N. The use of non-invasive ventilation in the Med. 1995;25(4):495–501. treatment of acute cardiogenic pulmonary edema. Eur Rev Med 86. Gausche M, Lewis RJ, Stratton SJ, Haynes BE, Gunter Pharmacol Sci. 2007;11(3):193–205. CS, Goodrich SM, et al. Effect of out-of-hospital pediatric 77. Winck JC, Azevedo LF, Costa-Pereira A, Antonelli M, Wyatt JC. endotracheal intubation on survival and neurological outcome: a Effi cacy and safety of non-invasive ventilation in the treatment controlled clinical trial. Jama. 2000;283(6):783–790. of acute cardiogenic pulmonary edema—a systematic review and meta-analysis. Crit Care. 2006;10(2):R69. Non-Intubating Airway Management 423 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. KEY CONCEPTS: Upon completion of this chapter, it is expected that the reader will understand these following concepts: • The implements of intubating airway management • End-tidal carbon dioxide monitoring, the “gold standard” of proper placement • Principles of patient airway assessment and how to make the fi rst attempt at endotracheal intubation the best attempt • A backup plan, using rescue devices when faced with a diffi cult airway • Post-intubation care and special considerations in airway management Case Study: The patient was in cardiac arrest and emergency medical responders had been doing CPR before the arrival of the Paramedics. The patient’s stomach was distended and she had vomited. Despite the best efforts of the responders, the airway could not be cleared with suctioning alone and the risk of aspiration was growing. “This patient will need to be intubated to protect that airway as soon as possible,” thought the arriving Paramedic. 424 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Intubating Airway Management 425 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. OVERVIEW Endotracheal intubation remains the defi nitive airway management technique, even though it is a complex procedure which requires constant practice in order to remain profi cient. Even under the best of circumstances, there are times when the Paramedic cannot intubate a patient. Therefore, it is important for the Paramedic to have a plan for that situation and alternative ways of managing the airway. The Paramedic must also provide continuous care for the intubated patient and be prepared for aberrant circumstances in airway management. The Advanced Airway Management Algorithm, together with the skills covered in this chapter and the last, should provide the Paramedic with the necessary tools to perform airway management and continuing supportive care. This chapter examines the use of intubating airway management and the principle of patient airway assessment to make the Paramedic’s fi rst attempt at endotracheal intubation the best attempt. The Intubating Airway the patient is in need of active airway management. The Paramedic begins by preoxygenating the patient and, if neces- Management Algorithm sary, ventilating the patient using the techniques discussed in The Intubating Airway Management Algorithm (Figure 23-1) Chapter 22. Once these interventions have been assured, the begins with the same assessment completed in Chapter 21: Paramedic must prepare his or her equipment. Patient assessment: Patient needs to be intubated Preoxygenate, ventilate PRN, prepare equipment If patient is breathing, consider nasal intubation Yes Attempt orotracheal intubation: • Confirm position Successful? with 3 methods. No • Secure tube. • Monitor patient. Ventilate. Reassess provider, patient, and equipment. • Confirm position with 3 methods. Yes • Secure tube. Attempt intubation (x 2): Successful? • Monitor patient. No Ventilate, prepare Blind Insertion Airway Device • Confirm position Yes with 3 methods. Attempt BIAD placement: Successful? • Secure tube. No • Monitor patient. Attempt to ventilate with BVM/ATV: Yes Monitor patient, Successful? transport No emergently Consider obstructed airway. If unable to clear Yes Monitor patient, obstruction, attempt surgical airway: Successful? transport No emergently Transport patient emergently. Consider requesting physician intercept. Figure 23-1 Intubating airway management algorithm. 426 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Equipment for Intubating Airway Management By far, the most common technique used to intubate patients is orotracheal intubation using direct laryngoscopy. A lar- yngoscope is used to visualize the larynx and the vocal cords, and an endotracheal tube is observed to pass through the vocal cords. Although simple in description, there are nuances to the equipment and procedure that can make intubation more or less easy. In addition, numerous other methods of intubation—such as nasotracheal intubation, digital intubation, fi beroptic assisted intubation, and lighted wand techniques— exist and are potentially important tools in the Paramedic’s armamentarium. Endotracheal intubation offers many advantages over Figure 23-2 Endotracheal intubation equipment. other techniques. An endotracheal tube offers direct access to a patient’s airway that is relatively protected. Intermittent p ositive pressure ventilation, tracheobronchial suctioning, and medication delivery are all possible. Although an endotracheal Table 23-1 List of Suggested Contents tube does not absolutely prevent aspiration, it signifi cantly of an Airway Management Kit decreases the likelihood of aspiration. One of the g reatest • Laryngoscope handles (adult and pediatric) advantages of the endotracheal tube over non- intubated ven- • Miller blades (00 to 4) tilation is that it does not cause gastric insuffl ation and the • Macintosh blades (1 to 4) resulting distention, impingement on thoracic expansion, and • Full set oral airways vomiting. However, there are some disadvantages to endotracheal |
• Full set nasal airways intubation. Endotracheal intubation bypasses the natural • Uncuffed endotracheal tubes (2.5 to 5.5) functions of the upper airways including fi ltration, warm- • Cuffed endotracheal tubes (5.0 to 10) ing, and humidifi cation. Complications of intubation include • 10 cc syringe (2) bleeding from the placement of the tube and from the manip- • Stylettes (adult and pediatric) ulation of soft tissues with the laryngoscope. Laryngospasm, • Elastic gum bougie (adult and pediatric) laryngeal swelling, mucosal necrosis and erosion, and vocal • Tape cord damage can all result from endotracheal intubation. In • Rescue device (King airway, LMA, etc.) addition, the direct connection from the ventilation device • Magill forceps (adult and pediatric) to the lungs increases the risk of barotrauma and ventilator- a ssociated pneumonia. Overventilation of the lungs can • Tube-securing device (adult and pediatric) impede venous return by increasing intrathoracic pressure, • Esophageal intubation detection device which can decrease the systemic blood pressure. However, • End-tidal carbon dioxide detector or adapters for capnometry/ prehospital endotracheal intubation occurs in the setting of capnography life-threatening diseases. If a patient requires intubation, then • Stethoscope the benefi ts far outweigh the risks. • Spare bulbs and batteries Although each different intubation technique necessi- • Extra PPE tates the use of a specifi c set of equipment, there are some fundamental pieces of equipment which are standard tools of the Paramedic. These include endotracheal tubes, laryn- goscope handles, laryngoscope blades, syringes, stylettes, gum bougie, continuous positive airway pressure (CPAP), endotracheal tube securing supplies, and Magill forceps and surgical airway management techniques—may also be (Figure 23-2, Table 23-1). In addition, endotracheal tube con- part of a Paramedic’s practice. Understanding the prepara- fi rmation equipment (stethoscopes, end-tidal carbon dioxide tion and use of these devices is critical for excellent airway monitors and detectors, and esophageal detection devices) management. and airway rescue devices (King airway, laryngeal mask air- ways, and esophageal tracheal Combitubes) should also be Endotracheal Tubes part of the Paramedic’s standard airway management equip- The basic tool of endotracheal intubation is the endotra- ment. Finally, some specialty devices—such as direct fi berop- cheal tube (Figure 23-3). The endotracheal tube provides tic intubation devices, direct visualization devices, the elastic a conduit for oxygenation and ventilation between the Intubating Airway Management 427 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. patient’s small fi nger or nare, or length-based tapes that give the Paramedic all of the appropriate sizes of equipment and drug doses. Although there is some evidence to suggest that length-based tapes are superior to other methods,2–4 it has been demonstrated that Paramedics can accurately determine weights of pediatric patients. Therefore, any method may be used as long as it is practiced and used consistently. Nasotracheal intubation, placing an endotracheal tube through the patient’s nostril and into the trachea, is another commonly used technique for managing a breath- ing patient’s airway. Blind nasotracheal intubation can only be performed on a breathing patient. While a standard endotracheal tube can be used for nasotracheal intubation, special tubes for nasal intubation are different in many ways from a standard oral endotracheal tube (Figure 23-4). Nasal tubes are softer and more pliable than standard tubes to allow them to curve more easily along the pos- Figure 23-3 Endotracheal tubes. terior oropharynx. Endotrol® tubes also have a small ring or “trigger” that, when pulled, decreases the radius of the tube’s curvature and curves the tip of the tube anteriorly. patient’s lungs and the ventilator (person or machine). The When compared to using standard endotracheal tubes for primary components of an endotracheal tube are the tube, nasotracheal intubation, “trigger tubes” increase the rates the cuff (on cuffed tubes), and the 15 mm adapter. The tube of successful intubation.5 acts as a gas conduit. The adapter allows the tube to be con- Once the Paramedic has selected the appropriate size and nected to a bag-valve-mask device or ventilator. The cuff style of endotracheal tube, the next matter is to check and (used on adult tubes) infl ates to secure the tube and to form prepare the tube. The Paramedic opens the tube packaging a tight seal below the level of the cords. Pediatric tubes are and places a small amount of lubricant at the distal end of the uncuffed because the pediatric trachea cones down in diam- tube. Although not a “sterile” technique, airway management eter below the cricoid ring, allowing the uncuffed tube to should at least be a “clean” technique. Efforts should be made seal itself there. However, cuffed endotracheal tubes can be to minimize contamination of the endotracheal tube. If the used in pediatric patients, particularly at the transition ages tube is cuffed, the Paramedic should place 5 to 10 cc of air in (ages 5 to 8). the cuff with a syringe and gently squeeze the cuff to assure There are some common features of all endotracheal that it is not leaking. tubes. The length of the tube is noted on the outside and is The syringe should be removed from the infl ation port measured in centimeters. These markings allow the Paramedic to assure that the valve is working and then reattached to to measure the depth to the end of the endotracheal tube. The aspirate the air from the cuff. The syringe should be fi lled distal end of an endotracheal tube is beveled. In addition, with 10 cc of air and left attached to the infl ation port so there is a “Murphy eye” on the distal right side of the tube. that it is ready and easy to fi nd at the time of intubation. The The Murphy eye improves ventilation to the right upper lobe 15 mm adapter should be assessed to make sure it is snugly and allows for some ventilation through the tube if the distal attached. For orotracheal intubation, a stylet (described in the end becomes occluded. following text) is placed and appropriately shaped, and the Endotracheal tubes are sized based on their internal prepared tube (still in its package) is placed within reach of diameter (I.D.). The smallest tube commonly used is the 2.5 the Paramedic at the patient’s side. mm I.D. tube, while the largest is the 11.0 mm I.D. tube. The well-prepared Paramedic recognizes that, although Endotracheal tubes increase in half-millimeter steps from 2.5 there are general size ETTs used for general “groups” (adult to 11.0 mm. Selection of the size of the endotracheal tube male, adult female, etc.), the availability of multiple sizes of for use with a given patient is made based on experience and endotracheal tubes (typically one smaller and one larger than the circumstances of the particular intubation. In general, an the expected size) allows the Paramedic to quickly use an adult male will be able to accommodate an 8.0 to 8.5 mm appropriately sized tube if the fi rst attempt was not success- tube while an adult female will accommodate a 7.5 to 8.0 mm ful due to endotracheal tube size. Some endotracheal tubes tube. However, patients with airway edema or trauma may are available preloaded with a stylet (“Slick Set®” Stylettes). require a smaller endotracheal tube. Regardless of how the Paramedic prepares for an inappropri- Sizing endotracheal tubes for pediatric patients can ately sized tube, it is important that she at least be aware that be done based on formulas that calculate an appropriate the fi rst ETT may not work and have a plan for what to do if size based on age,1 estimates based on the diameter of the that happens. 428 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Figure 23-4 Endotrol “trigger” endotracheal tube. The Laryngoscope The laryngoscope is the primary device used to visualize the larynx. Since its original design, the laryngoscope has under- gone a number of revisions to make it a more compact and self-contained device, affording improved visualization in some instances. Regardless of these changes, the basic prin- ciple remains the same: to allow direct visualization of the larynx. There are two major components of the laryngoscope: the handle and the blade. The handle serves as a power source (or power and light source in the case of fi beroptic laryn- goscopes) and grip point for the Paramedic. There are four Figure 23-5 Variety of handle sizes. common sizes of handles (Figure 23-5): large adult, adult, pediatric, and neonatal. One of the two adult sizes and a pediatric handle are the typical complement for an intuba- tion kit. The neonatal handles may be seen in the obstet- ric and neonatal transport setting. Although the handles are labeled adult and pediatric, perhaps the more important dif- ferentiation is the Paramedic’s hand size. A single laryngo- scope s ystem (standard versus fi beroptic and reusable versus disposable) should be used to prevent having incompatible blades and handles in a single kit. If this rule is followed, then all the handles should work with all of the blades in the set. A Paramedic with small hands may fi nd that using the pediat- ric handle with an adult blade is the best for him. Although there are multiple types of laryngoscopic blades available, the two most commonly used styles of blades are Figure 23-6 The two most common types of the Macintosh and Miller blades (Figure 23-6). Regardless laryngoscope blades are the Macintosh on the left of the type of blade, almost all blades in service are right and the Miller on the right. Intubating Airway Management 429 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. handed; that is, the laryngoscope is held in the left hand and children under 5, the epiglottis tends to be fl oppy and the the intubation is performed with the right hand. Although vallecular placement of the Macintosh blade does not pro- left-handed blades are available, unless the Paramedic plans vide suffi cient epiglottic control. The use of the Macintosh to purchase his own set, it is best to learn to use right-handed blade is described later. blades. Blades are designed to provide a view of the laryn- The Miller blade is a straight blade with common sizes geal opening through control of the tongue and the epiglottis. from 00 to 4. The small and curved fl ange is not designed The major differences between Macintosh and Miller blades, to displace the tongue in the same manner as the Macintosh refl ected in their design, are in the manner in which they con- blade (Figure 23-9). Rather, the straight blade is designed to trol the tongue and epiglottis. open a conduit to the larynx on the right side of the mouth The Macintosh blade is a curved blade with common and hold the tongue in the midline to the left side of the sizes from 1 to 4 (Figure 23-7). Its large fl ange and fl at sur- mouth. The tip of the blade is designed to capture and lift the faces refl ect a design to control the tongue. The tip of the epiglottis (Figure 23-10). This feature makes the Miller more blade is intended to fi t into the vallecula (Figure 23-8) and desirable for the child under 5 years of age. |
The 00 Miller is elevate the epiglottis via the hyoepiglottic ligament. Although designed for premature neonates. The use of the Miller blade not intended to do so, some Paramedics use the tip to directly is described later. hook the epiglottis and control it in that manner. Selecting the appropriate size and type of blade depends Although small (size 1) Macintosh blades are avail- on the patient’s size and the clinical context. Commonly, a able, they are typically not used in children under age 5. In chart (or, in pediatric patients, a color-coded tape) is used Figure 23-7 Macintosh blade. Figure 23-9 Miller blade. Epiglottis Vallecula Epiglottis Figure 23-8 Proper placement of the Figure 23-10 Proper placement of the Macintosh blade. Miller blade. 430 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. to select the appropriate-sized blade. As mentioned, Miller Murphy’s eye on the endotracheal tube to decrease the risk of blades are typically used for children under 5 years of age. the stylet injuring the airway. For patients older than 5, selection of the appropriate blade Although the use of a stylet is not mandatory, it is a use- depends upon the provider’s comfort level. There is a recom- ful adjunct that almost always makes intubation easier. There mendation to use a Miller blade in trauma patients because it are adult and pediatric sizes as well. A technique of nasal may provide a better view with less cervical spine manipu- intubation using a stylet has been described, although, gener- lation. However, the Paramedic must select the blade with ally speaking, nasal intubation is carried out without a stylet. which he is most comfortable, as he will have to use that However, for all oral intubations, the use of a stylet should be blade in high-stress situations. the rule, not the exception. Once the Paramedic has selected the correct blade, it is important to prepare and test the laryngoscope. The blade is Securing Devices attached to the crossbar of the laryngoscope’s handle until Once an endotracheal tube is placed, it is important it clicks into place. The blade is then rotated until the power that it be secured to keep it from moving out of the tra- points or fi beroptic channel are in contact with the oppo- chea. Numerous devices, such as the Thomas tube holder site points on the handle and the blade locks into the top (Figure 23-12), are available commercially. In addition, of the handle. At this point, the light should activate. The many other ties have been used and can be equally effec- light should be “white, tight, and steady bright”: white in tive. Regardless of the device or technique used to secure color (clean blade), the bulb tightly screwed into the blade the endotracheal tube, it is important that the endotracheal receptacle (not necessary in fi beroptic laryngoscopes), and tube not be able to move. Although taping the endotracheal steady and bright in intensity (good contact and good batter- tube to a patient’s face may be an acceptable practice in an ies). The laryngoscope should be turned with the blade down operating room setting where the patient is not moved during (the position of intubation) to assure that contact is main- the procedure, it is not suffi cient for the prehospital envi- tained in that position. Finally, the blade should be folded ronment. The risks of accidental tube dislodgment during back down on the handle to keep the batteries draining and patient movement are high. Not only is it important to secure the bulb from getting too hot (hot enough to burn the patient) the tube with an adequate device or technique, but it is also or burning out. important to place a cervical collar to minimize neck exten- sion and fl exion.6 However the Paramedic plans to secure the Stylet neck, it is important that the equipment be prepared prior to The stylet, a commonly used adjunct to oral intubation, pro- the intubation. vides rigidity to the endotracheal tube. Made of a malleable material such as copper or alumi- Secondary Confi rmation Equipment num, the stylet is a long, thin rod placed in the endotracheal Although the process of confi rming tube placement will tube to combat the inherent fl exibility of the ETT. By straight- be described later, it is important that the Paramedic ening the proximal three quarters of the stylet and bending prepare his equipment for tube placement confi rmation the lower quarter into a “hockey stick” shape (Figure 23-11), prior to beginning intubation. The three most commonly the tube can be shaped to maximize control of its distal tip accepted methods of confi rming endotracheal tube place- and improve the chances of successful placement. It is impor- ment in the prehospital environment are auscultation, tant that the distal end of the stylet not extend beyond the esophageal detection devices (EDD), and end-tidal carbon Figure 23-11 Stylet in place. Figure 23-12 Thomas tube holder. Intubating Airway Management 431 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. dioxide measurement. Visualization of the endotracheal fact, the tube is actually in the trachea. This can occur when tube p assing through the vocal cords, although valuable the tip of the tube is on the carina or pushed against the tra- and highly recommended, may not be possible due to other chea’s wall. In addition, in patients with limited functional factors (e.g., traumatic airway, use of a elastic gum bougie, residual capacity—such as those in CHF, adult respiratory or nasotracheal intubation). distress syndrome, or the morbidly obese—the devices may Auscultation of lung sounds, listening to the lung fi elds infl ate slowly or with resistance.11,13 Therefore, the devices with a stethoscope, is a commonly accepted technique for must be used in conjunction with other methods. To pre- assessing endotracheal tube placement. The only equipment pare the equipment, the Paramedic needs only to open the necessary for this is a stethoscope. Therefore, a stethoscope packaging. should be immediately available. Although auscultation of the End-tidal carbon dioxide (ETCO ) measurement and 2 axilla alone to detect esophageal intubation is only 85% sen- monitoring has become a standard method of both confi rm- sitive (and therefore misses 15% of esophageal intubations), ing endotracheal tube placement and monitoring patient status, the combination of auscultation over the epigastrium and in ventilation, and continuing tube placement.14 Carbon dioxide is the axilla, when sounds can be well heard, has been shown a colorless, odorless gas that is produced during cellular metab- to be 100% sensitive (detected all) for detecting esophageal olism. It is the primary exhaled waste product and its concen- intubation.7 tration in the exhaled respiratory gasses depends on adequacy Esophageal intubation detection devices should also of ventilation and circulation. End-tidal carbon dioxide mea- be used to confi rm endotracheal tube placement. Two major surement is used to assess endotracheal tube positioning and to styles of these devices exist: self-infl ating bulbs and syringe monitor the adequacy of ventilation. The three classes of end- style aspirators (Figure 23-13). These devices operate on the tidal carbon dioxide measurement are colorimetric measure- principle that the esophagus is composed of soft, fl oppy mus- ment, capnometry, and capnography. culature while the trachea is held open by rings of cartilage. End-tidal carbon dioxide monitoring, in all of its forms, Therefore, if suction is applied to an endotracheal tube placed has been demonstrated to be a reliable and highly sensi- in the esophagus, the walls of the esophagus will collapse on tive method for assessing endotracheal tube placement and the tip and prevent infl ation. Conversely, the trachea will be monitoring tube placement over time.15–19 End-tidal carbon held open by cartilaginous rings. Therefore, the esophageal dioxide monitoring has become the gold standard of con- intubation detection device should infl ate rapidly and com- fi rming endotracheal tube placement. There are, however, pletely with air. conditions which can limit its reliability. Therefore, it is A number of studies have been performed on both the important to understand their impact on the use of these syringe type and self-infl ating bulb devices. The results are devices. Perhaps the most fundamental limit is that the encouraging for its use. In several studies,8–11 all of the esoph- patient must be producing carbon dioxide in order to exhale ageal intubations were detected. Although there are reports it. In patients in cardiac arrest, the lack of exhaled carbon of the devices failing to detect esophageal intubations in dioxide may be mistaken for an esophageal intubation.20 Of patients with massive gastric insuffl ations,12 this has not been much more c oncern, however, is the risk of mistaking an seen universally. The greatest limitation seems to be that the esophageal intubation for a tracheal intubation. Bag-mask devices will often indicate an esophageal intubation when, in assembly ventilation with gastric insuffl ations,21 ingestion of c arbonated beverages and antacids,22 and hypopharyn- geal endotracheal tube placement23 have all been shown to produce waveforms that would indicate tracheal intubation. However, with the exception of hypopharyngeal placement, after six ventilations (approximately 30 to 60 seconds of ventilation), the waveforms diminish and eventually vanish. Therefore, end-tidal carbon dioxide measurements should always be accompanied by other methods of assessing endo- tracheal tube placement. The least expensive, and probably most commonly used, device for measuring end-tidal carbon dioxide is the colorimetric device (Figure 23-14). These devices are simply encapsulated pieces of litmus paper over which the exhaled breath fl ows. When carbon dioxide is in the pres- ence of water, it forms carbonic acid; the pH sensitive lit- mus paper in the colorimetric device detects this acid and changes color. These devices are as reliable as infrared cap- nometry and capnography for detecting esophageal and tra- cheal intubations20 and are reliable in infants and children Figure 23-13 Esophageal detector devices. larger than 15 kg.24 The devices are designed to be attached 432 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. usually considerably less expensive than capnography devices although they are also much more expensive than disposable colorimetric caps. Most of these devices have a numerical as well as a bar graph display. Although they do not display trends over time nor show a graph of the exhalation curve, if the Paramedic records the peak ETCO over time it is possible 2 to collect trending data. In addition, these devices are usually equipped with an apnea alarm and can alert the Paramedic to sudden changes in ventilatory function. Preparation of the equipment for use involves assuring that there is suffi cient power. For a mainstream device, the probe must be attached to the monitor and an adapter that connects to the endotra- cheal tube (or alternative airway device) which should be attached to the probe. Sidestream and microstream monitors Figure 23-14 Colorimetric end-tidal carbon will have an adapter with a sampling tube that attaches to the dioxide detector. exhalation stream. End-tidal capnography gives the most information to the Paramedic. While numeric values for peak and trough between the 15 mm adapter on the endotracheal tube or an ETCO levels are displayed, the monitor also displays a graph 2 alternative airway device and the BVM. Some manufactur- of the exhalation |
curve (Figure 23-15). This graph allows for ers produce bag-mask assemblies with colorimetric ETCO 2 trending over time; demonstration of changes associated with devices built into the exhalation valves. When CO is < 0.5%, 2 complications such as displaced, kinked, and occluded tubes; the paper is purple. When the CO is between 0.5% and 2 and respiratory mechanics.19 Capnography monitors are by 2.0% of the exhaled gas, the paper becomes tan. Finally, far the most expensive, although they are often integrated when the exhaled CO is > 2%, the paper turns yellow. Over 2 into other multifunction devices such as cardiac monitors. time (approximately two hours for most in-line devices), the Preparation of these devices for use, as with the capnometer, paper turns permanently yellow. Exposure to water, vomit, depends on whether the capnographer is a mainstream or pulmonary secretions, medications, and so on, will hasten sidestream/microstream device. the deactivation of the device. Preparation of the colori- metric end-tidal CO monitor involves simply opening the Rescue Devices 2 packaging. For a patient requiring airway and ventilatory assistance, the The remaining two classes of monitoring—capnometry ideal situation is placement of an endotracheal tube. However, and capnography—are, outside of the operating room, based there will always be scenarios in which endotracheal intuba- on infrared analysis of exhaled gasses. By shooting an infrared tion will not be possible. A review of the airway management beam through a sample of exhaled gas, it is possible to measure algorithm clearly demonstrates that, after a third failed endo- the amount of CO in the sample based on the absorption of 2 tracheal intubation attempt, the Paramedic should strongly light in the correct wavelength. The infrared beam and sensor consider another approach to airway management. One class can either be attached directly to the gas exhaust stream, called of rescue devices available are placed blindly and provide mainstream or in-line monitoring, or can be housed in a device an airway that is superior to face-mask ventilation, yet not that takes a small sample from the exhaled gasses, called side- as protective as an endotracheal tube. These devices are col- stream or microstream monitoring. lectively called supraglottic airway devices or blind inser- Although mainstream measurements have the advantage tion airway devices (BIADs). The most common supraglottic of being instantaneous, the probes are more vulnerable to devices are the King LTS-D airway, the esophageal tracheal breakage and are more expensive. Sidestream devices protect Combitube (ETC or Combitube), and the laryngeal mask air- the infrared sensors, but they have a delay in measuring due way (LMA). Although the esophageal obturator airway (EOA) to the distance the gas sample must travel from the exhalation to the sample chamber. Microstream devices have less of a delay than standard 40 sidestream devices. Microstream devices may also be better suited for use in pediatric patients with very small tidal vol- umes than standard sidestream devices or bulky mainstream devices that can kink an endotracheal tube.25 Regardless of the sampling system, however, the data interpretation and display methods differentiate between capnometry and capnography. 0 Devices that perform capnometry give a single, numeric peak reading of the exhaled CO . These monitors are 2 Figure 23-15 Capnography waveform. Intubating Airway Management 433 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. mmHg and esophageal gastric tube airway (EGTA) were commonly operating room. Introduced in the mid-1980s, this device was used before the advent of the supraglottic airways, the need designed to be used in situations where face-mask ventila- to maintain an adequate mask seal and inability to protect the tion was inappropriate but the invasiveness of endotracheal trachea have decreased the use of the EOA and EGTA. intubation was not necessary.26 Although not originally The King LTS-D airway (Figure 23-16) is one example of designed as a “diffi cult airway” or “rescue” device, its poten- a supraglottic airway. It is designed to be placed in the esopha- tial was recognized early on. In the pilot study on its use, gus and seal off the pharynx and esophagus with two balloons two of the patients were classifi ed as having potentially dif- fi lled through a single port. A standard BVM adapter at the fi cult airways.27 Subsequent studies and clinical experience end of the device is used to ventilate the patient via small holes have demonstrated that the LMA adequately fi lls the role of located between the balloons. A channel located in the ante- a blind insertion airway rescue device in emergency airway rior between the two balloons allows the use of an elastic gum management.28 Furthermore, introduction of devices such as bougie or endotracheal tube exchanger to replace the device the intubating LMA (ILMA) and disposable LMAs (LMA with a standard endotracheal tube. Finally, a posterior lumen Unique®) have expanded the role of the LMA in prehospital allows for passage of a nasogastric tube into the stomach once airway management.29,30 the King airway is in place, allowing stomach decompression. The laryngeal mask airway, in essence, moves the mask Due to the ease of use, this device is becoming popular in the of face-mask ventilation from the face to the opening of the prehospital community. larynx. The LMA is composed of a single lumen tube with a The laryngeal mask airway (Figure 23-17), a blind standard 15 mm adapter at the proximal end and an infl atable rescue airway device, was originally designed for use in the mask at the distal end. The mask is designed to cover the open- ing of the larynx and, with the mask infl ated, provide a seal. The intubating LMA, in addition to placing the mask over the larynx, is designed to pass an endotracheal tube through the lumen and direct it into the trachea. The LMA Unique®, as a disposable device, is most likely to be used in the prehospital environment. The LMA does require some preparation before use. Once it is removed from the package, the mask should be infl ated to assure that it holds air. The LMA mask must then be pressed against a fi rm surface and the air aspirated from the mask. This causes the rim of the mask to fold backwards and allows for easier placement. Finally, the distal tip of the mask should be lubricated to improve ease of placement. The design of the esophageal-tracheal Combitube (ETC) (Figure 23-18) refl ects a response to the complica- tions associated with the esophageal obturator airway (EOA) and the esophageal-gastric tube airway (EGTA). Like the Figure 23-16 King LTS-D airway. Figure 23-17 Larnygeal mask airway. Figure 23-18 Esophageal-tracheal Combitube. 434 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. EOA and EGTA, the ETC is placed into the esophagus; how- King airway is not designed to be used if placed in the tra- ever, tracheal placement of the ETC is possible. The double- chea. If tracheal placement of the King airway is suspected, lumen design allows for endotracheal as well as esophageal immediately remove the device. intubation. Preparation of these devices is similar to that of an endo- The Combitube is a double-lumen device with two sepa- tracheal tube. They must be removed from their packages rate and distinct lumens, a proximal and distal lumen named and the cuffs infl ated to test their integrity and the function- by where they exit from the tube. Each lumen has a standard ing of the valves. For the King airway and Combitube, this is 15 mm connector at the proximal end to allow attachment to done with the syringes that are prepackaged with the device. a ventilation device. Each has two cuffs: a large proximal cuff The distal end of the tube should be lubricated with a water- designed to seal the hypopharyngeal portion of the airway soluble lubricant and the devices returned to the packaging. and a smaller distal cuff designed to seal the esophagus or trachea, depending on the placement. Elastic Gum Bougie There are several advantages and disadvantages to In those situations where intubation is diffi cult due to patient the use of supraglottic airway devices. Since they can be anatomy, often it is only possible to visualize the posterior passed blindly, no special equipment is needed other than arytenoids. Although any tube that passes anterior to the the device itself. The Combitube has been demonstrated to arytenoids will be passing through the larynx, it is often dif- cause less C-spine movement than conventional endotra- fi cult to physically place the tube in that location. A small cheal intubation,31 which may be clinically signifi cant in the diameter, semi-rigid device that would be easier to place patient with known or suspected C-spine injury. The devices would assist with intubation. The elastic gum bougie and are easy to place and have success rates of almost 100%.32 several similar devices meet that need. Placement is easier with these devices than with standard First introduced in 1949, the elastic gum bougie, or sim- intubation when patients are in unusual positions.33 There are, ply gum bougie, appears at fi rst glance to simply be a very however, multiple disadvantages to these devices. The King long stylet34 (Figure 23-19). However, it is somewhat larger airway and Combitube are currently only available for adult in diameter, is made entirely of wound gum rubber, and has patients. They must be inserted orally and, when placed in a hard, smooth, and round plastic tip. The device is directed the esophagus, are diffi cult to intubate around, owing to their through the vocal cords and into the trachea to serve as a large size and rigidity. Furthermore, caustic ingestions and guide for an endotracheal tube. The distal end is designed to known esophageal trauma or disease are contraindications minimize the chance of trauma to the larynx. Furthermore, the to use of these devices. Finally, they are considerably more small plastic “button” at the end “clicks” as it passes over tra- expensive than standard endotracheal tubes. cheal rings, giving the user feedback about placement. Once Both devices are intended for esophageal placement, the device has been placed, the endotracheal tube is threaded which occurs approximately 90% to 99% of the time. In the over the proximal end and advanced into the trachea. It has esophageal position, the distal cuff seals the esophagus while been shown to improve intubation rates in diffi cult airway the proximal cuff seals the hypopharynx. The proximal lumen situations.35–37 ventilates through a number of small holes between these There are multiple variants on the elastic gum bou- two cuffs. Since the opening to the larynx lies between these gie including plastic bougies,38 large-diameter feeding cuffs, ventilatory gasses passing through the proximal lumen tubes, and endotracheal tube exchanges. This last class can only go into the larynx and subsequently to the lungs. is of interest because some manufacturers make devices There are some limitations to the esophageal placement. Most importantly, epiglottic, perilaryngeal, and laryngeal injury or deformity (burns, trauma, edema, etc.) can prevent effective ventilation. Furthermore, respiratory secretions and bleeding between the two cuffs will be aspirated. Finally, medication administration and deep suctioning of the lungs are not pos- sible with esophageal placement. It is possible to obtain endotracheal placement of the Combitube. Anecdotally, increased rates of tracheal place- ment occur with well-performed cricoid pressure. When the devices are placed in the trachea, the distal cuff serves to seal the trachea (like the cuff of an endotracheal tube) while the proximal cuff helps stabilize the device. Ventilation is per- formed through the distal lumen that opens at the end of the tube, distal to |
the smaller cuff. Tracheal placement allows the device to function as an endotracheal tube and all procedures and medications normally performed with an endotracheal tube can be performed with the Combitube. In contrast, the Figure 23-19 Elastic gum bougie. Intubating Airway Management 435 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. through which a patient can be ventilated. All of these be placed in the endotracheal tube with the distal end of the devices are used similarly to the elastic gum bougie. There stylet 1 to 2 cm inside the distal end of the endotracheal tube. is no preparation of the devices other than to remove them The stylet is then bent into a “J” and the whole device placed from their packaging. If a disposable tube exchanger is aside for use. packaged in a bent-in-half position, the bend should be straightened as this will improve control of the device and Surgical Airways help thread the tube. One of the other advantages of the trachea’s close proximity to the anterior neck is that surgical airway management can Lighted Stylettes/Translaryngeal be achieved rapidly and effectively. There are three common Illumination Intubation variants on the technique. The fi rst is the classical surgical Due to the close proximity of the trachea to the anterior sur- cricothyroidotomy, a surgical procedure to gain entry to the face of the neck, it is possible to visualize light on the ante- trachea through the anterior neck. The other two techniques rior neck if a bright light source is placed on the trachea. are the needle and percutaneous cricothyrotomy techniques. Lighted stylettes (Figure 23-20) are, essentially, malleable Many manufacturers produce percutaneous cricothyro- stylettes with a bright light source at the distal end and a tomy kits that enable the placement of a single lumen tube power source at the proximal end. When placed in the tra- either similar to a large IV catheter or to a tracheostomy chea, a bright, well-circumscribed light is seen in the midline tube. The preparation and use of these kits is highly specifi c of the trachea. Placement in either pyriform fossa results in to the manufacturer and will only be discussed in general a light off the midline while esophageal placement results in terms. It is important to note that a surgical airway should be a diffuse, dim glow. performed only if that patient cannot be intubated, a rescue There are advantages and disadvantages to the use of device cannot be placed, and the patient cannot be ventilated lighted stylettes. Although the lighted stylettes were designed with standard face-mask techniques. The only exception to for use as adjuncts to standard orotracheal intubation,39 sub- the last requirement is if a patient can be ventilated with a sequent work has demonstrated their effi cacy as an alter- face-mask technique but the situation (prolonged transport, native to laryngoscopic intubation.40,41 Lighted stylettes can diffi cult extrication, or circumstances that would make surgi- be placed while the Paramedic is positioned either above a cal airway placement diffi cult at a later time) requires a more patient’s head or while the Paramedic is positioned along- secure airway. side the patient. They minimize C-spine movement and Opening a true or classical surgical airway is a relatively are therefore excellent devices for management of trauma simple process that involves the identifi cation of the crico- airways. thyroid membrane, cutting a hole through the cricothyroid There are a few disadvantages to the use of lighted membrane, and placing an endotracheal tube or cuffed tra- stylettes. If a patient has a very large neck, it may be impos- cheostomy through that hole. The process has been used suc- sible to differentiate between esophageal and tracheal cessfully in a number of prehospital systems and provides an placement. Bright lighting or sunlight may make visualiza- effective method of obtaining airway control when standard tion of the neck on the anterior neck diffi cult. Finally, there orotracheal intubation and rescue device utilization have is some evidence that lighted stylettes may cause laryngeal failed.43 There are complications associated with the proce- injury.42 dure. These include bleeding, carotid artery and jugular vein The lighted stylet should be removed from its package. injury, thyroid injury, accidental tracheostomy, pneumotho- Preparation for use is dependent on the manufacturer, but rax, mediastinal intubation, and esophageal perforation and there are some universal preparations. The device should be intubation.44 The procedure is contraindicated in patients turned on to test the batteries and the stylet portion should under the age of 12, with needle cricothyroidotomy being the procedure of choice for these patients, and in patients without recognizable anatomic landmarks. Extreme caution is needed in patients with neck injuries; if a hematoma has formed from a vascular injury, accidental decompression of the hematoma can make airway and bleeding control impos- sible. The hematoma may also obscure landmarks or devi- ate the trachea to one side, increasing the diffi culty of the procedure. Little equipment is needed for a surgical airway. A scalpel, a tracheal hook, and a 6.0 or 6.5 endotracheal tube or tracheostomy tube are all that are needed. The endotra- cheal tube should be prepared as described previously and the scalpel and hemostats should be removed from their Figure 23-20 Lighted stylet. packaging. 436 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Needle cricothyrotomy, also known as translaryngeal prepare for a needle cricothyrotomy, the IV catheter should cannula ventilation and/or transtracheal jet ventilation be removed from its packaging and attached to the syringe. (TTJV)—ventilation of the lungs using special high-pressure This will not work with safety catheters. If a safety cath- devices—is a commonly taught and performed technique for eter is being used, the syringe is not used. The TTJV device emergent oxygenation.45 In this technique, a large bore IV should be attached to the oxygen regulator if it is not already. catheter (12 to 16 gauge) is placed through the cricothyroid The oxygen should then be turned on and the device acti- membrane and a high pressure (50 PSI) oxygen source deliv- vated to assure that the control valve works properly and does ers oxygen to the lungs. As with the other surgical techniques, not stick. translaryngeal cannula ventilation is only indicated if less There are a number of different manufacturers of percu- invasive techniques have failed. taneous cricothyrotomy kits. Each device and technique has There are some important contraindications to this tech- advantages and disadvantages, so it is important to obtain nique. The equipment and technique rely on high pressure samples of each device and test them before adopting any to move a large volume of oxygen through a small device. specifi c device. Many have multiple parts that are easily lost Exhaust valves are not built into the device and therefore all in the uncontrolled prehospital environment. Others require exhalation must occur through the patient’s own upper airway. fi ne motor dexterity to utilize. If the patient has a complete airway obstruction (inspiratory It is best to choose a device that is simple to use, has a and expiratory), high-pressure ventilation without escape of minimal number of parts that can be lost, and is easily stored gasses results in overpressurization injuries. and adapted to equipment already being used. Past teaching stated that this technique provides only a method of oxygenation and that there is no ventilation (carbon dioxide exhalation). However, a number of animal studies46,47 Patient Preparation and human studies48,49 have demonstrated normal, and even Once the decision to intubate has been made and the appro- low (overventilation), carbon dioxide levels if a fl ow rate of priate equipment has been prepared, the next step is to pre- 1,600 mL/sec (the fl ow rate through a 21 gauge catheter with pare the patient for intubation. Preparing the patient occurs a 50 PSI oxygen source) is used. Therefore, transtracheal jet in three ways: assessment of the patient, positioning of the ventilation with appropriate equipment is a valid method of patient, and, if needed, medication administration. oxygenating and ventilating a patient in whom an airway can- It is important to assess all patients before undertaking not otherwise be established. an intubation (or any airway management). There are a num- The equipment for needle cricothyrotomy consists of a ber of anatomic features that may suggest diffi culty will be large bore IV catheter (12 to 16 gauge), a 5 to 10 cc syringe, encountered during the airway management. Although the and a high pressure (50 PSI) oxygen source. Although various presence or absence of the characteristics will not change methods of ventilating through a needle catheter have been the need to manage the airway, they do infl uence decisions described, including syringe to BVM adapters44 and oxygen such as the use of medications for sedation and paralysis as tubing with a small hole cut in the side to control “on” and well as optimal patient positioning and equipment selection. “off ”,45 many commercial TTJV devices are available and are Therefore, the Paramedic should assess all patients before the best choice for this technique (Figure 23-21). attempting airway management. These devices attach to the high pressure output ports of Several studies have looked at the problem of anticipated standard oxygen regulators either by screwing onto the regu- and unanticipated diffi cult airways.50–54 Several factors have lator or via a previously attached quick-connect device. To been identifi ed as predictors for diffi cult airway management and/or diffi cult tracheal intubation (Table 23-2). Although some of these characteristics cannot be eas- ily identifi ed before the intubation (i.e., a fl oppy epiglottis), others can and have led to mnemonics and memory aids for anticipating a diffi cult airway. Two of the most useful are the 3-3-2 rule and the LEMON law, both developed as part of the National Emergency Airway Course.55 The 3-3-2 rule is a simple method for rapidly evaluat- ing a patient’s anatomy. In an “easy” airway, the Paramedic should be able to: ■ Place three fi ngers between the tip of the chin and the hyoid bone ■ Place three fi ngers between the upper and lower teeth at the maximal mouth opening ■ Place two fi ngers between the thyroid notch and the Figure 23-21 Transtracheal jet ventilation. fl oor of the mouth Intubating Airway Management 437 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Table 23-2 Diffi cult Intubation Conditions The LEMON law similarly provides a rapid mnemonic for evaluating a patient. The elements of the LEMON law • Male gender are to: • Obesity ■ L—Look externally for anything that will hinder • Age between 40 to 59 ventilation or intubation • Decreased mouth opening ■ E—Evaluate the 3-3-2 rule to assess the airway anatomy • Shortened thyromental distance ■ M—Mallampati classifi cation (Figure 23-22) • Poor visualization of the hypopharynx ■ O—Obstruction, either new or chronic, should be • Limited neck extension evaluated • Receding chin ■ N—Neck mobility should be determined if not • Abnormal dentition contraindicated (contraindicated in suspected C-spine • Large tongue injury) • Beards These two rules, if applied to every patient, should help • Supraglottic mass to predict a diffi cult airway and help the Paramedic to pre- • Floppy epiglottis pare accordingly. |
Of these guidelines, the Mallampati score • Trauma patient is the most diffi cult to determine in the fi eld. The score is most accurate when the patient is assessed in a seated posi- • Pregnant patient tion, opens her mouth, and sticks out her tongue. This is • Mallampati score > 2 (Figure 23-22) not practical for most patients requiring prehospital airway management. Positioning the patient is one of the most critical steps in improving the rates of successful fi rst intubation attempts. Although every intubation attempt should be a best attempt, in the emergent setting of prehospital intubations the fi rst attempt is often made from the position in which a patient is found. Unfortunately, each attempt at intubation increases edema and bleeding in the airway, making subsequent attempts more diffi cult. Therefore, although the temptation exists to “just get a tube in,” the reality is that without forethought, a diffi cult airway can be made into an impossible-to-intubate- or-ventilate airway. Although intrinsic issues such as suspected cervical spine trauma may preclude optimal patient positioning, in most other cases some simple interventions can properly position a patient for intubation. The ideal position, described by Chevalier Jackson in 1913, is the “sniffi ng” position56 Class l: soft palate, uvula, Class ll: soft palate, fauces, pillars visible uvula, fauces visible (Figure 23-23). No difficulty No difficulty Class lll: soft palate, Class lV: hard palate base of uvula visible only visible Moderate difficulty Severe difficulty Figure 23-22 Mallampati classifi cation. Figure 23-23 Sniffi ng position. 438 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Bannister and MacBeth, in 1944, clarifi ed the posi- require less force for glottic visualization.61 The use of this tion as one in which the oral axis, the pharyngeal axis, and position is contraindicated in suspected cervical spine or the laryngeal axis are all aligned through fl exion of the back injuries. neck to 30 degrees and extension of the head on the atlanto- In trauma patients, the issue of positioning becomes occipital joint.57 more diffi cult. Clearly, neck fl exion and head extension are Although there is some research to suggest that simple contraindicated. However, anterior displacement of the jaw head extension, which is obtained in a “head-tilt, chin-lift” via a modifi ed jaw thrust partially mimics head extension. In maneuver (Figure 23-24), may be as effective as the sniffi ng addition, proper application of backward, upward, and right- position in providing a good laryngoscopic view,58 this has ward pressure (the BURP technique discussed later in this not been validated.59 Therefore, for anatomical and theoreti- chapter) may improve the view. Finally, having an assistant cal reasons, the sniffi ng position is considered to be the posi- open the cervical collar and provide in-line stabilization from tion of choice for patient positioning during intubation.60 the inferior direction will allow greater mobility of the jaw. At the time of intubation, most patients will already be All of these techniques substitute for ideal positioning in the in the “head-tilt, chin-lift position” commonly used for face- trauma patient. mask ventilation. This position places the head in extension The fi nal step in patient preparation is the appropriate use along the atlanto-occipital joints, bringing the pharyngeal of sedatives and paralytic agents. A full discussion of these and laryngeal axes—but not the oral axis—into alignment. agents, as well as the techniques of medication facilitated and By lifting the head anteriorly approximately 7 cm, the neck is rapid sequence intubation, can be found in Chapter 24. fl exed to 30 degrees and the oral, pharyngeal, and laryngeal axes are brought into alignment. This alignment allows for Oral Endotracheal Intubation the best view during intubation. It is important to note that it may be diffi cult to obtain Once the equipment and patient have been prepared, it is time neck fl exion in obese patients or patients with very short to perform the intubation. The vast majority of intubations are necks. Sitting these patients upright can “create” a neck performed via the oral route and it is therefore likely to be the and change a diffi cult intubation into a relatively easy intu- fi rst technique the Paramedic performs on a given patient. The bation. This position can be obtained by sitting the patient process can be broken down into four important steps: visualiz- upright on a chair, packing multiple blankets underneath his ing the vocal cords, passing the endotracheal tube, confi rming shoulders and back, or positioning the stretcher at a 50 to endotracheal tube placement, and securing the endotracheal 70 degree angle and placing a folded blanket or towel behind tube. Mastery of each of these steps increases the chances of a the head. successful intubation. The head elevated laryngoscopic position (HELP) is It is important to note that endotracheal intubation is a a patient position that places the head in extension along team activity. Although Paramedics often fi nd themselves the atlanto-occipital joints, bringing the pharyngeal, laryn- with minimal assistance, it is important that all available geal, and oral axes into alignment using an elevation pillow. resources be used effectively. There should be at least two It can also be used in patients who are unable to lay fl at team members performing the intubation—the Paramedic (i.e., CHF patients or morbidly obese patients) or to help and an assistant. It is the assistant’s job to check and assemble clear secretions. In addition, patients in the HELP position equipment, assist in preparing the patient, and then provide extra hands during the intubation. The two common tasks of the assistant are handing equipment to the intubator and providing digital pressure to the upper airway during the intubation. There are three ways in which the assistant can provide digital airway pressure. The fi rst technique, cricoid pressure maneuver, applies 10 pounds of backward pressure on the cri- coid ring. This pressure minimizes the risk of passive regurgi- tation. Unfortunately, cricoid pressure maneuver may worsen the laryngoscopic view of the tracheal opening. In addition, often the pressure is mistakenly applied to the thyroid carti- lage. Thyroid pressure not only does not seal the esophagus (the thyroid cartilage is an incomplete ring posteriorly) but it does not improve the laryngoscopic view; in fact, it often tips the vocal cords even more anteriorly, making them more diffi cult to see. A superior method to improve laryngoscopic view is backward, upward, and rightward pressure (the BURP tech- Figure 23-24 Head-tilt, chin-lift position. nique62). Finally, if the Paramedic is performing two-handed Intubating Airway Management 439 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. laryngoscopy or external laryngeal manipulation, the assis- the epiglottis anteriorly and reveals the vocal cords. It is also tant may be asked to hold the larynx in the position that pro- possible for the tip of the Macintosh blade to capture the epi- vides the Paramedic the best view of the vocal cords. glottis in the same manner as the Miller blade. If this happens and the vocal cords are visualized, do not move the blade. If, Visualizing the Vocal Cords however, the blade obscures the view of the vocal cords then it needs to be repositioned in the vallecula. To visualize the vocal cords, the Paramedic must use the laryn- The Miller blade is designed to pin the epiglottis against goscope to provide lighting and a direct line of sight through the base of the tongue anteriorly and provide a straight-on the mouth to the larynx. Although there are differences in view of the vocal cords. The Paramedic should therefore see technique between the two most commonly used blades—the the tip of the blade slide posteriorly to the epiglottis and, when Macintosh (curved) and Miller (straight) blade—there are the blade is lifted anteriorly and inferiorly, the tip should lift many similarities as well. up the epiglottis to reveal the vocal cords. It is important to The patient’s mouth must fi rst be opened. If the patient note that since the Miller blade provides less displacement of was already receiving face-mask ventilation, an oropharyn- the tongue, the view is more likely to be down the right side geal airway will probably already be in place. If this is the of the mouth as opposed to down the midline, as is the case case, it should be removed while the head and jaw are held with a Macintosh blade. still to maintain an open airway. If the mouth has not already Obtaining a view of the vocal cords is often the most dif- been opened, a crossed fi nger technique using the thumb on fi cult part of the intubation. Once the Paramedic has begun the lower teeth and the index fi nger on the upper teeth should the intubation, it is important to assess the degree of diffi culty be used. Once the airway is opened, the laryngoscope, held in seeing the cords. Although a simple “easy” or “diffi cult” in the left hand, is inserted in the right side of the mouth, lat- system can be used, there are quantitative measures. The most eral to the tongue. The laryngoscope should be held with the commonly used is the Cormack-Lehane grading system tips of the fi ngers and the thumb as the procedure is one of (Figure 23-25). skill and fi nesse, not brute force. The laryngoscope is swept The system grades the view of the glottic opening by how to the midline. In the case of the Macintosh blade, the large much is occluded by the tongue—Grade I is a clear view of fl ange should completely displace the tongue to the left and the entire glottic opening whereas IV is visualization of the the blade can be moved slightly past the midline. The Miller tongue or soft palate only. Proper patient position and exter- blade will not completely displace the tongue and should nal laryngeal manipulation, described later, can improve the therefore be swept no further than the midline. Once this has view by one to two grades. been done, the Paramedic should have a clear view of the oropharynx. The tip of the laryngoscope is advanced under direct visualization. Once the epiglottis is identifi ed, the blade tip is appropriately placed and the whole laryngoscope is pushed anteriorly and laterally, essentially lifting the man- dible away from the pharynx and larynx at a 45-degree angle to the body. The direction of movement should be like aim- ing for the junction of the ceiling and wall on the opposite side of the room. This anterior and lateral lifting prevents the Paramedic from tilting the handle superiorly and damaging the upper teeth. At this point, the laryngeal structures should be visible. The paraglossal approach to intubation involves insert- ing the entire length of the laryngoscope blade blindly into Grade 1 Grade 3 the esophagus and then slowly withdrawing the blade under direct visualization.63,64 When using this method, both curved and straight blades are used to capture and lift the epiglottis. Although there is no evidence to support this method or the methods described in the following text, there is anecdotal evidence that this method can be performed consistently and is less traumatic than other methods. The tip of the Macintosh blade is designed to fi t into the vallecula. Therefore, the Paramedic should see the tip of the blade slip between the tongue anteriorly and the epiglottis Grade 2 Grade 4 posteriorly. When the blade is lifted anteriorly and laterally, the tip pulls on the hyoepiglottic ligament, which in turn pulls Figure 23-25 Cormack-Lehane grading system. 440 |
Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Aside from patient positioning there are several techniques the Paramedic should attempt to move it with Magill forceps that can be performed once the laryngoscope is in place. Two (Figure 23-27). The attempts should be made under direct of the most effective are external laryngeal manipulation visualization to avoid pushing the foreign body further into (“two-handed laryngoscopy”) and retraction of the right cor- the airway. If the foreign body is subglottic and cannot be ner of the mouth. These two techniques improve visualization grasped with the Magill forceps, it should be pushed into a of the glottic opening. External laryngeal manipulation has mainstem bronchus with an endotracheal tube and the tube been well described in the ear-nose-and-throat65,66 and airway withdrawn to above the carina to allow at least one lung to be management literature.67, 68 In this technique, the Paramedic ventilated. performs direct laryngoscopy with his left hand while manip- ulating the larynx with his right hand (Figure 23-26). Once he has an improved view of the glottic opening, the Paramedic Street Smart has an assistant take over the external laryngeal manipula- tion, holding the larynx absolutely still. Alternately, the assistant may place his hand on the cricoid The tips of the Magill forceps, due to their shape, cartilage while the Paramedic grasps and guides the assistant’s grip best on smaller and irregularly shaped objects. hand with his right hand. In this variant, once the proper posi- Large, smooth objects are almost impossible to grasp tioning is attained, the assistant already has his hand in the cor- and may require pinning the object between the rect position. External laryngeal manipulation greatly improves successful glottic visualization. Magill forceps and the suction catheter to lift it. Often it is diffi cult to see past the lips. Having an assistant hook the right corner of the mouth with a fi nger and retract the corner of the mouth may provide a suffi cient opening to Ambient light may also make visualization of the glot- allow visualization of the glottic opening. It is important that tis diffi cult. Very bright light can “wash out” the structures the assistant’s fi nger not be placed between the teeth in the and cause refl ections off of secretions that make landmark event the patient has a seizure, suffers a muscle spasm, or identifi cation impossible. Turning lights down or off while decides to bite. This technique is particularly useful in the inside a building or in the back of an ambulance can make patient with large cheeks, lips, or a large, diffi cult-to-control visualization much easier. If it is impossible to decrease the tongue. ambient light, placing a large sheet or blanket—or fl ipping a Foreign bodies and body fl uids such as mucus or vomit coat—over the Paramedic’s and patient’s heads should prove can make visualization of the glottic opening diffi cult. If suc- adequate shade to allow better visualization. tioning is required, a rigid suction catheter should be used. No more than 15 seconds of suction should be applied and Passing the Endotracheal Tube the suctioning should be performed under direct laryngos- Once the glottis has been visualized, the next step is pass- copy. By suctioning with visualization, airway and soft-tissue ing the endotracheal tube through the vocal cords. The tube trauma is minimized. If a large foreign body is encountered, should either be in a location where the Paramedic can fi nd Figure 23-26 External laryngeal manipulation. Figure 23-27 Magill forceps. Intubating Airway Management 441 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. it without looking away from the vocal cords, or the assistant should hand the tube to the Paramedic, since looking away increases the risk of movement and the need to revisualize the glottic opening. The tube is grasped in the right hand and introduced from the right side of the mouth. It is often easiest to place the tube in the mouth sideways with the inside of the curve toward the right side of the mouth so the Paramedic can watch the tip move toward the cords without the rest of the tube obstructing his view. Once the tip of the tube is at the level of the vocal cords, the tube should be rotated counterclockwise 90 degrees so that the curve of the tube is in the same direction as the curve of the airway. The tube is advanced through the cords under direct visualization until the cuff is 2 to 3 cm below the cords or, in pediatrics, the cords lie between the two black rings. (a) If the cords are closed, as occurs with laryngospasm, or only partially open, it will be diffi cult to advance the tube. In the case of laryngospasm, gentle pressure of the lip of the tube bevel between the cords may cause them to relax suf- fi ciently to pass the tube. The Paramedic should not “force” the tube or the stylet between the cords. If this does not work, alternative approaches (e.g., a surgical airway) may be nec- essary. If the cords are partially open, placing the tip of the tube into the space between the cords and applying gentle pressure may allow the tube to advance. Again, the Paramedic should not force the tube. Gently turning the tube clockwise and counterclockwise may also allow it to advance. Finally, having the assistant remove the stylet while the tip of the tube gently presses against the vocal cords may give the tube enough fl exibility to advance. (b) Once the endotracheal tube has passed between the cords, the Paramedic should look at the depth of the tube Figure 23-28 (a) Auscultation of epigastric and as measured by the centimeter marking at the lip line and (b) breath sounds. not let go of the tube until it has been secured in place. The depth will typically be 22 to 24 cm in the average sized adult patient. However, if the cuff was advanced 2 cm below the Equal sounds heard bilaterally strongly suggest proper vocal cords, then the endotracheal tube is in the correct posi- tube placement. Due to the anatomy of the carina and the tion. The stylet should be removed and the cuff infl ated. The mainstem bronchi (see Chapter 20), an endotracheal tube that tube position should be confi rmed and the tube secured. At is inserted too deeply will more often advance into the right this time, the Paramedic may release the tube. mainstem bronchus. If this occurs, lung sounds will be heard on the right but will be diminished or absent on the left. If this Confi rming Endotracheal occurs, the cuff of the endotracheal tube should be defl ated and the tube withdrawn 1 to 2 cm. After tube movement, the Tube Placement cuff should be reinfl ated and the lungs reauscultated. This pro- Once the tube has been placed, a bag-mask assembly device cedure is repeated until equal breath sounds are heard or the or automatic transport ventilator should be attached to venti- tube is pulled from the larynx. The second situation implies left late the patient. Ideally, an end-tidal carbon dioxide detector or lung pathology or a pneumothorax, depending on the clinical measuring device should be in-line from the fi rst ventilation. context. It is important to recognize that left mainstem intuba- When the fi rst breath is delivered, the epigastrium should be tions can occur and should be treated in the same manner as auscultated (Figure 23-28a). Loud noises over the epigastrium right mainstem intubations. with abdominal distention and no chest movement strongly Once the tube position is assessed by auscultation, the suggest esophageal placement. The tube should be removed Paramedic should assess placement using end-tidal carbon immediately while cricoid pressure is maintained. If no sounds dioxide measurement. Although ETCO measurement does 2 are heard at the epigastrium, auscultation at the mid-axillary have some limitations as previously described, it is considered lines at the level of the nipple line should be performed bilater- by many to be the gold standard of endotracheal tube place- ally (Figure 23-28b). ment assessment in the patient with spontaneous circulation. 442 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. If a disposable colorimetric capnometer is used, the Suction must be prepared. The misplaced tube is removed appropriate size (adult or pediatric) should be selected carefully. The patient is ventilated until the hypoxia resolves and placed between the ventilation device and the 15 mm while the tube is re-prepared or a second tube is prepared. adapter on the endotracheal tube. Six breaths should be Further steps to be taken before the repeat intubation attempt delivered to wash out carbon dioxide from the stomach in are discussed in the following text. case an esophageal placement has occurred. The device will A mnemonic that can help the Paramedic remember the originally be purple. If the tube is properly placed, the color causes of problem intubations is DOPE. The D in dope stands will change to yellow with each breath and fade back to a for displaced endotracheal tube; the O stands for obstructions yellow-purple color during inspiration. If the color change of the endotracheal tube, such as a mucous plug; the P sug- is intermediate between purple and yellow, tube placement gests the possibility of a pneumothorax; and the last letter, E, must be confi rmed by other methods. indicates equipment failure. If a continuous monitoring device is used, the sampler adapter is attached between the ventilation device and the Securing the Endotracheal Tube 15 mm adapter on the endotracheal tube. If a mainstream Once endotracheal tube position is confi rmed, the tube must device is being used, the infrared device must also be attached. be secured to prevent movement. The most common way to The Paramedic should watch the numerical readings (capnom- do this is through the use of a commercial or homemade tube etry) or the waveform (capnography). Although readings of tie. If a commercial device is used, be sure to confi rm endo- 30 to 40 are considered normal, the more important informa- tracheal tube depth before placing the device as many pre- tion is that the numbers or the wave rises and falls appropriately vent visualization of the tube at the lips. If a homemade tie is with ventilation, that the waveforms are consistent in shape, used, the Paramedic must confi rm that the tube cannot slip or and that no abrupt changes occur. It is important to realize move once the tie is complete. Taping the endotracheal tube that while different waveforms have different implications, the to the face, although appropriate in the operating room, is not presence or absence of a waveform (or consistent numerical appropriate in the prehospital setting due to the amount of trends with a capnometer) is the most valuable piece of infor- patient movement that will occur. mation for confi rming tube placement. It is also important to There is growing evidence that many endotracheal tubes note that end-tidal carbon dioxide detectors will not assess for found in the esophagus or the hypopharynx once the patient mainstem intubation or for hypopharyngeal placement |
of the reaches the emergency department are not misplaced tubes, endotracheal tube. but rather are displaced tubes. That is, the tube was origi- The limitations of end-tidal carbon dioxide detectors in nally in the trachea, but during patient movement it became patients without spontaneous circulation are clear: a patient displaced. Therefore, it is important that the tube position be who is not producing carbon dioxide nor circulating it to the assessed after each move. In addition, the biggest determinant lungs will not exhale carbon dioxide. Therefore, using an of tube movement is neck fl exion and extension. It has been esophageal detector device for confi rmation of endotracheal demonstrated that placement of a cervical collar and cervi- tube placement is appropriate. If a squeeze bulb is used, it cal immobilization device (head blocks and backboard) on should be squeezed and attached to the 15 mm endotracheal all intubated patients decreased the rates of displaced tubes.69 tube adapter. Immediate (less than 4 seconds) silent infl ation Therefore, all intubated medical and trauma patients should confi rms tracheal placement while noisy, fl atus-like sound or have a cervical collar placed and be immobilized on a long delayed infl ation suggest esophageal intubation. If a syringe- spine board, if possible (Skill 23–1 and Figure 23-29). type device is used, 40 mL of air in adults and 10 mL of air in children older than 2, that is withdrawn without resistance, confi rms tracheal placement. Resistance or inability to with- draw air suggests esophageal placement. It is important that the syringe plunger be all the way down and that the bulb be squeezed before attachment to the endotracheal tube. If an esophageal intubation occurs, the Paramedic must make a choice. If the patient is still well-oxygenated, a sec- ond intubation attempt can be made with the esophageal tube in place. This method has the advantage of the esophagus already being occupied by the misplaced endotracheal tube. The second endotracheal tube is placed in the only remain- ing opening, the larynx. The disadvantage of this technique is that it can be diffi cult to intubate around a tube that is already in place. Additionally, the patient is at increased risk for hypoxia. If the patient is hypoxic or it is impossible to intubate Figure 23-29 Intubated patient immobilized to around the esophageal tube, several steps must be taken. prevent dislodgement of the endotracheal tube. Intubating Airway Management 443 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. For a step-by-step demonstration of becoming detached from the adapter and the patient aspirat- Orotracheal Intubation, please refer to Skill 23-1 ing the endotracheal tube. on page 455. Confi rming Placement The endotracheal tube placement is confi rmed in the same Nasotracheal Intubation manner as in an orotracheal intubation. Lung sounds should If the patient is breathing, the Paramedic has the choice of be auscultated, an esophageal intubation detection device performing a nasotracheal intubation. Nasotracheal intuba- should be attached, and end-tidal carbon dioxide should be tion is particularly well suited for patients who, due to their measured. One important difference is that patients who are disease process (e.g., COPD exacerbation, CHF), are likely to nasally intubated are breathing spontaneously. Therefore, experience rapid decompensation if they lay fl at. In addition, auscultation may be misleading. Additionally, if the patient’s patients who are diffi cult to access (e.g., entrapped patients) status does not improve after the intubation, reassessment for may be easier to nasotracheally intubate than to orotracheally tube placement is necessary as the patient may appear to be intubate. Contraindications to nasotracheal intubation include tracheally intubated but in fact be esophageally intubated. apnea, evidence of basilar skull fracture, or inability to pass the tube through a nare (e.g., from a deviated septum). Securing the Endotracheal Tube Most commercial devices designed for securing an oral endo- Patient Preparation tracheal tube are not suited for securing nasal intubations. If the decision is made to nasotracheally intubate a patient, Folded tape, ties, or IV tubing is much better suited for secur- the patient must be prepared. The optimal position is the ing the tube. The tie should go the whole way around the head “sniffi ng position” with the patient sitting upright. The neck to provide maximum security. Again, the patient’s head and is fl exed and the head slightly extended across the atlanto- neck should be secured with a cervical collar and cervical occipital joint. The nose must be prepared with anesthesia and immobilization device if the patient is able to tolerate these lubricant. The patient should be asked for a history of nasal devices (Skill 23-2). fracture, surgery, or septal deviation. Although the larger nos- For a step-by-step demonstration of tril is most likely to provide the greatest success, once the Nasotracheal Intubation, please refer to Skill 23-2 nose is anesthetized, internal palpation with the small fi nger on page 456. may provide a good deal of information about obstructions and anatomy. Once the patient is properly positioned, the nose should be premedicated with a mixture of a nasal decongestant con- Street Smart taining neosynephrine and viscous lidocaine or lidocaine jelly (if the patient is not allergic to lidocaine). If possible, the The phrase “the hose follows the nose” describes the patient should inhale as these medications are administered to maximize the area reached. Use of the nasal decongestant behavior of an endotracheal tube. When the neck is decreases the risk of bleeding while the topical anesthetic extended (nose moves up), the endotracheal tube is improves patient comfort. Placing a nasopharyngeal airway displaced superiorly. When the neck is fl exed (nose coated with lidocaine jelly also helps anesthetize the mucosa and prepares the patient for the sensation of a device in moves “down”) the ETT is displaced inferiorly. This the nose. rule predicts the effects of head movement. Intubation If possible, an endotracheal tube designed for nasal intuba- tion should be used. The tube should be placed in the most Failed Intubation patent nare with the tip of the tube parallel to the fl oor of the If the intubation fails, the Paramedic must perform a rapid nose. The tube is advanced until breath sounds are audible assessment of why the failure occurred. If the fi rst attempt through the tube. A Beck Airway Airfl ow Monitor (BAAM) failed, performing the exact same techniques with the should be used, if available. This device changes the sound exact same equipment almost guarantees a second failure. of airfl ow to a whistle. The tube is rotated until breath sounds Therefore, it is important that the Paramedic understand or the whistle is at its loudest. The tube is then advanced why the failure occurred and what remedies will correct through the cords during inspiration. The patient may cough the failure. as the endotracheal tube passes through the cords; the The assessment of a failed intubation should focus on oper- Paramedic should continue to advance the tube. The tube ator failure, patient preparation failure, and equipment failure should be advanced until approximately 2 cm protrude from or incorrect selection. Operator failure is an honest assessment the nose. If the tube is advanced to the hub, it is at risk for of the Paramedic’s ability to perform the intubation. The best 444 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Paramedics are the ones who recognize when they are faced with an airway that is beyond their abilities to manage. This recognition in no way implies that the Paramedic is incompe- tent. Some patients’ anatomy is not compatible with oral or nasal endotracheal intubation without adjunctive devices such as intubating LMAs or fi beroptic devices. If the Paramedic is sure that ability is not the issue, then the next step is to assess patient positioning failure. Once the laryngoscope is in the patient’s mouth, it is often possible to recognize that a different position would allow for optimal oral, pharyngeal, and laryngeal axis align- ment. If this is the case, repositioning the patient, adding or subtracting padding behind the head, or changing to a HELP position are all acceptable actions. Often times the fi rst intu- bation attempt is made in an “as found” position. This should be corrected for any subsequent intubation attempts. The fi nal area of assessment is of equipment. The most basic question is whether or not the equipment is functioning correctly. A burnt-out laryngoscope bulb makes airway visu- alization impossible. The second question is the appropriate- ness of the equipment. If the incorrect blade or blade size has been chosen, an appropriate substitution should be made. The fi nal decision is the appropriateness of the technique and adjunctive devices. There are several intubation techniques and adjuncts that can be used to facilitate endotracheal intubation on the Figure 23-30 Digital intubation. second and third intubation attempts. These include digital intubation, use of the elastic gum bougie, translaryngeal illu- mination, and use of a fi beroptic stylet or bronchoscope. It is important to note that the Paramedic should not use these For a step-by-step demonstration of Digital Intubation, techniques for the fi rst time during an emergency situation. please refer to Skill 23-3 on page 458. Instead, they should be practiced in controlled circumstances, for example in an OR or simulation lab. The Elastic Gum Bougie Digital Intubation The elastic gum bougie is a useful adjunctive device for the management of the diffi cult airway. It is placed under direct Digital intubation is an endotracheal intubation technique visualization with a laryngoscope. It is most useful when that uses the Paramedic’s hand to identify laryngeal struc- the only anatomy that can be visualized are the posterior tures and to guide tube placement. It should only be used arytenoids. The tip of the bougie is advanced anterior to the for patients who are at no risk of biting the Paramedic. Like posterior arytenoids until the tip “clicks” along the tracheal nasal intubation, it is a blind technique. Therefore, multiple rings. An endotracheal tube is threaded over the external end techniques of tube placement confi rmation are critical. One of the bougie and advanced into the trachea. The external end advantage of digital intubation is that the patient’s head of the bougie should be stabilized to prevent it from becom- remains in a neutral position without movement. In addition, ing displaced. The cuff is infl ated and the gum bougie is with- digital intubation can be performed on a patient in a sitting drawn. The tube is confi rmed and secured in the usual fashion position and from below the head, which is useful for patients (Skill 23-4). for whom access to the head is limited. For a step-by-step demonstration of Elastic Gum The Paramedic prepares the endotracheal tube in the stan- Bougie, please refer to Skill 23-4 on page 459. dard manner. The patient’s tongue is grasped with gauze and retracted out of the mouth by an assistant. The Paramedic’s hand is then advanced to the posterior oropharynx. The index Translaryngeal Illumination fi nger is used to palpate and lift the epiglottis while the mid- Translaryngeal illumination, using a lighted stylet, takes dle fi nger palpates the arytenoid cartilages (Skill 23-3 and advantage of the larynx’s proximity to the anterior surface Figure 23-30). The dominant hand is used to advance the tube of the neck for endotracheal intubation. The patient should between the epiglottis and the arytenoids. Once the tube is in be placed into a neutral position for the intubation. If pos- place, it is confi rmed and secured in the standard manner. sible, the scene |
should be made as dark as possible. Placing a Intubating Airway Management 445 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. blanket over the Paramedic and the patient may make it pos- decreases the success of other methods of securing the air- sible to perform the technique during daylight conditions. way and of being able to face-mask ventilate the patient. Turn the stylet on and advance it into the midline of the phar- Continuing attempts could potentially lead to a completely ynx, following the mouth’s curvature. The stylet is advanced unmanageable airway. until a focal, bright midline glow is visible at the level of the The second reason for setting a limit to the number of larynx. It is advanced another 1 to 2 cm and then the stylet is airway attempts is that it drives the Paramedic to abandon removed. The cuff of the endotracheal tube is infl ated and the a technique (endotracheal intubation) that is not working. tube confi rmed and secured. By having a set limit on intubation attempts, the Paramedic must move on to other, more productive techniques. This limit prevents the “I’ll get it on the next attempt” syndrome Fiberoptic Stylettes/Bronchoscope that can only hinder patient care. Therefore, after three In some circumstances, obtaining a view from the distal failed intubations, the Paramedic should move on to other end of the endotracheal tube can improve the chances of techniques. successful intubation. Although expensive, these devices may turn an unobtainable airway into an obtainable one. It Supraglottic Airway Devices is unlikely that they will be commonly used in most EMS systems, but they may have a place in specialty systems. Once conventional endotracheal intubation has failed, the Two classes of devices—bronchoscopes (in which the tip next step is to use a supraglottic airway device. These devices can be controlled by the operator) and fi beroptic viewing provide a method of at least partially securing the airway in stylettes (in which the stylet is molded into shape before the the diffi cult-to-intubate patient. The three most commonly intubation but cannot be moved during the intubation)—are used devices, as described earlier, are the King LTS-D air- used. The second class of devices is less expensive. Both way, the laryngeal mask airway, and the esophageal-tracheal are limited in their utility if there is blood or vomit in the Combitube. airway; the view through the scope is rapidly degraded by these substances. King LTS-D Airway The devices should be prepared according to the manu- Prepare the patient as previously described for endotracheal facturer’s specifi cations. The endotracheal tube is loaded onto intubation, including preoxygenation, monitoring, and supine the scope and the viewing tip of the scope treated with antifog position. With the left hand, grasp the tongue and jaw and solution. If a fi beroptic viewing stylet is used, it should be lift toward the ceiling. With the right hand, insert the King molded into a hockey stick shape before insertion. The scope airway from the right side of the mouth and direct it toward and tube are advanced under direct visualization until the tip the oropharynx. As the King airway is advanced, rotate the of the scope passes through the cords. If a bronchoscope is airway counterclockwise as it seats in the proper position. used, the tip can be manipulated to direct the scope into the Advance the airway until the orogastric port is approximately larynx. The endotracheal tube is then advanced through the at the level of the front teeth. Infl ate the balloons and venti- cords, the scope is withdrawn, and the cuff is infl ated. Usual late the patient. Auscultate breath sounds while gently pulling methods of confi rming tube placement and securing the tube back on the airway until the sounds are the loudest. Secure are used. the King airway in position after confi rming placement Fiberoptic devices can also be used to confi rm endo- (Skill 23-5). tracheal tube placement in diffi cult intubations. Once For a step-by-step demonstration of King the endotracheal tube has been placed, the scope can be Airway Placement, please refer to Skill 23-5 passed through the tube under direct visualization. Once on page 461. the scope advances beyond the tip of the endotracheal tube, the Paramedic can identify the trachea by the presence of tracheal rings or the esophagus by the lack of rings and The Laryngeal Mask Airway the collapsing walls. Although other methods, such as The laryngeal mask airway transfers the seal of the face end-tidal carbon dioxide monitoring and the esophageal mask from the patient’s face to his larynx. The prepared intubation detection devices, are generally reliable, direct device, as previously described, has the cuff mask defl ated visualization of tracheal rings is another way of confi rming and the tip lubricated. The mask should be picked up with tube placement. the thumb in the space between the tube and the mask. The The Paramedic should make the most of each intu- mask is placed in the oropharynx with the tip against the bation attempt. He should make no more than three hard palate. It is advanced into the hypopharynx with gentle attempts to intubate the patient. There are two main rea- pressure from the thumb. The mask is pushed until resis- sons for establishing a clear limit to the number of intu- tance is met. If the appropriate-sized mask is used, it will bation attempts. The fi rst is that each intubation attempt sit with the tip in the proximal esophagus and automatically causes airway trauma and makes each subsequent intubation position the mask. The pilot balloon will indicate the correct attempt more diffi cult. In addition, each intubation attempt volume of infl ation for the mask. When the mask is infl ated, 446 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. the tube should “lift” slightly out of the mouth as it seals until it rests securely at its appropriate depth (depth markers (Figure 23-31). on the tube should be at the level of the teeth). If resistance Laryngeal mask airway placement is confi rmed by aus- is met, the device should not be forced. A small amount of cultation, end-tidal carbon dioxide measurement, and assess- cricoid pressure may increase the chances of a tracheal place- ment of patient status. The esophageal intubation detector ment, and should be avoided. device does not function with the LMA. Even when the epi- Once the Combitube has been inserted, the pharyngeal glottis is folded over, the LMA provides highly effective ven- cuff is infl ated fi rst with 100 cc of air. Then, the distal cuff tilation.70 The LMA is secured with the tube curved toward is infl ated with 10 to 15 cc. The patient is ventilated through the feet with a wrap of tape. the pharyngeal lumen. Chest rise and lung sounds indicate esophageal placement and ventilation is continued through The Esophageal-Tracheal Combitube this tube. If no lung sounds are appreciated and the chest The Combitube offers an effective method of securing the does not move, the patient is ventilated through the tracheal airway in either esophageal placement or tracheal placement. lumen; the patient should now have lung sounds and chest Once the equipment is prepared as previously described, rise (Figure 23-32). the jaw is grasped and lifted anteriorly with the thumb in Device placement is confi rmed with auscultation and the mouth and the fi ngers under the mandible. The device is end-tidal carbon dioxide monitoring. The esophageal intuba- inserted following the curvature of the oro- and hypopharynx tion device will not work on the pharyngeal lumens and has not been confi rmed as reliable for use on the tracheal lumens; it should therefore not be used. The patient’s status must be continuously monitored. Although the pharyngeal balloon contributes greatly to tube security, the device must still be secured with a tie and the patient should have a C-collar and cervical immobilization. Despite their ease of use, both devices do have compli- cations associated with them. Excessive force during inser- tion can cause tracheal and esophageal injury. The devices can become dislodged and misidentifi cation of tube posi- tion has been reported in some cases. Therefore, careful monitoring and frequent patient reassessment is necessary. If a blind insertion airway device does not successfully secure the airway, the Paramedic must move on to other options. Bag-Valve Mask and Automatic Transport Ventilator Figure 23-31 LMA placement. Face-Mask Ventilation If the Paramedic has attempted to intubate and to place a blind insertion airway device without success, he is faced with a “can’t intubate” situation and his options are lim- ited. Two alternatives remain, either manual ventilation or a surgical airway. If it is possible to face-mask venti- late the patient, then no further interventions are needed (Figure 23-33). Constant vigilance and frequent patient reassessment is the key to good, high-quality non-intubated face-mask ventilation and airway management. An oropharyngeal or nasopharyngeal airway should be inserted in these patients. It is possible that a patient who cannot be intubated can also not be ventilated (a “can’t intubate, can’t ventilate” situ- ation). Trauma, facial hair, burns, or anatomic distortion may lead to this condition. If this is the case, the patient must be Figure 23-32 Combitube placement. prepared for a surgical airway. Intubating Airway Management 447 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. fi ngers to palpate—but not occlude—the patient’s carotid pulses and stabilize the trachea. Once the landmarks have been identifi ed and stabilized, hold a #20 scalpel low in the right hand at a 90-degree angle to the membrane. Make a stab incision in a horizontal plane through the skin and membrane and hold the scalpel in place. The left hand can now release the trachea, grasp the tracheal hook, and place the hook into the incision. Gently pull against the cricoid ring toward the patient’s feet to again stabilize the trachea. Once the cricoid ring is stabilized by the tracheal hook, remove the scalpel. Now, using the right hand, pick up the tracheostomy tube or endotracheal tube and place it into the trachea through the incision. If you are using an endotracheal tube, take care not to insert the tube too far Figure 23-33 Face-mask ventilation using an into the trachea. A mainstem bronchus can easily be intu- automatic transport ventilator. bated with this procedure due to the relatively long length of the endotracheal tube. It is important to note that the patient will bleed dur- Surgical Airway ing this procedure; it is to be expected. Even if the patient is bleeding heavily, the Paramedic’s fi rst priority must be to In the patient that can neither be intubated nor ventilated, secure the airway. Once a tube is safely in place, the issues of emergency access of the trachea via a surgical technique is bleeding can be addressed. mandatory. This technique can be life-saving for the patient Endotracheal tube placement should be assessed in the who has an otherwise unmanageable airway. The three most usual manner. The tube should be secured with a strap which common methods of obtaining this type of airway access ties completely around the neck. The endotracheal tube should are the surgical |
cricothyroidotomy, needle cricothyroido- be trimmed to the shortest length possible without damag- tomy, and placement of a percutaneous cricothyrotomy ing the cuff infl ation system. If a C-collar with an opening device. on the anterior surface is available, this should be placed as Surgical Cricothyroidotomy well. However, the Paramedic must be able to constantly reas- sess the neck for signs of air infi ltration (swelling or crepitus) The surgical cricothyroidotomy is a conceptually simple pro- (Skill 23-6). cedure that involves cutting through the cricothyroid mem- For a step-by-step demonstration of Rapid Four-Step brane and placing an endotracheal tube through that hole. In Surgical Cricothyrotomy, please refer to Skill 23-6 on practice, it is a diffi cult procedure in that it is done under page 462. emergency situations and the factors that make intubation and ventilation diffi cult (trauma, anatomical distortion, or anomalies) also make performing a surgical cricothyroido- Needle Cricothyroidotomy tomy diffi cult. Like all airway procedures, it is best practiced The technique of needle cricothyroidotomy is a simple, fast, before it is needed. and effi cient method of turning an “emergency” (no airway or The equipment needs, discussed previously, include a ventilation) into an “urgency” (defi nitive airway still needed scalpel, a tracheal hook, and a 6.0 to 6.5 mm ID endotracheal but patient now oxygenating). The keys to the technique are tube. The patient should be placed in a supine position and, if good landmark identifi cation and care in ventilation to pre- possible, the neck prepped with an iodine-containing solution vent overpressurization. or alcohol. The patient is positioned supine with the neck in a neutral Although there are a number of ways to perform a surgi- position. The non-dominant hand is used to stabilize the larynx cal cricothyroidotomy, the rapid four-step cricothyroidotomy while the dominant hand locates the cricothyroid membrane. If method71 is simple, relatively safe for the Paramedic, and an a safety catheter is being used, it is inserted through the crico- easy-to-perform procedure. The four steps to this procedure thyroid membrane directed toward the feet in the same manner include identifi cation, incision, traction, and intubation. Each as the insertion into a vein (Figure 23-34). of these steps will be reviewed individually. When resistance decreases, the IV is in the trachea and First, stand or kneel to the left of the patient. Using the the catheter should be advanced to the hub while the needle is left hand, palpate the cricothyroid membrane with the index slowly withdrawn. Once the IV catheter has been advanced to fi nger. If diffi culty is experienced in locating the cricothy- the hub, the safety mechanism on the IV is activated. If a non- roid membrane, begin palpating at the sternal notch and safety IV catheter is used, the device is attached to a 5 to 10 cc move toward the head until the uppermost tracheal ring is syringe. The syringe is aspirated during insertion, which is felt. This is the cricoid cartilage. Use the thumb and middle also toward the feet. When air returns, the whole device is 448 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. with a removable trochar, insertion of a small device with subsequent dilators, or a Seldinger (over the wire) technique. The fi rst class of devices (Figure 23-36) uses a relatively large catheter to puncture the cricothyroid membrane. Once in the trachea, the needle is removed and the catheter advanced Branches of Thyroid cricothyroid cartilage to its maximum depth. It is secured in place and attached to artery a BVM with a built-in 15 mm adapter. These devices have a minimum of parts and are easy to use. The second class of devices (Figure 23-37) is placed through the use of a smaller needle for puncture. Once a small needle is introduced into the airway, serial dilation or placement of a through-the-needle larger catheter allows the size of the original catheter to be increased. Once the largest device is in place, the trochar is removed and the device is secured. There is an adapter on the largest cannula that allows Cricoid a BVM or ventilator to be attached. These devices are also cartilage Vocal void Laryngeal ventricle Figure 23-34 Needle insertion for needle cricothyroidotomy. advanced 5 mm and then the needle is carefully withdrawn while the catheter is advanced to the hub. The catheter is stabilized in place while the high-pressure oxygen source and fl ow control device are attached (they attach with a standard threaded adapter). Although the cath- eter should be secured with tape, it should also be stabilized by hand throughout the entire management so that high pres- sures and movement do not dislodge the catheter. The gas fl ow through a 21 gauge catheter with a 50 PSI source is 1,600 mL/ sec.72 Therefore, ventilation time is 0.5 to 1 second with 3 to 5 seconds (an inspiration to expiration ratio of 1 to 3) between each ventilation to allow adequate expiration. One variant of the needle cricothyroidotomy is the use of an Arrow Rapid Infusion Catheter (RIC) set (Figure 23-35) to increase the size of the catheter. Once a 21 or 16 gauge cath- Figure 23-35 Rapid Infusion Catheter (RIC) set. eter is in place, a small wire is inserted through that catheter (Courtesy of Telefl ex Medical/Arrow International) until the distal end of the wire is in the trachea. The origi- nal IV catheter is removed, a small nick is made in the skin, and the RIC catheter and dilator are threaded over the wire and inserted through the skin to the hub. The dilator and the wire are then removed and the larger RIC catheter remains in place. Percutaneous Devices There are a number of manufacturers of percutaneous airway management kits. As each manufacturer’s device and inser- tion technique is different and new kits are being introduced, it is not practical to examine each specifi c device. Instead, it is important to recognize that there are three general techniques and most devices use a variant of one of these techniques. The three techniques are direct insertion of a larger device Figure 23-36 Needle and trochar-type device. Intubating Airway Management 449 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Post-Intubation Care Once a patient has been intubated, the tube placement con- fi rmed, and the tube secured, there are some procedures that may need to be performed to maximize the patient’s respiratory care. Although ongoing ventilation is the most obvious of these pro- cedures, other care should also be considered. Other procedures include placement of a nasogastric or orogastric tube and tra- cheobronchial suctioning. Post-Intubation Ventilation It is important for the Paramedic to recognize that the major goal of emergency airway management is to oxygenate the patient. Therefore, proper post-intubation ventilation is criti- Figure 23-37 Percutaneous cricothyroidotomy cal to minimize hypoxia. using dilators. Most providers will use the bag-valve-mask device as their standard “ventilator.” Although adequate ventilation can be obtained with the BVM, the fi ner details of its use are not intuitive. The volume of an adult-sized BVM device will range based on the manufacturer but will usually be between 1,500 and 2,000 mL. For an intubated patient, ventilation volumes of 7 cc/kg ideal body weight (3 to 3.5 cc/lb ideal body weight) are usually adequate. At a ventilatory rate of 12 breaths per minute, a 70 kg adult will have a minute ventilation of approximately 6 liters. This is adequate for most patients; those with asthma or other pulmonary disease, however, may require minute ventila- tions of up to 20 LPM. Therefore, ventilation must be adjusted to suit the patient’s clinical condition. Unfortunately, it may be diffi cult to adequately gauge minute ventilation when using a BVM as it is diffi cult to determine exactly what volume is being delivered. Furthermore, using a BVM requires a provider to squeeze the bag, thereby tying up someone who could be Figure 23-38 Percutaneous cricothyroidotomy providing other care. using Seldinger technique. Many services, particularly those performing critical care transports, have begun to use more and more sophisticated ventilators to provide ventilation to intubated patients. These easy to use but tend to have more parts than direct insertion devices may range from selecting preset volume/rate combi- devices. nations to being able to independently control volume, rate, The third class of devices (Figure 23-38) uses a Seldinger, and end-expiratory pressures to being able to select between or over the wire, method of placing a tracheostomy-like tube. pressure control modes, volume control modes, and support A small catheter is used to cannulate the airway and a wire is modes. The most basic parameters to be set are the rate and placed through that catheter. The original catheter is removed volume (or peak pressure); these two parameters establish the and progressively larger catheters are placed until a fi nal, minute ventilation. By being able to set the minute ventila- large tube is placed. The wire is then removed and the device tion, the patient will receive consistent ventilation without secured. Although these devices allow for the placement of factors such as human fatigue playing a role. a large fi nal airway, they have many parts and require some Every manufacturer has special features and charac- degree of dexterity to use. Therefore, their application in the teristics of its ventilators. Therefore, it is important that all prehospital environment is somewhat limited. Paramedics familiarize themselves with the ventilator that Regardless of the percutaneous technique used, there they will be using. The manufacturer should be able to provide are some important rules. Landmark recognition is a critical training and reference materials for the use of its equipment component of correct performance of this skill. Furthermore, and special features of that particular type of ventilation. bleeding is expected. As with other techniques, the Paramedic There are a number of advantages and disadvantages must fi rst secure the airway and then focus on bleeding con- to automatic transport ventilators. Most importantly, they trol. Finally, all of these techniques should be practiced regu- provide consistent and predictable ventilation. They also larly as they require some motor skill and familiarity with the free a provider from the task of squeezing a BVM device. equipment. They are lightweight, relatively inexpensive, and most are 450 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. oxygen powered. Many have high-pressure alarms and other alerts that notify the Paramedic of changes in the airway or of the patient’s condition. Disadvantages include an inabil- ity to detect sudden changes in compliance (e.g., displaced tube, pneumothorax), the start-up costs of the devices, the need to have disposable ventilator circuits available, and the dependence on an oxygen source to provide ventilation. Nonetheless, many agencies fi nd the overall convenience and utility of ventilators offset their disadvantages. Orogastric and Nasogastric Tube Placement All patients who receive positive pressure ventilation before intubation have some degree of gastric infl ation. In adults, this gastric distention increases the risk for vomiting and aspira- Figure 23-39 Nasogastric tube. tion and, to some degree, compromises respiratory mechanics. In the pediatric patient, the same concerns for vomiting and aspiration exist. However, the ventilatory compromise that should be marked or otherwise noted |
as this is the proper occurs with gastric infl ation can make ventilation completely depth of insertion for the tube. ineffective. Therefore, the placement of an orogastric tube, a The tip of the tube is then lubricated and inserted into the single-lumen tube passed through the mouth into the stomach nare parallel to the fl oor of the nose. A common mistake is to to evacuate air from the stomach, in all patients who have angle the tube superiorly during insertion. This tendency can received non-intubated bag-valve-mask ventilation should be be eliminated by putting the index fi nger of the non-dominant considered mandatory. In addition, conscious patients with hand on the tip of the nose and lifting up to pull the nostrils bowel obstruction or toxic ingestions may benefi t from the upward. The tube is then advanced until it strikes the pos- placement of a nasogastric tube, a single-lumen tube passed terior nasopharynx. Gentle pressure and rotation will make through the nose into the stomach to evacuate air from the it turn downward. It should be advanced to the previously stomach. noted insertion depth. Although the patient may gag with cor- There are contraindications to the placement of gastric rect placement, coughing or loss of the ability to speak sug- tubes. Patients with esophageal obstruction cannot have a gas- gest placement of the gastric tube through the vocal cords. In tric tube placed. In addition, caution must be used in placing that case, the tube should be partially withdrawn. Having the a gastric tube in a patient with a history of esophageal disease patient swallow while the tube is being advanced will increase (varices or caustic ingestion) and, in the case of nasogastric the chances of successful placement. tubes, in patients at risk for basilar skull fractures. Once the tube is at its proper insertion depth, immedi- Gastric tubes are long, thin tubes of various internal diam- ate return of stomach contents indicates a gastric placement. eters designed to be blindly placed into the stomach. The tube Even if nothing returns, 500 cc of air should be injected into is sized based on its purpose (decompression of the stomach the tube while the Paramedic auscultates over the epigastrium. or evacuation of contents), the size of the patient, and if naso- Loud sounds confi rm proper tube placement. The tube is then gastric (smaller tube) or orogastric (larger tube) placement is secured to the nose and face with tape and the stomach either planned. A gastric tube, a catheter tip syringe, and some form suctioned or allowed to equilibrate with the outside pressure of lubricant (Figure 23-39) are needed to place the tube. (Skill 23-7). Placement of a nasogastric tube is typically done in an awake patient who will not tolerate an orogastric tube. The For a step-by-step demonstration of Nasogastric patient and equipment must be prepared. Unless contraindi- Tube Placement, please refer to Skill 23-7 on cated, use of a nasal decongestant (e.g., Afrin®) and a topi- page 463. cal anesthetic (e.g., viscous lidocaine or lidocaine jelly) to Orogastric tube placement is generally performed in the premedicate the patient is advised. The patient should be unresponsive, apneic patient after intubation. The patient will examined for nasal pathology (e.g., tumors, trauma, and sep- typically be supine. The tube is measured from the point tal deviation) which would preclude use of the nostril. The just below the tip of the xyphoid to the angle of the jaw and patient should then sit in a neutral position. then to the lips. The patient is prepared by performing a jaw If possible, prewarming the gastric tube will make it pass lift. The gastric tube, already lubricated, is inserted into the more easily. The tube must be measured for size. For a naso- mouth and advanced until it strikes the posterior orophar- gastric tube, the tip of the tube is placed just inferior to the ynx. Gentle manipulation should cause it to turn inferiorly. xyphoid. The tube is then measured to the ear and bent anteri- It is advanced to its proper depth and position is confi rmed orly where it is measured to the tip of the nose. This distance in the same way as for the nasogastric tube. Generally the Intubating Airway Management 451 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. until resistance is met. The catheter is then withdrawn with a total time of no more than 15 seconds. The patient is then oxygenated and ventilated before another suction attempt is made (Skill 23-8). For a step-by-step demonstration of Tracheobronchial Suctioning, please refer to Skill 23-8 on page 465. Special Circumstances Although the Advanced Airway Management Algorithm will provide guidance for most airway management issues, there are a few circumstances that are not easy to predict and do not fall into a single category of action. It is therefore important Figure 23-40 Flexible French suction catheters. for the Paramedic to be well versed in the management of special circumstances. These circumstances include patients with stomas, trauma patients, and pediatric patients. gastric tube is secured separately from the endotracheal tube Stoma Management to prevent a mishap with one from affecting the other. Patients may have stomas for any number of reasons. For Gastric tubes are not without their complications. the Paramedic, it is important to recognize whether the Complications associated with both oral and nasal placement patient only has a tracheostomy (where the airway is oth- include supragastric placement, curling in the oropharynx, erwise intact) or if the patient has had a laryngectomy as endotracheal placement, and tube obstruction. Endotracheal well (where the trachea is rerouted to the skin and there is placement can even occur in the patient who is already endo- no connection between the upper airway and the trachea). tracheally intubated, particularly if a smaller diameter gastric Patients with complete laryngectomies are completely tube is used. For nasogastric (NG) placement, nasal trauma dependent on the patency of their tracheostomy to venti- can lead to extensive bleeding. The patient with an orogastric late. Patients may also have a well-healed stoma or may (OG) tube is at risk of biting the OG tube if some type of bite still have a tracheostomy tube in place. If there is a tube block protection is not used. Excessive force during place- in place, it is at risk for occlusion and displacement with ment can cause airway injury, laryngeal injury, and esopha- subsequent obstruction. geal injury. Tracheostomy tubes and stomas may become occluded with mucus or other substances. Often, simple suction Tracheobronchial Suctioning maneuvers are suffi cient to clear these orifi ces. Suctioning Many patients who require intubation have some degree of lung is performed by preoxygenating the patient and injecting pathology. This can range from aspiration to thick mucus plug- 2 to 3 cc of normal saline into the stoma. The patient exhales ging to blood. Once a patient has been intubated, the Paramedic and a soft-tip catheter is inserted until resistance is met. The has access to the trachea and bronchial tree for suctioning in site is then gently suctioned. If there is an inner cannula to the a way that is not possible without intubation. Therefore, the tracheostomy tube, it can be removed and either replaced or technique of deep tracheal or tracheobronchial suctioning, cleaned and returned. direct suctioning of the secretions in the bronchial tree, is an Over time, a stoma may undergo stenosis or narrowing. important skill to master. This can be a life-threatening condition if stoma stenosis pre- Soft, long, and thin suction catheters (Figure 23-40) are vents ventilation and the patient can acutely decompensate. used for tracheobronchial suctioning. These catheters can The patient should have an endotracheal tube placed through either be single-use catheters or can be designed as a pre- the stoma immediately to relieve the obstruction. assembled component of a ventilator circuit. This second Tube replacement is accomplished through the use of a type of catheter offers the advantage of not requiring that the tracheostomy tube or an endotracheal tube. In addition, criti- v entilator be unhooked from the endotracheal tube before cally ill patients with stomas who need to be ventilated should suctioning. These devices do, however, add more dead air have a tube placed to facilitate ventilation. The tracheostomy space to the ventilator circuit. tube or cuffed endotracheal tube is lubricated. It is advanced The patient should be prepared for deep tracheal suction- through the stoma until the cuff is in approximately 2 cm. ing with aggressive preoxygenation. If the patient has copi- The cuff is then infl ated, the position confi rmed, and the tube ous or thick secretions, a 3 to 5 cc saline fl ush down the endo- secured to the neck. Care must be taken to avoid excessive tracheal tube followed by two to three quick ventilations may movement of the tube as there is only a small amount of the help. The catheter should be advanced carefully and inserted tube in the airway. 452 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. The Trauma Patient The Pediatric Patient Airway management of the trauma patient is not fundamen- Pediatric patients present the Paramedic with a special set of tally different from airway management of any patient. There issues and problems. Although the fundamental equipment are some important considerations, however. These include and techniques are the same, the anatomic and physiologic concerns about airway injuries, cervical spine movement, the differences discussed in Chapter 20 result in differences in need for early interventions for respiratory compromise from the airway management of these patients. As was discussed in chest wall or pulmonary injuries, and consideration for the Chapter 22, good face-mask ventilatory skills are mandatory early and aggressive use of sedation and paralysis. for pediatric airway management. Any patient experiencing a traumatic injury is at risk for trauma to the airway itself. When assessing a trauma patient, the Paramedic must quickly evaluate the impact of all injuries Best Practice on the airway and how they will affect his decisions and tech- Traditionally, it has been accepted that prehospital intubation niques. Burns tend to produce early and signifi cant airway of pediatric patients is good care. Studies have demonstrated damage requiring rapid intubation. Laryngeal trauma can dis- that Paramedics can perform pediatric endotracheal intuba- tort anatomy, obstruct the airway, and produce copious airway tion74 although usually with higher complication rates and bleeding. Tracheal transection makes successful orotracheal lower success rates than for adults.75–77 Most of these stud- intubation unlikely. An open tracheal transection, however, ies have been retrospective in nature and therefore are some- invites intubation through the wound. When managing a trau- what limited by study design and data collection. The only matized airway, suction and good tube placement confi rma- major prospective trial on prehospital pediatric endotracheal tion skills are critical. intubation demonstrated a trend toward worse outcomes with All trauma patients with an altered level of conscious- intubation.78 ness or an appropriate mechanism must be considered to have Although no single trial should completely change prac- a cervical spine injury. Therefore, all of these intubations tice, the fi ndings of this study should cause all Paramedics must be performed with the patient’s head in a neutral posi- and medical directors to give strong consideration to review- tion. One provider should be assigned the task of maintaining ing system pediatric intubation success rates and outcomes. C-spine immobilization and the C-collar should be opened At present, there is no recommendation for or against pedi- anteriorly to facilitate jaw movement. Always remember that atric |
intubation. What is clear, however, is that excellent apnea in an otherwise apparently uninjured patient may rep- non-intubated face-mask ventilation skills are important in resent a spinal cord transection. the management of critically ill children. Trauma to the chest can cause considerable injury. Two important injury processes—fl ail chest and tension The Advanced Airway pneumothorax—will have an impact on airway and ventila- Management Algorithm tion management. In fl ail chest, two or more fractures of two or more consecutive ribs disrupt the stability to the rib cage, There are signifi cant anatomical and physiological differences resulting in paradoxical collapse inward of that section of between adult and pediatric patients. Earlier in this chapter, the chest wall during inspiration. This results in underinfl a- differences in the size of equipment were noted, although the tion of the affected lung. In addition, the trauma necessary to equipment itself is fundamentally the same. In addition, the produce a fl ail segment will also usually injure the underly- Advanced Airway Management Algorithm can be applied to ing lung. Therefore, early stabilization of the fl ail segment is adults and pediatric patients. There are some important dif- important to maximize the patient’s ventilatory function. ferences, however, in the techniques that should be applied. A pneumothorax may also cause signifi cant respiratory compromise. Although there is emerging evidence that pre- Patient Preparation hospital needle decompression does not have a signifi cant The anatomic differences of the pediatric head make posi- impact on patient outcome,73 few would argue that a patient tioning much more important. Laying a child supine without with respiratory compromise, unilateral diminished or absent padding will result in neck fl exion with “crimping off ” of the lung sounds, and shock should not receive the benefi t of a airway (Figure 23-41). However, excessive head extension needle decompression. Early recognition and rapid diagnosis can also “crimp off ” the airway. Therefore, neutral position- of the injury is absolutely necessary. ing is much more ideal. Trauma patients, particularly multi-trauma patients, Airway manipulation of children under age 8 increases often are suffi ciently ill to have lost their airway refl exes and vagal tone and may become a major concern during airway to be combative, but not to be obtunded. This is particularly management. These children can rapidly become brady- true if the patient has a head injury. Early and aggressive cardic and asystolic. Therefore, premedication with atropine use of medication-facilitated and rapid sequence intubation (0.02 mg/kg, minimum 0.1 mg, maximum 0.5 mg) is manda- techniques to secure these patient’s airway is warranted. The tory in all of these children. Use of atropine or glycopyrrolate issue will be discussed in greater detail in Chapter 24. will also help to minimize secretions. Intubating Airway Management 453 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. markers and should be positioned on either side of the vocal cords. Although ultimately the tube may need to be moved due to fi ndings on patient examination, these markers gener- ally do an excellent job of placing the tip of the endotracheal tube at about the middle of the trachea. Tube Placement Confi rmation Confi rming the endotracheal tube placement in pediatric patients can be challenging. Due to the smaller body size, lung sounds and epigastric sounds may be hard to distin- guish. The esophageal intubation detector device may report an esophageal intubation despite placement in the trachea due to low lung volumes. However, in a patient with a pulse, an appropriately sized colorimetric end-tidal carbon dioxide detector or capnography device will work. Therefore, con- Figure 23-41 Overextension can cause stant reassessment of the end-tidal carbon dioxide and vigi- obstruction in a pediatric airway. lant monitoring of the patient’s status is critical. Once the tube position is confi rmed, continuous moni- Pediatric Intubation toring for a displaced endotracheal tube is also critical. The Techniques for selecting the proper-sized blade and endotra- smaller size of pediatric patients puts them at high risk for cheal tube were discussed previously. In most children under tube dislodgment. Any changes in the patient status should 4 to 5 years of age, a straight blade is the most appropriate make one consider the “DOPE” mnemonic: displaced endo- blade to use. For older children, the Paramedic should use the tracheal tube, obstructed tube, pneumothorax, or equipment blade type with which she is most comfortable. failure. Immobilization of the patient is an important preven- When intubating, the redundant and loose oral mucosa tative measure against tube dislodgement. has the potential to compromise visualization of the vocal cords. Therefore, purposeful precise movement to control Airway Rescue Devices as much tissue as is possible is mandatory. In addition, care The major difference between adult and pediatric patients must be taken to minimize bleeding from these very friable regarding rescue devices is that the King airway and the tissues. Suction, if used, should be applied judiciously and Combitube are not sized for pediatric patients. However, there never directly to the tissue. is evidence that the laryngeal mask airway (LMA) is an excel- The pediatric patient has minimal respiratory reserve. lent rescue device for children.79, 80 The LMA is sized for infants Therefore, hypoxia occurs early and prolonged intubation and children and is easily placed. Therefore, the LMA should attempts put the patient at risk for rapid desaturation. Failed be the rescue airway of choice for pediatric patients in whom intubation attempts should be abandoned early in favor of orotracheal intubation cannot be performed. face-mask ventilation. In addition, as face-mask ventilation may result in better outcomes than intubation anyway, a sin- Surgical Airway Options gle failed intubation attempt should cause the Paramedic to The small size of the pediatric airway and the signifi cant risk consider whether further attempts are warranted or if face- of airway scarring contraindicates all surgical airway manage- mask ventilation is the better choice. ment techniques with the exception of the needle cricothyroido- When passing the endotracheal tube, the smallest diam- tomy. This technique can be performed on children of all ages. eter of the pediatric airway is at the cricoid ring. Therefore, if Catheter placement should be performed in the same manner the tube passes through the vocal cords but does not advance as the placement of an IV in a vein. Although the ideal location any further, a smaller tube may be needed. A small air leak is through the cricothyroid membrane, it is often impossible around the tube is acceptable and, if airway pressure manom- to locate this structure in very small infants. Therefore, a gen- etry is being performed, the leak should occur at around eral location of the thyroid cartilage should be determined 10 cm H O. This leak acts as a “safety valve” for preventing 2 and the catheter placed in the midline just inferior to the thy- acute barotrauma. roid cartilage. Short inhalation times and a smaller catheter The pediatric endotracheal tube has a pair of black lines at should also be used to minimize peak pressures, to deliver appro- the distal end of the endotracheal tube. These lines are depth priate volumes, and to minimize the risk of acute barotrauma. 454 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Skill 23-1 Orotracheal Intubation 1 Prepare equipment. 2 Position patient. 3 Holding laryngoscope in the left hand, place it in the right 4 Pass endotracheal tube. side of the mouth and sweep to the left. 5 Confi rm placement. 6 Secure the endotracheal tube. Intubating Airway Management 455 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Skill 23-2 Nasotracheal Intubation 1 Prepare equipment. 2 Position patient. 3 Use afrin and lidocaine jelly to prepare nostril. 4 Insert right nostril. 5 Pass into nasopharynx. 6 Listen for loudest breath sounds. 456 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Skill 23-2 (continued) 7 Advance during inhalation. 8 Confi rm placement. 9 Secure nasotracheal tube. Intubating Airway Management 457 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Skill 23-3 Digital Intubation 1 Prepare equipment and confi rm absence of gag refl ex. 2 Insert hand into mouth and walk fi ngers down tongue. 3 Lift epiglottis with middle fi nger. 4 Guide endotracheal tube into trachea. 5 Confi rm placement. 6 Secure endotracheal tube. 458 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Skill 23-4 Elastic Gum Bougie 1 Perform laryngoscopy in the usual fashion. 2 Place bougie by aiming the tip midline and anterior. Bougie Cartilage rings Vocal cord 3 The bent tip will click as it passes across the cartilage rings 4 Assistant passes endotracheal tube over bougie while and advance until the black band is at the corner of the mouth. keeping the tissues out of the way with the laryngoscope. Intubating Airway Management 459 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Skill 23-4 (continued) 5 Insert endotracheal tube. 6 Remove bougie. 7 Confi rm placement and secure endotracheal tube. 460 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Skill 23-5 King Airway Placement 1 Grasp tongue and jaw, lifting toward ceiling. Place tip of tube 2 Rotate the airway counterclockwise as it is advanced. toward oropharynx, approaching from the patient’s right. 3 Advance until the orogastric port is at the level of the teeth. 4 Infl ate balloon, bag-ventilate the patient, and auscultate breath |
sounds. 5 Slowly withdraw while listening until breath sounds are the 6 Confi rm placement and secure airway. loudest. Intubating Airway Management 461 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Skill 23-6 Rapid Four-Step Surgical Cricothyrotomy 1 Position to the patient’s left side. 2 Palpate landmarks and stabilize cricoid ring with left hand. 3 Make stab incision with scalpel over the cricothyroid 4 With the left hand, place tracheal hook around the cricoid membrane. In obese patients, make a vertical incision and use cartilage and gently pull toward the patient’s feet. the handle to bluntly dissect the tissue until you visualize the cricothyroid membrane. Hold scalpel in space. 5 Place endotracheal or tracheostomy tube. 6 Confi rm placement, control bleeding, and secure tube. 462 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Skill 23-7 Nasogastric Tube Placement 2 Position and premedicate if possible. 1 Prepare equipment. 3 Measure for length. 4 Insert lubricated tube in nostril. Intubating Airway Management 463 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Skill 23-7 (continued) 5 Ask patient to swallow as tube is advanced. 6 When tube is at length, confi rm placement by instilling 60 cc of air with a Toomey syringe while auscultating the epigastrium. 7 Secure the tube with tape. 464 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Skill 23-8 Tracheobronchial Suctioning 1 Prepare equipment and don sterile gloves. 2 Place 3 to 5 cc of saline down endotracheal tube as a fl ush. 3 Advance suction catheter until resistance is met. 4 Apply suction. 5 Twist the catheter while withdrawing with suction on. 6 Suction sterile saline to clear suction catheter. Intubating Airway Management 465 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. It is critically important that the Paramedic master basic, non-intubating airway management. However, the defi nitive management of the airway involves endotracheal intubation. Even under the best of circumstances, however, there are times when the Paramedic cannot intubate a patient. Therefore, it is important for the Paramedic to have a plan and alternatives. The Advanced Airway Management Algorithm, used along with the Paramedic’s skills, should provide the Paramedic with the tools necessary to perform defi nitive advanced airway management. Key Points: • An endotracheal tube (ET tube) offers direct • ET tubes are sized based on their internal diameter access to a patient’s airway. Even though it does and range from 2.5 to 10.0 mm. Selection of size not absolutely prevent aspiration, it signifi cantly for pediatric patients can be done based on age, decreases the rates of aspiration. estimating the diameter of the patient’s small fi nger or nare or using length-based tapes. • The endotracheal tube also allows the Paramedic to perform intermittent positive pressure ventilation, • Nasotracheal intubation is the placement of an tracheobronchial suctioning, and medication endotracheal tube through the patient’s nostril and delivery. Perhaps the greatest advantage over into the trachea. Blind nasotracheal intubation can non-intubated ventilation is that it does not cause only be performed on a breathing patient. Nasal tubes gastric insuffl ation. are softer and more pliable than standard tubes to allow them to curve more easily along the posterior • Disadvantages of endotracheal intubation include oropharynx. They may have a small ring or “trigger” the fact that air is no longer fi ltered, warmed, or that is used to curve the tip of the tube anteriorly. humidifi ed by the upper airway. Complications • Although not a “sterile” technique, airway of intubation include bleeding, laryngospasm, management should at least be a “clean” laryngeal swelling, mucosal necrosis and erosion, technique and efforts should be made to minimize and vocal cord damage. Patients are also at risk for contamination of the endotracheal tube. barotrauma and infections related to ventilation devices. Overventilation of the lungs can increase • Preparation of the endotracheal tube includes intrathoracic pressures, causing a decrease in applying lubricant, checking the cuff for leaks, and systemic blood pressures. placing a stylet. Several other sizes of ET tubes should also be available. • The endotracheal tube provides a conduit for • The laryngoscope is the primary device used to oxygenation and ventilation between the patient’s visualize the larynx. The handle serves as a power lungs and the ventilator (person or machine). source and grip point for the Paramedic and the • blades are designed to provide a view of laryngeal The primary components of an endotracheal tube opening through control of the tongue and the are the tube, the cuff that infl ates to secure and epiglottis. The two most commonly used styles of seal the tube below the level of the cords, and the blades are the Macintosh and Miller blades. 15 mm adapter that can be connected to a BVM or ventilator. Pediatric tubes are often uncuffed. • The Macintosh blade is a curved blade with a large fl ange and fl at surfaces. Common sizes range from • Common features of the endotracheal tube include 1 to 4. The tip of the blade is intended to fi t into length markings in centimeters and a beveled distal the vallecula and elevate the epiglottis via the end with a “Murphy eye.” hyoepiglottic ligament. 466 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. • The Miller blade is a straight blade with common intubation. Conversely, an esophageal intubation sizes from 00 to 4. The straight blade is designed to may be mistaken for an endotracheal intubation open a conduit to the larynx on the right side of the with gastric insuffl ation, leading to ingestion of mouth and hold the tongue in the midline to the left carbonated beverages and antacids. side of the mouth. The tip of the blade is designed to capture and lift the epiglottis. • The least expensive, and probably most commonly used, device for measuring end-tidal carbon dioxide • Selecting the appropriate size and type blade is the colorimetric device. These devices are simply depends on the size of the patient and the clinical encapsulated pieces of litmus paper over which the context. Miller blades are typically used for children exhaled breath fl ows. A color change indicates CO2 under 5 years of age and for trauma patients. is being exhaled and the ET tube is properly placed. • The blade is attached to the crossbar of the handle • Capnometry devices give a single, numeric peak until it clicks into place. Once the blade is rotated reading of the exhaled CO2. End-tidal capnography in place, the light should activate. The Paramedic provides the Paramedic with the numeric values for should make sure the light is white in color, the both the peak and trough ETCO2 levels and displays bulb is tightly screwed into the blade, and the light a graph of the exhalation curve. is steady and bright in intensity. • Supraglottic airway devices or blind insertion airway • The stylet is placed inside an endotracheal tube devices (BIADs) include the King LTS-D airway, the to provide rigidity and can be shaped to maximize esophageal-tracheal Combitube (ETC or Combitube), control of its distal tip and improve the chances of and the laryngeal mask airway (LMA). The laryngeal successful placement. It is important that the distal mask airway, in essence, moves the mask of face- end of the stylet not extend beyond the Murphy’s mask ventilation from the face to the opening of the eye on the endotracheal tube. A stylet is generally larynx. The mask should be infl ated to assure that not used for nasotracheal intubations. it holds air and the distal tips of the mask should be • lubricated to improve ease of placement. There are numerous devices for securing the endotracheal tube. Regardless of the device, it • The esophageal-tracheal Combitube (ETC) is a is important that the endotracheal tube not be double-lumen device with two separate and distinct able to move. Because the risks of accidental tube lumens that are placed in the esophagus (90% to 99% dislodgment during patient movement are high, of the time). However, tracheal placement of the a cervical collar can be applied to the patient to ETC is possible. Each has two cuffs: a large proximal minimize neck extension and fl exion. cuff designed to seal the hypopharyngeal portion • of the airway and a smaller distal cuff designed to To confi rm the proper placement of an ET tube, the seal the esophagus or trachea, depending on the Paramedic should have a stethoscope immediately placement. available for the auscultation of lung sounds. An esophageal detection device should also be • No special equipment is needed for supraglottic available to use to confi rm endotracheal tube airway devices. It has been demonstrated to placement. cause less C-spine movement than conventional • endotracheal intubation. The devices are easy to End-tidal carbon dioxide (ETCO2) measurement place and may be a useful alternative when patients and monitoring has become the gold standard for are in unusual positions. Disadvantages include the both confi rming endotracheal tube placement inability of medication administration and deep and monitoring patient status, ventilation, and suctioning of the lungs. An elastic gum bougie is a continuing tube placement. A limit to ETCO2 is small diameter, semi-rigid device that is directed that, in patients in cardiac arrest, the lack of through the vocal cords and into the trachea to carbon dioxide may be mistaken for an esophageal serve as a guide for an endotracheal tube. The Intubating Airway Management 467 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. endotracheal tube is then threaded over the Paramedic can utilize the modifi ed jaw-thrust proximal end and advanced into the trachea. maneuver or BURP technique to create ideal • positioning. Lighted stylettes are |
essentially malleable stylettes with a bright light source. When placed in the • The fi nal step in patient preparation is the trachea, provide a bright, well-circumscribed light appropriate use of sedatives and paralytic agents. that can be seen in the midline of the trachea. • The process for intubation can be broken down into • One of the other advantages, besides illumination, four steps: of the close proximity of the trachea to the anterior 1. Visualizing the vocal cords neck is that surgical airway management can be 2. Passing the endotracheal tube achieved rapidly and effectively. A true or classical 3. Confi rming endotracheal tube placement surgical airway is a relatively simple process that 4. Securing the endotracheal tube involves the identifi cation of the cricothyroid membrane, cutting a hole through the cricothyroid • Endotracheal intubation is a team activity, and the membrane, and placing an endotracheal tube or Paramedic may ask other EMS personnel to provide cuffed tracheostomy through that hole. cricoid pressure, BURP technique, or external laryngeal manipulation. • It is important to note that a surgical airway should be performed only if that patient cannot • The tip of the MacIntosh blade is designed to fi t into be intubated, a rescue device cannot be placed, the vallecula. When lifted anteriorly and inferiorly, and the patient cannot be ventilated with standard the blade lifts the hyoepiglottic ligament, which face-mask techniques. pulls the epiglottis anteriorly and reveals the vocal cords. • Needle cricothyrotomy ventilates the lungs using special high-pressure devices after a needle • The Miller blade is designed to pin the epiglottis device is used to introduce a catheter or against the base of the tongue anteriorly and tracheostomy tube. provide a straight-on view of the vocal cords. The tip of the blade lifts up the epiglottis to reveal the • To prepare the patient for intubation, the vocal cords. Paramedic should fi rst assess the level of diffi culty before attempting airway management. The • The Cormack-Lehane grading system grades the 3-3-2 rule and the “LEMON” law are two methods view of the glottic opening by how much is occluded for assessing a patient’s airway along with the by the tongue. Grade I is a clear view of the entire Paramedic assigning a Mallampati score. glottic opening while IV is visualization of the tongue or soft palate only. • When positioning the patient for endotracheal intubation, the sniffi ng position is considered to be • To assist the Paramedic in visualizing the cords, an the intubation position of choice. Both the sniffi ng assistant can use a fi nger or rigid suction catheter to position and head-tilt, chin-lift maneuvers help hook and retract the corner of the patient’s mouth. to align the oral, pharyngeal, and laryngeal axes, • Suctioning itself may be used to improve allowing for the best view during intubation. visualization and minimize airway and soft tissue • For patients who are unable to lie fl at, the Head trauma. Elevated Laryngoscopic Position (HELP) may • Magill forceps are used to remove large foreign be used. bodies occluding the airway. If the foreign body is • Neck fl exion and head extension are contraindicated subglottic and cannot be grasped with the Magill in trauma patients. While providing in-line forceps, it should be pushed into a mainstem stabilization from the inferior direction, the bronchus with an endotracheal tube. The tube is 468 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. then withdrawn to above the carina to allow at • The endotracheal tube placement is confi rmed in least one lung to be ventilated. the same manner as in an orotracheal intubation. • If the cords are closed due to laryngospasm or only • If the intubation fails, the Paramedic should assess partially open, the Paramedic should apply gentle reasons why it failed and make attempts to correct pressure to the lip of the tube bevel between the it before attempting intubation a second time. cords, which may cause them to relax suffi ciently to pass the tube. The tube or the stylet should not be • A digital intubation is a blind technique that is “forced” between the cords. useful not only for supine patients, but patients who • are in a sitting position or for whom access to the When the fi rst breath is delivered, the epigastrium head is limited. should be auscultated. Loud noises over the epigastrium with abdominal distention and no chest • The elastic gum bougie is placed under direct movement strongly suggest esophageal placement. visualization with a laryngoscope. The tip of • the bougie is advanced anterior to the posterior Diminished or absent lung sounds on the left are arytenoids until the tip “clicks” along the tracheal often due to the endotracheal tube being placed in rings. An endotracheal tube is threaded over the the right mainstem bronchus. external end of the bougie and advanced into the • Once the tube position is assessed by auscultation, trachea. the Paramedic should assess placement using end- tidal carbon dioxide measurement. The Paramedic • When the Paramedic is performing translaryngeal should look for readings of 30 to 40 with a wave that illumination with a lighted stylet, the stylet is rises and falls appropriately with ventilation and has advanced until a focal, bright midline glow is visible a consistent shape. at the level of the larynx. • For patients without spontaneous circulation, the • Supraglottic airway devices provide a method of at Paramedic should use an esophageal detector device least partially securing the airway in the diffi cult- for confi rmation of endotracheal tube placement. to-intubate patient. The three most commonly used devices, as described earlier, are the • The mnemonic DOPE can help the Paramedic 1. King LTS-D airway remember the causes of problem intubations. 2. The laryngeal mask airway • 3. The esophageal-tracheal Combitube It is important that the tube position be assessed after each move. • When performing a needle cricothyroidotomy, • proper technique requires good landmark Nasal intubation is indicated for patients who are identifi cation and care in ventilation to prevent diffi cult to access or, due to their disease process, overpressurization. are likely to experience rapid decompensation if they lay fl at. • Percutaneous devices include the direct insertion of • a larger device with a removable trochar, insertion Contraindications to nasotracheal intubation include of a small device with subsequent dilators, or use of apnea, evidence of basilar skull fracture, or inability a Seldinger (over the wire) technique. to pass the tube through a nare. • • Post-intubation care involves ventilating, monitoring The tube should be placed in the most patent nare the airway, placing a nasogastric or orogastric tube, with the tip of the tube parallel to the fl oor of the and performing tracheobronchial suctioning. nose. A Beck Airway Airfl ow Monitor (BAAM) should be used to detect breath sounds. The tube is then • Automatic transport ventilators can provide the advanced through the cords during inspiration until Paramedic consistent and predictable ventilation; approximately 2 cm protrude from the nose. control over volume, rate, and expiratory pressures; Intubating Airway Management 469 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. and high-pressure alarms. Disadvantages include • Face-mask ventilation skills are important in the its dependence on an oxygen source to provide management of critically ill children. ventilation. • The Paramedic should note that the pediatric • To reduce the risk of vomiting or aspiration caused patient has minimal respiratory reserve. Prolonged by gastric infl ation, the Paramedic should place an intubation attempts put the patient at risk for rapid orogastric or nasogastric tube. desaturation. • Soft, long, and thin suction catheters are used for • The LMA should be the rescue airway of choice for tracheobronchial suctioning. pediatric patients in whom orotracheal intubation • cannot be performed. Any patient experiencing a traumatic injury is at risk for trauma to the airway itself. • Needle cricothyroidotomy can also be performed on • children of all ages. With the assessment fi ndings of a fl ail chest injury or tension pneumothorax, the conditions should be • To minimize peak pressures, short inhalation times treated during airway and ventilatory management. and a smaller catheter should be used to deliver • appropriate volumes, and to minimize the risk of Early and aggressive use of medication-facilitated acute barotrauma. and rapid sequence intubation techniques to secure these patients’ airways is warranted with trauma patients who have lost their airway refl exes and are combative, but not to be obtunded. Review Questions: 1. Weigh the advantages and disadvantages of 6. What does continuous end-tidal capnography endotracheal intubation. offer the Paramedic? 2. Describe the components of an endotracheal 7. For each of the following blind insertion and nasotracheal tube. airway devices, describe the preparation and 3. Create a chart that compares and contrasts the technique for insertion: King LTS-D airway, Miller blade with the Macintosh blade. the esophageal-tracheal Combitube (ETC or 4. A Paramedic is presented with a patient Combitube), and the laryngeal mask in severe respiratory distress who is airway (LMA). decompensating quickly. How would the 8. How can the use of an elastic gum bougie make Paramedic quickly and effi ciently assess the the fi rst attempt at endotracheal intubation the patient’s airway? best attempt? 5. The Paramedic decides that the patient 9. The process for intubation can be broken down requires endotracheal intubation. While the into four steps. Describe each step. team members are performing bag-valve- 10. Why is it important for the Paramedic to mask ventilations with cricoid pressure, what reassess tube position each time the patient equipment must the Paramedic have prepared, is moved? What are some causes of tube checked, and ready before breaking the displacement, and how would the Paramedic mask seal? know that it is out of place? 470 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. 11. If attempts to intubate and place a BIAD fail, done to remedy this situation and improve the what two alternatives remain for the Paramedic? patient’s oxygenation and ventilation? 12. Describe the technique for landmark 14. Who should receive an orogastric or nasogastric identifi cation for a needle cricothyroidotomy. tube? How is each prepared for placement in 13. After intubation, the Paramedic notices copious the patient? thick secretions, decreased O2 saturation, and 15. What considerations must be made for poor ventilatory compliance. What can be intubating the pediatric patient? Case Study Questions: Please refer to the Case Study at the beginning of the 2. What could they have done to help prevent the chapter and answer the questions below: patient’s vomiting? 1. Why were the emergency medical responders 3. What indications did the Paramedic have to experiencing problems with the patient intubate the patient? vomiting? References: 1. Hazinski MF, eds. PALS Provider Manual. Dallas: AHA; 2001:100. 10. Zaleski L, Abello D, Gold MI. The esophageal detector device: 2. Vilke GM. Estimation of pediatric patient weight by EMT-Ps. does it work? Anesthesiology. 1993;79(2):244–247. J Emerg Med. 2001;21(2):125–128. 11. Tanigawa K, Takeda T, Goto E, Tanaka K. Accuracy and reliability of 3. Hofer CK. How reliable is length-based determination of body the self-infl ating bulb |
review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Medication-Facilitated Intubation 475 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. OVERVIEW Although medication-facilitated and rapid sequence intubation have been relative newcomers to paramedicine, they have become very useful tools in airway management. This chapter outlines the key differences in sedative agents used for intubation and the mechanisms of action for both depolarizing and non-depolarizing neuromuscular blockers. Not all patients should receive paralytic agents. This chapter will examine the issue of whether or not paralytics should be used in the prehospital environment. This review will then be followed by a discussion of the medications used for medication-facilitated and rapid sequence intubation. The “Nine P’s of RSI” will be reviewed, as well as patient assessment and the decision to administer paralytics. Medication-Facilitated Intubation the Paramedic takes a patient with an ability to maintain his airway and ventilate and then eliminates those abilities. Paramedics have always done an excellent job of taking pro- Extraordinary clinical judgment is necessary for anyone in cedures and techniques developed for the in-hospital setting the position to paralyze a patient. Nonetheless, there is clear and adapting them for use in the prehospital environment. evidence that patients who receive paralytics have better out- In addition, many medications have been validated in the comes than those who receive only sedatives.2 When used prehospital setting, sometimes before being validated in properly, sedation and paralysis enable otherwise impossible the hospital environment. It is therefore no surprise that in the intubations and eliminate the need for face-mask ventilation arena of airway management, the techniques of medication- and its associated complications (aspiration, gastric disten- facilitated and rapid sequence intubation have been trialed tion, etc.). Paralytics, therefore, play an important role in and applied in the prehospital setting. As with some other managing patients’ airways. techniques, however, the question of whether Paramedics It is important to recognize that if a Paramedic is going should perform these skills was not nearly as well researched to perform rapid sequence intubation with paralytics, then he as whether EMS providers could perform them. Only recently or she must be properly trained and profi cient in adequate has that question been addressed. alternative airway techniques. Although proper patient selec- Medication-facilitated intubation is not a new tech- tion should minimize the risk of paralyzing a patient who can nique. In fact, it has been used for decades in the operating neither be intubated nor ventilated, the risk exists that this room and emergency department settings. The use of adjunc- situation might occur. If it does, an alternative is mandatory tive medications, like any other adjunct to intubation, has to prevent hypoxic complications. Although the question of been (and should be) seen as one more tool to protect patients whether or not Paramedics should be using paralytics may and improve their quality of care. Broadly speaking, medica- not be clearly answered, the fact remains that many provid- tions for airway management can be divided into those that ers are using paralytics and therefore it is incumbent on the provide sedation and those that cause muscular paralysis. Paramedic to be familiar with this tool. In general, many more intubations are performed with sedatives alone. Many EMS agencies and medical direc- tors are more comfortable with sedative-facilitated intu- Prehospital Provider Use of Paralytics bation than with the use of paralytics. Using a variety of The use of paralytic agents to facilitate intubation is a long- sedative agents, Paramedics are able to make patients more standing source of controversy among Paramedics and medi- comfortable, less anxious, and amnestic to the events of the cal directors. The research for and against the use of paralytics intubation. Some newer agents such as etomidate are able has not clearly demonstrated that paralytics have a defi nitive to provide suffi cient sedation to often eliminate the need role in daily EMS practice. Conversely, there is strong evi- for paralytics.1 Sedative-facilitated intubation is therefore dence that paralytics can be used safely by selected groups of becoming a common approach to intubation of the non- Paramedics providing that they have adequate training, good cardiac arrest patient. medical direction and medication utilization review, and a Paralytic agents can be some of the most dangerous rescue device. medications Paramedics can administer. By providing and One of the largest studies in support of prehospital use performing the emergency care which causes paralysis, of succinylcholine is a 20-year retrospective study by Wayne 476 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. and Friedland.3 Spanning 20 years of practice, this retro- Pharmacological Adjuncts spective review evaluated 1,657 consecutive intubations. for Intubation Overall, a 95.5% successful intubation rate was found. There was a 0.3% unrecognized esophageal intubation rate As was discussed previously, the pharmacological agents that that was almost eliminated with the addition of capnography facilitate intubation can be divided into those that provide and esophageal detector device use. The remaining patients sedation and those that cause paralysis. In addition, adjunc- who could not be intubated were successfully managed with tive medications that are often used in RSI include vagolytics alternative methods. This study provides strong support for (atropine) and lidocaine. It is important to be familiar with the prehospital use of paralytics. Similarly, a retrospective all of these medications as they are used in the setting of study by Hedges et al.4 conducted 10 years before Wayne intubation. and Friedland’s study had suggested a similar effi cacy and Sedatives safety profi le for succinylcholine-assisted intubation. Sev- eral other small studies have also addressed the issue, each Sedative agents are medications that are used to decrease a demonstrating that out-of-hospital providers can success- patient’s level of consciousness, cause muscular relaxation, fully perform rapid sequence intubation.5–7 and cause amnesia to the intubation. There are a number A more recent study by Ochs et al.8 has clarifi ed some of different sedatives with varying hemodynamic effects, questions concerning the utility of paralytic-assisted intuba- respiratory effects, and side effects. It is important that the tions. Their study, which focused on head injured patients P aramedic be an expert on the agents that he or she will use. with otherwise unmanageable airways, demonstrated an 84% It is important to recognize that no one agent is ideal for all successful intubation rate. Of the remaining patients, all but patients. Therefore, familiarity with a number of agents and one were successfully managed with a Combitube. The last their characteristics allows for an educated decision about patient was successfully managed with BVM ventilation. which agent to use. Four of the most commonly used agents Although this study certainly indicates that prehospital use of (and representative of the major classes of prehospital agents) succinylcholine will result in some degree of airway manage- are midazolam (a benzodiazepine), etomidate, ketamine, and ment in the vast majority of patients, the intubation failure fentanyl (a narcotic). Understanding these medications and rate of 16% raises concerns about whether or not fi eld EMS others in their respective classes will allow the Paramedic to providers get enough experience with routine intubations to select the most appropriate medication for a patient. expertly manage every airway with which they are faced. Midazolam Nonetheless, the study population is certainly one in whom airway management has been demonstrated to be critical.9,10 As a class, benzodiazepines are probably the most com- Furthermore, the use of a supraglottic airway device (dis- monly used medications for sedation in the emergency air- cussed in Chapter 23) is a clearly recognized and appropriate way management arena. This use comes from familiarity alternative to airway management in the patient with an oth- and a history of safe and effective utilization. Midazolam erwise unmanageable airway. This study, therefore, provides is chosen as a representative of this class because it is short support for the prehospital use of paralytics for critically ill acting, shares the characteristics of the other benzodiaz- trauma patients. epines, and has been studied in the prehospital environment Consistently, the most important factors in the success of as a sole agent to facilitate intubation.2,11 Other benzodiaz- RSI programs have been the involvement of an active medi- epines that are used for intubation include diazepam and cal director, review of each intubation, and strong educational lorazepam. components. If the decision is made to add RSI to an agency’s The benzodiazepines are best known for their ability to airway management options, it must be made with an effec- provide excellent amnesia. Other effects include sedation, tive monitoring program in place and with the recognition muscular relaxation, CNS relaxation, treatment of active that, if the program is not performing well, it must be stopped seizures, and anxiolysis. Midazolam may also decrease and evaluated. intracranial pressure. They work directly on a benzodiaz- epine receptor in the brain. The onset of action relates to how Medication-Facilitated quickly the agents pass into the brain, with midazolam having an onset of action of 30 to 60 seconds. The benzodiazepines and Rapid Sequence Intubation are metabolized by the liver; the half-life for midazolam is The use of medication-facilitated and rapid sequence intuba- 1.5 to 2.5 hours. tion has the potential to greatly increase a Paramedic’s ability The greatest diffi culty in using midazolam for sedation to successfully intubate a patient. To use these tools effec- is the wide variability in patient response to the agent. Doses tively, it is important to understand the medications, how they as low as 1 mg have caused apnea in some patients while function, and their indications and contraindications. The fol- others require up to 0.3 mg/kg to achieve adequate sedation. lowing covers the most important points of the medications In g eneral, male patients and elderly patients require the from the Paramedic’s perspective. smallest doses. Medication-Facilitated Intubation 477 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. The most signifi cant complication associated with mida- Other than drug allergy, there are no true contraindica- zolam is a dose-related vasodilation and myocardial depres- tions to the use of etomidate. It is not routinely used in chil- sion. Therefore, although midazolam has been routinely used dren under 10 years of age. It should be used with caution in in trauma patients and others with potential for hypotension the elderly (as should any sedative agent), and the dose can be and hypovolemia, it does pose a risk for converting a patient titrated to effect in hemodynamically unstable patients. in compensated shock to a state of decompensated shock. Etomidate is generally dosed at 0.2 to 0.3 mg/kg in Indications for midazolam, therefore, are broad, although the adult patient. A standard intubating dose in an average- it must be used with caution in the elderly and in patients at risk sized adult is 20 mg. A dose of 0.1 mg/kg is often used for for signifi cant cardiovascular decompensation. Glaucoma has procedural sedation and is a good starting point for elderly been identifi ed as a contraindication to benzodiazepine use. patients. Because there is minimal drug accumulation, it can The dosing for midazolam, because of the diffi culty in be redosed if needed. Typical time |
to onset is 1 to 2 minutes. predicting response, requires some degree of titration. The The lack of hemodynamic effects, the cerebroprotective standard dose is 0.2 mg/kg, although this varies from 0.05 effect, and the relative ease of use have made etomidate the to 0.3 mg/kg. A dose of 0.1 mg/kg, followed by additional fi rst choice of many Paramedics for trauma airway manage- doses as needed, will result in a relatively safe side effect pro- ment. It is also an excellent choice for the unstable medical fi le. The onset of action is about 2 minutes. The variability in patient. It must always be used in conjunction with a second dose response, however, may result in a patient who is under- sedative agent once the intubation is complete. sedated during paralysis. This is manifested by hypertension and tachycardia. If these hemodynamic changes are noted, Ketamine the patient should be given additional sedation. Ketamine is a dissociative anesthetic with several unique Midazolam is also useful as a post-intubation sedative. properties. A derivative of PCP, ketamine provides excellent Repeated doses of 20% to 50% of the original dose every 30 amnesia, analgesia, and anesthesia during procedures and to 60 minutes as dictated by the patient’s level of conscious- intubation. Most notably, however, it has minimal respiratory ness and cardiovascular parameters should provide excellent depression even at very high doses. In addition, it increases sedation. heart rate and blood pressure through the release of cate- cholamines. Finally, it has the pulmonary effect of reducing Etomidate bronchospasm through smooth muscle relaxation.13 Etomidate is a newer agent that functions primarily as a hyp- Ketamine’s properties have made it an excellent “spe- notic, although it also is an excellent amnestic. Its increasing cialty” sedative in airway management. Its bronchodilatory popularity in the emergency airway management setting is properties make it an excellent choice for the asthmatic because it has minimal hemodynamic effects and only mod- patient. In addition, hypotensive patients without evidence of erate respiratory depression at induction doses. In addition, it head injury benefi t from the catecholamines that are released. provides excellent relaxation and often does not require the Its effi cacy in the pediatric population is also clearly estab- addition of a paralytic to achieve an intubation, thus making lished.16 Although an IV would clearly be preferable in the it a good agent when paralysis is contraindicated.1,12 emergency airway management setting, ketamine can be Although the hemodynamic stability associated with given IM as well. etomidate is perhaps its greatest asset, it also has a cerebro- There are patients in whom ketamine is not a good agent protective effect. It both attenuates an increased ICP and for induction. Research in the early 1970s reported an increase decreases the negative effects of laryngoscopy.13 in intracranial pressure associated with the use of ketamine.17 Etomidate is not without side effects, however. Transient Although recent research brings this fi nding into question,18 muscle jerks are common and trismus has been reported.14 the current standard is to avoid the use of ketamine in patients In addition, many patients experience nausea and vomit- with head injuries or those at risk of increased intracranial ing, although this more often occurs on awakening and is pressure. In addition, the catecholamines released during ket- therefore less important in the airway management setting.15 amine administration increase myocardial oxygen demand, Finally, patients may experience burning at the site of infu- making this a poor sedative for the patient with known or sion; this can be decreased by using a large vein and a rapid suspected coronary artery disease. Drug allergy, as always, is IV fl uid rate. Etomidate, when used as a continuous drip, can also a contraindication. cause adrenal suppression. This has not been reported in the Ketamine has a number of side effects, only a few of single-dose setting of airway management. which are relevant to airway management. Increased saliva- It is important to recognize that the hypnotic effects of tion is associated with ketamine use, particularly in pediat- etomidate end approximately 20 to 30 minutes after admin- ric patients. Prior administration of atropine can minimize istration. When used with a long-acting paralytic such as this effect. Although patients usually experience relaxation vecuronium, it is critical that additional sedation (usually after ketamine administration, some will become restless in the form of a benzodiazepine) be administered after the and move purposelessly. Finally, ketamine is associated with intubation to assure that the patient is not awake and remains “emergence reactions” or hallucinations. These occur more paralyzed. commonly in adults than in children and should not be an 478 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. issue in emergency airway management as the patient will be push for sedation. If morphine is used, the Paramedic should sedated, usually with a benzodiazepine, after the intubation expect a greater hemodynamic response (e.g., hypotension). is complete. The onset of action is usually rapid (30 to 60 seconds) and Ketamine is given in doses of 1 to 2 mg/kg IV or, if given the duration of fentanyl is typically 22 to 30 minutes. Narcot- IM, 2 to 4 mg/kg. The onset of action is typically 30 seconds ics may be redosed in 22 to 30 minutes as needed. They may to a minute and can be recognized by the roving eye move- be used for short-term sedation after an intubation, although ments called nystagmus and the awake but unaware appear- longer-acting agents such as benzodiazepines are preferred. ance of the patient. The effect of ketamine typically lasts up to 10 minutes for intravenous administration and up to Neuromuscular Blocking Agents 25 minutes for intramuscular administration. (Paralytics) Although somewhat of a specialized drug, ketamine is an Neuromuscular blocking agents are medications that block important drug in the airway management of selected patients. transmission of nerve impulses to skeletal muscle at the Its minimal respiratory effects, bronchodilation, and positive neuromuscular junction. When a nerve impulse reaches the hemodynamics make it a useful medication for sedation. neuromuscular junction, the molecule acetylcholine, a neu- Fentanyl rotransmitter, is released into the synapse from the presynap- tic membrane of the nerve. The acetylcholine moves across Narcotics, a class of drugs known for their ability to induce the synapse to the postsynaptic membrane of the muscle. a profound state of sedation, as a general rule, are rarely There it binds to receptors and causes the muscle to contract used as the sole sedative agents in emergency airway man- (Figure 24-1). Normally, the contraction stops when the ace- agement. Nonetheless, they may be the only agent a prehos- tylcholine is broken down by acetylcholinesterase. pital provider has available. In addition, they are often used Skeletal muscle paralytics block the binding of ace- adjunctively in airway management, making them important tylcholine to the receptors on the postsynaptic membrane. medications with which to be familiar. Narcotics provide There are two major classes of neuromuscular blockers: analgesia and hypnosis as well as some degree of amnesia. In depolarizing agents and non-depolarizing agents. The main addition, they attenuate the increased ICP that is a refl exive difference between the two is whether the medication binds response to laryngoscopy.13 Although fentanyl is used as a to the receptor and causes a muscular contraction (a depolar- sole indication agent at very high doses (22 to 30 µg/kg) in izing agent) or simply blocks acetylcholine from binding to the operating room, lower doses of narcotics can be used in the receptor without causing the receptor to activate (a non- emergency airway management to achieve some degree of depolarizing agent). There is only one depolarizing agent that patient sedation. is commonly used (succinylcholine) while there are multiple Fentanyl is a synthetic opioid that is highly potent. It is non-depolarizing agents. known for not causing histamine release, unlike morphine. Therefore, the patient exhibits minimal hypotension when Depolarizing Neuromuscular Blockers used in small (1 to 4 µg/kg) doses. Like other narcotics, fentanyl causes respiratory depression and therefore places Succinylcholine is the most commonly used depolarizing neu- patients at risk for hypoxia and hypercarbia; this should not romuscular blocker. It is called a depolarizing agent because, be a problem during airway management as the patient will when it binds to the acetylcholine receptor on the muscle, it be continuously monitored. causes the muscle to depolarize or contract. This contraction Fentanyl, at high doses and rapid administration rates, is is limited in duration and is recognized by the Paramedic as associated with chest and abdominal wall muscular rigidity. fasciculations that occur shortly after the succinylcholine is This is an idiosyncratic reaction and results in the patient’s administered (Figure 24-2). Molecularly, succinylcholine is inability to breathe or to be ventilated. Generally speaking, composed of two acetylcholine molecules hooked back to this effect is not reversible and the patient must be paralyzed back. It is metabolized by pseudocholinesterase, an enzyme immediately. Other common effects of narcotics include nau- found throughout the body (but not actually in the neuromus- sea and vomiting. Fentanyl is often associated with an itchy cular junction). nose sensation. Succinylcholine is the most commonly used neuro- Fentanyl is indicated in the patient who may experience muscular blocker for rapid sequence intubation. It offers a signifi cant harm if there is a large catecholamine release. number of advantages over the non-depolarizing agents. Patients with acute MI, increased intracranial pressure, or vas- The two greatest assets are a rapid onset of action (30 to cular disease such as aortic dissection or aneurysm fall into 60 seconds) and rapid termination of effect (3 to 12 minutes)19 this classifi cation. In addition, any patient may benefi t from the with return of suffi cient ventilation to sustain life in 8 to analgesia and hypnosis associated with narcotics during airway 10 minutes.20 Although the duration of action is suffi ciently management, particularly if a narcotic (usually morphine) is long that a patient receiving no ventilatory support would the only agent that the Paramedic has available to her. become hypoxic,21 the short duration means that assisted Fentanyl is given in doses of 1 to 3 µg/kg slow IV push. ventilation will be needed for a much shorter time than with Morphine can be given in doses of 0.05 to 0.1 mg/kg slow IV non-depolarizing agents. Medication-Facilitated Intubation 479 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Transmitter Motor nerve cell substance (ACh) Sarcolemma Muscle cell Transmitter binding site NORMAL ACh Acetyl- cholinesterase Brief depolarization Figure 24-1 Physiology of a neuromuscular junction. Despite its possession of very desirable pharmacoki- Since succinylcholine causes muscular contraction when netic properties, succinylcholine does have a signifi cant side it initially binds to the acetylcholine receptor, the Paramedic effect profi le. Side effects of greatest importance in the pre- will see transient muscular fasciculations approximately hospital environment include fasciculations, hyperkalemia, 22 seconds after the medication is administered. These fas- and bradycardia. ciculations are associated with an increase in intragastric 480 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. succinylcholine and some other inhaled anesthetics), burns more than 24 hours old, or degenerative muscle disease. Patients with recent traumatic muscle denervation or crush DE B P L O injuries more than seven days prior should also not |
be given O L C A K RIZIN Neuromuscular succinylcholine. Finally, paralytics are contraindicated in all G blocking agents patients who cannot be face-mask ventilated in case the Para- medic is unable to intubate the patient. Depolarizing agent Succinylcholine dosing is based on the fact that very little creates an succinylcholine actually travels to the neuromuscular junc- overwhelming, tion. Since incomplete paralysis makes intubation much more persistent stimulation to receptors. diffi cult, a general rule is to use larger (rather than smaller) Membranes become doses. For an adult patient, 1.5 mg/kg of succinylcholine is exhausted and administered via rapid IV push. It can also be administered unresponsive to ACh. IM at a dose of 3 mg/kg, although it is not as predictable Acetylcholinesterase Muscle contraction in effi cacy. For children under 10, a dose of 2 mg/kg IV is Prolonged depolarization cannot recur until appropriate, and for infants and neonates, 3 mg/kg rapid IV return of resting state. push should be used. Figure 24-2 Depolarization of the Despite its signifi cant side effect profi le, succinylcholine neuromuscular junction. remains the neuromuscular blocker of choice for emergency airway management. Some thought should be given to the contraindications and side effects of the medication, but mul- pressure, intraocular pressure, and intracranial pressure. The tiple studies have demonstrated its safety and effi cacy in the increase in intragastric pressure may put the patient at risk for emergency airway management arena. regurgitation and aspiration; cricoid pressure is mandatory as soon as pretreatment medications are administered (sedatives, Non-Depolarizing (Competitive) etc.). In theory, the increase in intraocular pressure could Neuromuscular Blockers cause globe contents to herniate in the case of traumatic eye Non-depolarizing neuromuscular blockers (NMBAs) also injury. It is enlightening to note that many anesthesiologists cause paralysis through blocking acetylcholine, although still use succinylcholine without a defasciculating dose of a through a somewhat different mechanism than succinyl- non-depolarizing agent (discussed in the following text) in choline. These agents compete with acetylcholine for the the setting of open globe injuries.20 The rise in intracranial acetylcholine receptor on the postsynaptic membrane pressure of approximately 5 mmHg is of no known clinical (Figure 24-3), but do not cause the receptor to fi re. Therefore, signifi cance22 but can be blunted through pretreatment, as there are no fasciculations. The molecular model for non- will be discussed later. depolarizing neuromuscular blockers is curare. Succinylcholine administration has also been associated There are a number of non-depolarizing neuromuscular with an increase in serum potassium levels. This tends to blockers available for the Paramedic, all of which are of the happen in patients with a precipitating event (burns, neuro- aminosteroid class of NMBAs. The most commonly used muscular disease, pre-existing hyperkalemia, crush injuries, and muscle denervation). In addition, for those patients with traumatic causes, the effect is not seen for two to seven days from the event. Therefore, although the Paramedic must con- sider whether a patient is at risk for hyperkalemia, there are NO DE N few prehospital situations (other than in patients with known P - B hyperkalemia, neuromuscular disease, or in the critical care L O O L C A K RI transport environment) where the risk for hyperkalemia will ZING be important. ACh There is increased vagal tone that occurs with the a dministration of succinylcholine. Although the clinical signifi cance is low for adults after a single dose of succinyl- Non depolarizing choline, the effect can be dramatic in children, leading to agent acts to block bradycardia and even asystole. The effect is easily mitigated ACh receptor sites in an overwhelming, with pretreatment with atropine. competitive manner. There are a few absolute contraindications to the admin- No depolarization istration of succinylcholine. These include a personal or Neuromuscular family history of malignant hyperthermia (a skeletal blocking agents muscle disease that leads to a life-threatening reaction to Figure 24-3 Neuromuscular blockade. Medication-Facilitated Intubation 481 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. agent in the prehospital environment is vecuronium; other patient. A defasiculating dose is a small dose of a non- agents of this class include rocuronium, pancuronium, and d epolarizing paralytic which, when administered before rapacuronium. Although these agents have a much less sig- administering succinylcholine, prevents the fasciculations nifi cant side effect profi le than succinylcholine, they gener- associated with succinylcholine. ally have a longer time to onset at standard doses and they all The only risk associated with this technique is that the have a prolonged duration of action. Two agents, rocuronium patient may occasionally become apneic and fully paralyzed and rapacuronium, have onset of action in about 60 seconds with the defasciculating dose. The Paramedic must therefore be and rapacuronium has a duration of action that is almost the prepared to administer the full paralytic dose and intubate the same as succinylcholine.23,24 Therefore, these agents offer the patient. potential to replace succinylcholine in the emergency airway Non-depolarizing agents are also commonly used for management setting. post-intubation care. In the prehospital environment, it is Unfortunately, rapacuronium, the most promising of the usually more important that an intubated patient be protected agents (30- to 60-second onset, 20-minute paralysis without from himself and the risk of accidental self-extubation than reversal, 10-minute paralysis with reversal agent), also has it is to perform serial neurological exams. This is particularly the most signifi cant side effect profi le. important in the air medical environment where re-intubation Fasciculations, hyperkalemia, and increased intracra- can be extraordinarily diffi cult. Therefore, most prehospital nial pressure are not seen with the use of non-depolarizing patients who are rapid sequence intubated are given a full NMBAs. Therefore, in patients at risk for adverse outcomes paralyzing dose of vecuronium to minimize patient move- from those side effects of succinylcholine, a non-depolarizing ment and the risks of extubation. NMBA is the paralytic agent of choice. Since the duration of action of the vecuronium (30 to In most other cases, the delay in onset of paralysis and 60 minutes) will typically be longer than the duration of action the prolonged paralysis make these agents less desirable. of most sedatives, it is important to monitor for tachycardia Pancuronium and rapacuronium have both been associated and hypertension, both of which suggest that the patient is with tachycardia, and rapacuronium has also been associated paralyzed but not sedated. with transient hypotension and bronchospasm. vecuronium As noted, vecuronium is the most commonly used non- and rocuronium have relatively few side effects. depolarizing neuromuscular blocker used in the prehospital Neostigmine, an acetylcholinesterase inhibitor, can setting. The usual dose is 0.1 mg/kg. As mentioned, doses of be used to reverse the effects of the competitive (non- 0.3 mg/kg can be given to attain paralysis in 60 to 90 seconds, depolarizing) NMBAs. They do this by inhibiting acetylcho- but the patient will be paralyzed for up to 100 minutes. This is linesterase, the enzyme that breaks down acetylcholine. With a problem if the patient cannot be intubated and must be face- acetylcholinesterase blocker, more acetylcholine builds up in mask ventilated. At a dose of 0.1 mg/kg, the usual onset of the synapse, displacing the NMBA and decreasing recovery action is in two to three minutes. Since most sedative agents time. Although neostigmine does not instantly reverse the have an earlier onset of action, administering the vecuronium NMBA, it can cut the recovery time in half. and awaiting signs of muscular weakness before administer- There are three primary indications for the use of a non- ing the sedative may decrease the incidence of apnea before depolarizing neuromuscular blocking agent. The fi rst is a adequate paralysis occurs. paralytic patient with a contraindication to the use of succi- The non-depolarizing neuromuscular blocking agents nylcholine. The only true contraindication that succinylcho- offer many advantages over succinylcholine in terms of their line and the non-depolarizing NMBAs share is the one against side effect profi le. Unfortunately, they are limited in their use their use in patients who cannot be effectively f ace-mask ven- by their delayed onset of action and prolonged paralysis. Cur- tilated. Paralyzing a patient who can neither be intubated nor rently, they are used primarily for defasciculation and post- ventilated is truly the worst case scenario in airway manage- intubation paralysis. Newer agents with more rapid paralysis ment using RSI. It is important to note that if vecuronium and short duration of action may offer a reasonable alterna- is used for paralysis, the patient will usually become apneic tive to succinylcholine in the future. before adequate paralysis occurs and the patient will need face-mask ventilation. This problem can be mitigated if a Adjunctive Medications large (0.3 mg/kg) dose of vecuronium is used or a priming (0.01 mg/kg 2 to 3) dose of vecuronium is administered two Lidocaine and atropine are two agents that are commonly to three minutes before the intubating dose is administered. used as adjuncts to emergency rapid sequence intubation. Non-depolarizing NMBAs possess the unique ability to Both of these drugs are used to counter the effects of paralyt- block fasciculations. In doses of one tenth its intubating dose ics and of airway manipulation. (e.g., 0.01 mg/kg), vecuronium given two to three minutes before succinylcholine will prevent fasciculations and the side Lidocaine effects associated with fasciculations (increased ICP, etc.). Lidocaine, a drug thought to offer some neuroprotection, is The use of a defasciculating dose of a non-d epolarizing commonly used during the RSI of patients with head trauma, agent is most often used in the setting of the head-injured evidence of increased intracranial pressure, and bronchospastic 482 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. airway disease.25 Although there is controversy about the clin- The Paramedic should also verify the last oral intake, ical signifi cance of the effects of lidocaine, when used, it is if possible. most often used for patients with head trauma. Through a combination of deepened sedation and mul- tiple cerebral hemodynamic effects, lidocaine is thought to provide some cerebral protection for patients undergoing air- Street Smart way manipulation and may be protective against the effects of succinylcholine. In addition, lidocaine may blunt the sym- It is important that the preparation phase should be pathetic response to laryngoscopy, although this has not been the same whether the patient is undergoing intubation defi nitively demonstrated. When used, IV lidocaine at a dose of 1.5 mg/kg is administered at least three minutes before with or without pharmacological adjuncts. The administration of succylcholine. preparation step assures that “the fi rst attempt is the Atropine best attempt.” Inadequate preparation for airway management results in delays in intubation Airway management, particularly in pediatric patients under 10 years old, can cause excessive vagal stimulation. and hypoxia. Furthermore, large or multiple doses of succinylcholine put patients at risk of increased vagal tone. Therefore, atropine, a parasympathetic blocker that decreases vagal response, must be available for the treatment of these patients. In addition, atropine decreases oral secretions, an Predict the Degree of Diffi culty effect that is useful for patients sedated with ketamine or Prediction is the most important step in making the decision with excessive secretions.19 to perform a medication-facilitated or rapid sequence intuba- All patients under 5 years of age should be pretreated tion. The actual skill of intubating a person who is chemi- (two to three minutes before paralysis) with 0.2 mg/kg of IV cally paralyzed is no more diffi cult than if that person were atropine (0.1 mg < dose < 0.5 mg). In addition, any adult completely comatose with no muscle tone (i.e., a patient in patient receiving a second dose of succinylcholine should cardiac arrest). The difference |
lies in the fact that a person either be pretreated with 0.5 mg IV or atropine should be who is alive, breathing, and protecting his airway enough to immediately available if the patient becomes bradycardic. prevent intubation without medications is still alive. If the Paramedic proceeds to paralyze this patient, he takes full responsibility for the consequences of removing the patient’s The 9 P’s for Medication (limited) ability to care for himself. Therefore, extraordinary Facilitated Intubation judgment must be exercised before deciding to sedate and, more importantly, chemically paralyze a patient. The most and Rapid Sequence Intubation critical deciding factor is whether or not the Paramedic will be able to intubate the patient and, if not, provide face-mask The most commonly used tool to guide safe and effective ventilation. The guiding principle of all medical care is Pri- intubation is the rule of the “Nine P’s of RSI.” The nine mum non nocere or “fi rst, do no harm.” Chemical paralysis “P’s” are: provides the opportunity to do grave and irreparable harm to 1. Preparation a patient. 2. Predict the degree of diffi culty 3. Preoxygenate 4. Pretreat Table 24-1 Equipment List for MFI 5. Pressure on the cricoid 6. Paralyze • Continuous cardiac monitoring 7. Pass the tube • Continuous pulse-ox 8. Position (confi rm) and secure • BVM attached to 100% O2 9. Post-intubation care • Oral airway Correctly applying each of these “P’s” greatly enhances • Suction set-up the safety and effi cacy of the intubation. • ETCO2 detector/continuous monitoring ETCO2 • Ventilator attached and ready (if using) Preparation • RSI medications drawn up Preparation for medication-facilitated or rapid sequence • IV established intubation involves assuring that all necessary equipment is • Intubation equipment properly assembled and ready for use (Table 24-1). Medication-Facilitated Intubation 483 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. The need to perform an airway evaluation on all patients example, succinylcholine and etomidate have almost the before and during airway management is self-evident. Two same time of onset and therefore are administered almost tools—the LEMON law and the 3-3-2 rule—were intro- simultaneously. Midazolam, on the other hand, has a two to duced in Chapter 23. It is important to apply the LEMON law three minute time of onset and must be administered well in before any rapid sequence intubation. The Paramedic must advance of succinylcholine. As was discussed previously, if recognize when conditions exist which will prevent him or vecuronium is going to be used, it should probably be admin- her from being able to intubate the patient after paralysis. If istered before the sedative to minimize the risk of apnea. the patient’s airway is simply too diffi cult for a Paramedic’s The Paramedic must be alert during the pretreatment skill level, then the patient should not be paralyzed. phase. Some patients, particularly those who already have a In addition to assessing the diffi culty of the intuba- signifi cantly altered mental status, may become apneic after tion, however, it is also important to assess how diffi cult receiving pretreatment medications. Therefore, all equipment it will be to perform face-mask ventilation. Facial hair, for the intubation must be ready for immediate use and the facial trauma, micrognathia (small jaw), and other ana- patient closely monitored. tomic anomalies may make face-mask ventilation diffi cult or impossible. Any patient who cannot be face-mask ven- Cricoid Pressure tilated should not receive paralytic agents or sedatives in While sedative or defasciculating medications are being doses that could cause apnea. Although this may be a diffi - administered, an assistant should be assigned to apply cricoid cult decision, medication-facilitated intubation is as much pressure to minimize the risk of aspiration. A patient who has about deciding not to give the medications as it is about received sedatives will have decreased airway refl exes and giving the medications. may have a decreased lower esophageal pressure. These two factors put the patient at risk for vomiting and aspirating. Preoxygenate If the Paramedic is performing a sedation-aided intuba- It is possible to extend the time allowed for an intubation tion, the intubation attempt is made now (see the “Pass the attempt by adequately preoxygenating a patient. Adminis- Tube” section later). In addition, many providers will make tration of high fl ow oxygen for three to fi ve minutes or for an attempt at intubation before paralytics are administered if 10 to 22 deep breaths removes nitrogen from the lungs and the patient appears to be suffi ciently sedated. If the patient is replaces it with oxygen. Respiratory gasses at the level of successfully intubated with sedation alone, many of the risks alveoli include 75% nitrogen for the patient breathing room of paralysis can be avoided. air. By “washing out” the nitrogen through preoxygenation, a much larger reserve of alveolar oxygen is created. Patients Paralyze can therefore be apneic for prolonged periods (two to fi ve Once the patient has been pretreated and an appropriate time minutes) before oxygen desaturation occurs. Since hypoxia interval has passed, the paralytic agent should be given. One is so potentially damaging, this safety reserve can protect of the most signifi cant mistakes a Paramedic can make is to a patient during the prolonged apnea that can be associated attempt to intubate the patient too quickly after the paralytic with the use of sedatives and paralytics. is given. If an intubation attempt is made before the patient is completely paralyzed, not only will the patient fi ght the Pretreat attempt but the risk of aspiration is also greatly increased. Once the decision has been made to perform sedation-aided or Therefore, either a clock/watch should be used or the Para- rapid sequence intubation and the patient is preoxygenated, it medic should count out 45 seconds once succinylcholine is is important to administer any pretreatment medications that administered. No attempts to intubate should be made before will be used. Sedatives are considered “pretreatment” since then and, unless the patient desaturates, no face-mask ventila- they are used to prepare a patient for paralytics. Lidocaine, tion should be applied. If a non-depolarizing agent is used, a atropine, and defasciculation doses of non-d epolarizing similar approach of waiting for complete paralysis should be neuromuscular blockers are the other commonly used followed. pretreatment medications. Pass the Tube There is no evidence that routine use of pretreatment medications (other than sedatives) in patients without spe- Once the patient is completely paralyzed, standard methods cifi c indications (i.e., increased ICP, pediatric patients.) of oral endotracheal intubation should be used. Suction must improves patient outcomes. Therefore, atropine, lidocaine, be immediately available in the event the patient vomits. and defasciculating drugs (e.g., vecuronium 0.01 mg/kg IV) External laryngeal manipulation and/or the BURP maneuver should only be used if an indication exists. If they are going should be used to optimize visualization. to be given, they should be administered two to three minutes before the paralytic agent. Position (Confi rm) and Secure The timing of the sedative’s administration will depend Once the patient has been intubated, the tube position must be on its onset of action and the paralytic that will be used. For confi rmed with at least three methods. The paralyzed patient 484 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. is completely dependent on being ventilated. If the patient is The second important medication is a long-acting seda- esophageally intubated, he cannot continue to breathe around tive (e.g., midazolam). If etomidate is used for the intubation, the tube the way a non-paralyzed, non-apneic patient can. it will begin to wear off in 10 to 20 minutes after administra- Therefore, confi rmation must be rapid and accurate. The para- tion. Although other sedatives (e.g., midazolam, ketamine) lyzed patient is also at risk for complications from a displaced may have a longer duration of action, their duration will still tube, particularly after receiving post-intubation sedation and be less than that of vecuronium. Therefore, the patient should paralysis. Use of continuous end-tidal carbon dioxide moni- be monitored for signs (tachycardia and hypertension) of toring decreases the risk of a missed displaced tube. inadequate sedation. Properly securing the endotracheal tube also decreases the risk of tube dislodgment. Any method is acceptable as long as it prevents the endotracheal tube from moving. The Street Smart depth of the endotracheal tube at the lips should be noted and recorded to verify that there is no tube movement. The neck should be secured with a cervical collar to prevent fl exion The Paramedic will recognize that induced paralysis and extension and the patient should be secured to a long- does not alter sensation. The patient is acutely aware spine board for transport. of noise, lights, odors, pain, and other sensations Post-Intubation Care such as pressure. These stimuli should be reduced Once the patient has been successfully intubated and the tube or eliminated by altering the environment or is secured, there are several important post-intubation tasks administering appropriate medications. to be performed. All patients who are intubated should have a nasogastric or orogastric tube placed to allow active or pas- sive decompression of the stomach. This is particularly true The Paramedic should be aware and monitor for signs of for pediatric patients who can suffer signifi cant respiratory malignant hyperthermia. This is a genetic muscular disease compromise from gastric infl ation. that affects some people after receiving inhaled anesthetics There are also two important post-intubation medications or succinylcholine. Signs of malignant hyperthermia include that should be administered. The fi rst important medication to fever, muscular rigidity (as opposed to being fl accid), tachy- administer is a long-acting non-depolarizing neuromuscular cardia, and tachypnea. Although most EMS providers will blocker, generally vecuronium. As was discussed previously, not have access to Dantrolene, the medication used to treat post-intubation paralysis decreases the risk of accidental malignant hyperthermia, the patient can be cooled with cold extubation. If vecuronium was used to perform the intuba- packs and exposure. In addition, the receiving facility should tion, it is not necessary to administer a second dose. be notifi ed of the patient’s condition. Medication-Facilitated Intubation 485 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Medication-facilitated and rapid sequence intubation offer the Paramedic an expanded range of tools for patient care. Patients who could not previously be intubated can receive the benefi ts of translaryngeal endotracheal intubation. These medications, however, are not without side effects and their use is associated with complications. The actual acts of administering the medications and performing the intubation are no different than in any other patient. The most critical difference, particularly for the use of paralytics, is the judgment required to make the initial decision to paralyze the patient. Chemical paralysis cannot be done lightly or without forethought; it is an intervention with the potential to kill a patient. Nonetheless, there are clear benefi ts to performing rapid sequence intubation and therefore the Paramedic should be familiar with the procedure. Key Points: • The most important factors in the success of RSI minimal hemodynamic effects and only moderate programs have been the involvement of an active respiratory depression at induction doses. medical director, review of each intubation, strong Etomidate also attenuates an increased ICP and educational components, and |
an overall effective decreases the negative effects of laryngoscopy. monitoring system. Side effects may include transient muscle jerks • and trismus. Many patients experience nausea and The use of pharmacological agents to facilitate vomiting upon awakening. intubation can be thought of as those that provide sedation and those that cause muscular paralysis. • Ketamine is a dissociative anesthetic that provides In addition, adjunctive medications that are often excellent amnesia, analgesia, and anesthesia during used in RSI include vagolytics (atropine) and procedures and intubation. Ketamine also has minimal lidocaine. respiratory depression; it increases heart rate and • blood pressure through the release of catecholamines Sedative agents are medications that are used to and has the pulmonary effect of reducing decrease a patient’s level of consciousness, effect bronchospasm through smooth muscle relaxation. It muscular relaxation, and cause amnesia to the should be avoided in the head-injured patient. intubation. Four of the most commonly used agents are midazolam (a benzodiazepine), etomidate, • Narcotics provide analgesia and hypnosis as well ketamine, and fentanyl (a narcotic). as some degree of amnesia. In addition, they • attenuate the increased ICP that is a refl exive Midazolam, a short-acting benzodiazepine, has an response to laryngoscopy. Lower doses of narcotics onset of action of 30 to 60 seconds and a half-life can be used in emergency airway management to of 1.5 to 2.5 hours. achieve some degree of patient sedation. • Response to midazolam varies widely. In general, male patients and elderly patients require the smallest • Fentanyl is a synthetic opioid that is highly potent doses. The most signifi cant complication associated and has minimal hemodynamic effects. Like with midazolam is the development of shock. other narcotics, it causes respiratory depression. It may be indicated in the patient who may • Etomidate is a newer agent that functions experience signifi cant harm if there is a large primarily as a hypnotic and amnestic. It has catecholamine release. 486 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. • Neuromuscular blockers prevent transmission (5) pressure on the cricoid, (6) paralyze, (7) pass the of nerve impulses to skeletal muscle at the tube, (8) position (confi rm) and secure, and (9) post- neuromuscular junction by either binding to intubation care. the receptor, causing a muscular contraction (a depolarizing agent), or simply blocking • To prepare for medication-facilitated or rapid acetylcholine from binding to the receptor sequence intubation, and to assure the “fi rst without causing the receptor to activate (a non- attempt is the best attempt,” the Paramedic depolarizing agent). should ensure all necessary equipment is properly assembled and ready to use. • Succinylcholine is a depolarizing agent. It binds to the acetylcholine which binds to the receptor, • Predicting the degree of diffi culty is the most causing the muscle to contract, and then prevents important step in making the decision to perform further contractions. a medication-facilitated or rapid sequence intubation. • Contraindications for succinylcholine include a personal or family history of malignant • Preoxygenation of the patient is performed by hyperthermia, burns more than 24 hours old, administering high fl ow oxygen for three to fi ve degenerative muscle disease, and crush injuries minutes or for 10 to 22 deep breaths. This removes more than seven days prior. nitrogen from the lungs and replaces it with oxygen • which can extend the time allowed for an intubation Paralytics are contraindicated in all patients attempt. who cannot be face-mask ventilated in case the Paramedic is unable to intubate the patient. • Pretreatment medications—lidocaine, atropine, • and defasciculating doses of non-depolarizing Vecuronium, rocuronium, pancuronium, and neuromuscular blockers—should be given two to rapacuronium are non-depolarizing agents that do three minutes before the paralytic agent. not cause fasciculations. These agents generally have a longer time to onset at standard doses and • While sedative or defasciculating medications are they all have a prolonged duration of action. being administered, a patient care provider should • apply cricoid pressure to minimize the risk of Neostigmine inhibits acetylcholinesterase, allowing aspiration. more acetylcholine to build up in the synapse, displacing the NMBA and decreasing recovery time. • Once the patient has been pretreated and an • appropriate time interval has passed, the paralytic A non-depolarizing neuromuscular blocking agent is agent should be given. Once succinylcholine commonly used to block fasciculations through a low is administered, no face-mask ventilation should be dose administration called a defasciculating dose. applied and the Paramedic should count out • Lidocaine and atropine are used to counter the 45 seconds before attempting to intubate. effects of paralytics and of airway manipulation. • After paralysis is achieved, standard methods of oral • Airway management, particularly in pediatric endotracheal intubation should be used. patients under 5 years old, can cause excessive vagal stimulation, primarily bradycardia. • Following intubation, tube position must be confi rmed rapidly and accurately with at least • The most commonly used tool to guide safe and three methods. Standard methods for securing the effective intubation is the rule of the “Nine P’s of RSI.” tube are then performed, and continuous end-tidal The nine “P’s” are (1) preparation, (2) predict the carbon dioxide monitoring is used to monitor for degree of diffi culty, (3) preoxygenate, (4) pretreat, tube displacement. Medication-Facilitated Intubation 487 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Review Questions: 1. What two general categories of medications 8. List two reasons why succinylcholine is exist for airway management? used preferentially to non-depolarizing 2. What are the key differences between the NMBAs. following sedative agents: midazolam, 9. Name two adjunctive medications for RSI and etomidate, ketamine, and fentanyl? give their indications. 3. What is the mechanism of action of a 10. What are the “Nine P’s of RSI”? depolarizing neuromuscular blocking agent 11. How should the Paramedic assess the airway (NMBA)? for medication-facilitated and rapid sequence 4. What is the mechanism of action of a non- intubation? depolarizing NMBA? 12. Explain the protective effect of preoxygenation. 5. How does neostigmine affect neuromuscular 13. Identify two post-intubation medications and blockade? explain why they are used. 6. Describe four side effects of succinylcholine. 7. Explain the difference between a “defasciculating” and a “paralytic” dose of a non-depolarizing NMBA. Case Study Questions: Please refer to the Case Study at the beginning 3. Approximately 15 minutes into the fl ight, the of the chapter and answer the questions below: fl ight medic observes an increase in heart rate 1. List at least three reasons for using medications and blood pressure. What might cause this during intubation of this patient. response? What actions are indicated? 2. What adjunctive medications are indicated for this patient? Why? 488 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. References: 1. Bozeman WP, Young S. Etomidate as a sole agent for 14. Chohan N, ed. 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Ochs M, Davis D, Hoyt D, Bailey D, Marshall L, Rosen P. 21. Benumof JL. Succinylcholine duration and critical Paramedic-performed rapid sequence intubation of patients with hemoglobin desaturation in the healthy adult. Anesthesiology. severe head injuries. Ann Emerg Med. 2002;40(2):159–167. 1998;88(6):1686–1688. 9. Winchall RJ, Hoyt DB. Endotracheal intubation in the fi eld 22. Storer DL. The pharmacology of airway control. Emerg Care Q. improves survival in patients with severe head injury. Trauma 1991;7(1):64. Research and Education Foundation of San Diego. Arch Surg. 23. DeMay JC, Debrock M, Rolly G. Evaluation of the onset and 1997;132(6):592–597. intubation conditions of rocuronium bromide. Eur J Anesthesiol 10. Karch SB, Lewis T, Young S, et al. Field intubation of trauma Suppl. 1994;9 (Suppl):37–40. patients: complications, indications, and outcomes. Am J Emerg 24. Fleming NW, Chung F, Glass PS, et al. Comparison of the Med. 1996;14(7):617–619. intubation conditions provided by rapacuronium (ORG9487) or 11. Dickinson ET, Cohen JE, Mechem CC. The effectiveness succinylcholine in humans during anesthesia with fentanyl and of midazolam as a single pharmacologic agent to facilitate propofol. Anesthesiology. 1999;91(5):1311–1317. endotracheal intubation by Paramedics. Prehosp Emerg Care. 25. Schneider R. Drugs for special clinical circumstances. In: 1999;3(3):191–193. Walls R, et al., eds. Manual of Emergency Airway Management. 12. Reed DB. Regional EMS experience with etomidate for Philadelphia: Lippincott, Williams, and Wilkins; 2000: facilitated intubation. Prehosp Emerg Care. 2002;6(1):50–53. 135–139. 13. Schneider R. Sedatives and induction agents. In: Walls R, et al., eds. Manual of Emergency Airway Management. Philadelphia: Lippincott, Williams, and Wilkins; 2000:129–139. Medication-Facilitated Intubation 489 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. KEY CONCEPTS: Upon completion of this chapter, it is expected that the reader will understand these following concepts: • The formation of acid from respiratory and metabolic mechanisms and physiological pH • Three important chemical buffers found in the bloodstream • Respiratory and renal compensation by deriving the acid–bicarbonate formula • Acidosis as an imbalance Case Study: The Paramedics were called to the local community college for an instructor suffering an acute asthma attack. Mr. Byrnes had a lengthy history of asthma beginning in high school. His last attack, four months ago, had required intubation and two days on ventilatory support. The nurse in the health offi ce had placed Mr. Byrnes on oxygen along with monitoring pulse oximetry. He had tried to use his rescue inhaler but could not take deep enough breaths. Even though his pulse oximetry reading was |
at 97%, one look indicated that he was laboring, tachypneic, and fearful. 490 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Ventilation 491 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. OVERVIEW Ventilation is more than just the movement of air in and out the lungs. For the Paramedic, examining ventilation involves understanding the physiology of gas exchange and the different ways the body maintains a balanced pH. Metabolically, the body’s organs work together to maintain an acid−base balance. This chapter examines the basic chemistry of pH, the chemical buffers, and how ventilation provides a fi rst line of defense from acid imbalance. Respiratory and renal mechanisms also play an important role by driving the acid–bicarbonate formula, which works to regulate pH. Respiratory acidosis is seen as an imbalance that the Paramedic can recognize and treat. Respiration and Oxygen is an ineffective method for carrying oxygen to the tissues because oxygen does not easily dissolve into liquid and Transportation only a small amount of oxygen can be delivered. A more The term “respiration” has several defi nitions applicable to effective mechanism for oxygen transport involves binding Paramedic practice.1 The fi rst defi nition of respiration is the the oxygen molecules directly to a compound or structure movement of respiratory gasses in and out of the lungs. As within the blood for transportation to the tissues. This trans- discussed in Chapter 16, one respiration is the cycle of inspi- port mechanism is responsible for the other 97% of oxygen ration and expiration which moves air in and out of the lungs. transported to the tissues and involves red blood cells and On a cellular level, respiration is defi ned as “the chemical the hemoglobin molecule that makes up the majority of the processes by which an organism supplies its cells and tissues red blood cell. with the oxygen needed for metabolism and relieves them of Each red blood cell contains approximately 270 mil- the carbon dioxide formed in energy-producing reactions.” lion hemoglobin molecules. Each hemoglobin molecule can Respiration includes everything from inspiration, movement normally bind up to four oxygen molecules (Figure 25-3). of oxygen into the bloodstream, absorption of oxygen into When the hemoglobin molecule attaches at least one oxygen the cells, utilization of oxygen to make energy, the movement molecule, it is called oxyhemoglobin. The hemoglobin mol- of carbon dioxide to the bloodstream and ultimately across ecule that is not attached to any oxygen molecules is called into the air in the alveoli, and the exhalation of carbon diox- deoxyhemoglobin. As oxygen attaches to each of the binding ide into the atmosphere (Figure 25-1). Through this process, sites, the shape of the hemoglobin molecule opens up around the human body is able to live and function. the other oxygen-binding sites, making it easier to bind oxy- The components of this process that the Paramedic can gen to the next site. Due to this property, it takes a smaller affect during the breathing step in the resuscitation involve increase in partial pressure of oxygen (see the discussion on several actions that improve oxygenation and ventilation. partial pressures in Chapter 20) to saturate the hemoglobin Before we can assess those components, let’s review how the molecules with oxygen when hemoglobin is in the deoxyhe- body transports oxygen and carbon dioxide. moglobin state. As hemoglobin nears complete saturation, it then takes a larger change in partial pressure of oxygen to fully saturate all oxygen-binding sites. Figure 25-4 demon- Oxygen Transport strates this relationship between partial pressure of oxygen Oxygen comprises 21% of room air. As discussed in Chap- and hemoglobin saturation. It should be noted that arte- ter 20, the fraction of inspired oxygen, FiO , can be increased rial blood typically has a saturation of approximately 97%, 2 by providing supplemental oxygen to the patient through one whereas venous blood will typically have a oxygen saturation of several oxygen delivery devices. Inspiration fi lls the lungs of approximately 75%.2 with oxygen-rich air. Oxygen diffuses across the alveoli and There are several factors that affect oxygen’s ability to capillary wall because of the higher concentration of oxygen bind to hemoglobin. Some of these factors are used by the in the alveoli compared with the lower concentration of oxy- body to enhance the release of oxygen as part of normal gen in the blood surrounding the alveoli (Figure 25-2). transport, whereas others occur when the body is ill or injured Oxygen is transported to the tissues by two different (Table 25-1). The factors that increase oxygen binding in mechanisms. Approximately 3% of oxygen that enters the effect shift the curve in Figure 25-4 to the left. By shifting the bloodstream is dissolved into the plasma, or liquid portion curve to the left, it takes a smaller change in partial pressure of the blood, similar to the way carbon dioxide is dissolved of oxygen to increase the saturation of the hemoglobin. Con- into liquid to produce the fi zz in carbonated beverages. This versely, the factors that decrease oxygen binding move the 492 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Inhalation Exhalation Oxygen moves into bloodstream O2 CO2 O2 CO O 2 2 CO O2 2 O2 O2 Movement of CO2 into alveoli Capillary bed O2 O2 O2 Absorption of oxygen into cells CO2 CO2 Figure 25-1 The process of respiration. Hemoglobin O2 O2 O Oxygen molecule 2 Red blood cell O2 O2 O Alveoli 2 O2 O2 O2 O2 O2 O O 2 2 O2 O2 Hemoglobin carries O2 oxygen throughout O2 the body Pulmonary capillaries Figure 25-3 Red blood cells contain hemoglobin, the oxygen-carrying portion of the Figure 25-2 Oxygen movement across the blood, which can transport up to four oxygen alveoli–capillary membrane. molecules per hemoglobin molecule. Ventilation 493 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Dissolved O2 100 (Total O2) 20 90 Normal P 18 O2 80 16 70 14 60 12 O2 Combined 50 with Hb 10 40 8 30 6 20 4 10 Dissolved O2 2 0 0 10 20 30 40 50 60 70 80 90 100 PO2 (mm Hg) Figure 25-4 The oxygen–hemoglobin dissociation curve. In the lower portion of the curve, it takes a small increase in partial pressure of oxygen to produce a large increase in oxygen saturation. Table 25-1 Factors That Affect the Ability Temperature also affects hemoglobin’s ability to off-load to Bind Oxygen to Hemoglobin oxygen at the tissues. Decreased temperatures shift the curve to the left while increased temperatures will shift the curve to Increased Decreased the right. This is why patients who have sustained traumatic • Alkalosis • Acidosis injury, who are often cold from exposure, even in warmer cli- • Decreased CO2 • Increased CO mates, should be kept warm and provided with supplemental 2 • Decreased temperature • Increased temperature oxygen to compensate for the diffi culty in off-loading oxygen • Decreased 2,3-BPG • Increased 2,3-BPG as a result of decreased body temperature. Once the hemoglobin circulates to the tissues, some of the oxygen bound to hemoglobin dissociates, or is released, from the hemoglobin into the blood and taken into the cells. curve to the right, requiring a larger change in partial pres- The environment in the capillary blood has a lot of the fac- sure of oxygen to saturate the hemoglobin molecules. tors that enhance oxygen release from hemoglobin, including Both alkalosis and acidosis will be discussed later in this increased carbon dioxide and increased levels of 2,3-BPG. chapter. Alkalosis will cause a shift in the curve to the left, In the cell, oxygen is used with glucose to produce energy increasing the affi nity of hemoglobin to oxygen, and acidosis to carry out the cell’s functions (e.g., contraction for muscle will cause a shift in the curve to the right, decreasing the affi n- cells, chemical production for an endocrine cell, or to fi ght ity of hemoglobin for oxygen. This change in affi nity helps bacterial invaders). the hemoglobin either hold on to the oxygen molecules or enhances the release of oxygen molecules from hemoglobin. Carbon Dioxide Transport A second way the body enhances release of oxygen from Carbon dioxide is a by-product of cellular respiration. During hemoglobin is through a compound called 2,3-BPG. 2,3-BPG the chemical processes within the cell, oxygen and glucose occurs naturally in the hemoglobin, enhancing the release of are used to produce energy for the cell. Carbon dioxide and oxygen from hemoglobin at the tissues to provide oxygen for water are produced as waste products of this reaction. The the energy production process at the cellular level. This com- carbon dioxide diffuses across the cell membrane and into pound can be found in higher concentration in situations where the blood. Once in the blood, some carbon dioxide is taken the amount of oxygen inhaled into the lungs is decreased or in up and carried to the lungs in the red blood cells while some conditions where there is chronic tissue hypoxia. This is a way stays dissolved in the plasma. for the body to compensate for less available oxygen at high alti- Carbon dioxide is 20 times more soluble than oxygen in tudes or for advanced chronic respiratory conditions. Increased the blood at the same partial pressure, and much of the car- production of 2,3-BPG helps to prevent hypoxia in the tissues. bon dioxide transported by the blood is dissolved within the 494 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. % Hb Saturation O2 Content mL/100 mL (vol%) plasma. Some of the dissolved carbon dioxide is then absorbed couple with other molecules, even if it means uncoupling into the red blood cells and then released back into the blood one chemical molecule from another and bringing about the as bicarbonate, which is then transported to the lungs. A small destruction of the molecule compound in order to allow the amount of carbon dioxide travels back to the lungs attached hydrogen to attach, or bond, with another chemical. to the hemoglobin molecules, at a different site from the oxy- In some cases, a molecule may be negatively charged, gen molecules, and some carbon dioxide molecules combine such as the hydroxyl molecule (OH). These chemicals are with other compounds in the blood. Therefore, carbon diox- called bases and bases lack a proton and want to accept the ide is transported to the lungs in one of three ways: dissolved protons from acid |
in order to become electrically balanced. in the blood plasma, attached to hemoglobin, or contained For example, if an acid (H) was to join with a base (OH), with bicarbonate. the result would be water (H O). The acid is then said to be 2 At the lungs, the bicarbonate is changed back to carbon buffered, or rendered neutral (i.e., not having an electrical dioxide and water. The dissolved carbon dioxide off-gasses charge) once it combined with a base to form water. and the hemoglobin releases its carbon dioxide. The carbon Trying to describe the different amounts of acidity or dioxide then diffuses across the alveolar membrane and into alkalinity in a solution can be diffi cult, since there can be as the alveolar air, ready for exhalation. The transport of car- much as a thousand-fold difference from one extreme to the bon dioxide is affected by many factors including both the other. Practically speaking, using such a range is diffi cult. To amount of carbon dioxide produced by the cells (metabolism ease the process of describing the strengths of acids and rate) and the amount of blood volume circulated through bases, the pH scale (abbreviated for potential hydrogen) was the lungs. If the patient is hypotensive, there is less blood developed to describe the differing degrees of acidity or alka- circulating through the lungs and reduced transportation of linity. Mathematically, pH is the negative logarithm of the carbon dioxide to the lungs. Similarly, if the patient has hem- hydrogen ion concentration (pH log10[H]). The range orrhaged than there are fewer red blood cells, which means of pH is from 0 to 14, with 7 being neutral; pure distilled less hemoglobin to bind oxygen and plasma to carry the car- water is neutral. A weak acid has a pH closer to 7, somewhere bon dioxide. in the range of 5 to 7, whereas a weak base has a pH some- These factors culminate to increase carbon dioxide levels where in the 7 to 9 range. Human blood has a pH of 7.35 in the tissues. Carbon dioxide, together with water, forms a to 7.45, and is slightly alkaline. When the concentration of weak acid called carbonic acid (H CO ). The level of carbonic hydrogen ions increases, the solution becomes more acidic, 2 3 acid in the body is referred to as the “acid load.” and the pH decreases. When the concentration of hydrogen During any form of shock there is an increase in the ions decreases, the solution becomes more basic, and the pH body’s acid load. An increased acid level in the body can have increases (Figure 25-5). devastating effects to the normal metabolic functions of the Excessive amounts of acid in the tissues, in sum total body if not corrected. called an acid load, can be devastating to proteins within the cells. Excess acid can eventually break down (i.e., dena- Acid–Base Balance ture) proteins in the cells and eventually lead to cell death or necrosis. Acids are created in the course of both aerobic (with oxygen) Acid is eliminated from the interstitial space when the and anaerobic (without oxygen) metabolism. The majority of acid dilates the capillary beds. The acid passes into the capil- acid in the body is formed when excess carbon dioxide reacts lary bed and the acid is washed out in the blood. Upon enter- with water to form carbonic acid (H CO ) before conversion 2 3 ing the bloodstream, the acid can now be acted upon by the into bicarbonate. It is called the respiratory acid as it is the body’s buffering mechanisms. intermediary step in carbon dioxide transport. Other acids (e.g., lactic acid and pyruvic acid formed during anaerobic metabolism, and amino acids formed by the breakdown/ Buffering Systems oxidation of proteins) are called the metabolic acids. Regard- Any acid, whether metabolic or respiratory, entering the less of the source, an overabundance of acid can interfere bloodstream immediately encounters the three chemical buf- with the normal enzyme action within the cells.Acid levels fers that circulate throughout the body in the bloodstream. must be controlled by the body. Bicarbonate (HCO –), the most common chemical buffer, 3 An acid, by defi nition, is a molecule that has a proton almost instantaneously couples and neutralizes the acid (a positively charged atomic particle) that is not orbited by a (H), releasing heat in the process. The result is carbonic paired negatively charged atomic particle called an electron. acid (H O ). Carbonic acid then reverts into water (H O) and 2 3 2 The particle that exists in nature with one proton is the hydro- carbon dioxide (CO ) in the lungs. The water (H O) is then 2 2 gen particle and thus hydrogen is considered a primary acid. either absorbed or excreted by the kidneys and the carbon And acids are chemical compounds with positively charged dioxide (CO ) is exhaled in the breath. 2 hydrogen (H) particles or ions attached; ions being charged While bicarbonate is a powerful buffer, the amount of particles. Being positively charged, these hydrogen ions are bicarbonate in the bloodstream is limited and only provides extremely reactive, meaning that the hydrogen ion wants to approximately one half of the blood buffering capacity. Ventilation 495 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. [OH– 100 10–1 10–2 10–3 10–4 10–5 10–6 10–7 10–8 10–9 10–10 10–11 10–12 10–13 10–14 ] [OH–] Neutral [ H+ ] = [OH–] Increasing alkalinity Increasing acidity OH– H+ [H+] 10–14 10–13 10–12 10–11 10–10 10–9 10–8 10–7 10–6 10–5 10–4 10–3 10–2 10–1 100 [H +] pH 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 pH Oven Milk of cleaner Magnesia Coffee Lemon juice; (pH 13.5) (pH 10.5) (pH 5) gastric juice (pH 2) Urine Grapefruit (pH 5-8) Household juice (pH 3) ammonia Saliva; milk Sauerkraut (pH 11.5-11.9) (pH 6.5) (pH 3.5) Household Distilled Tomato juice bleach (pH 12) water (pH 7) (pH 4.2) Human blood; semen (pH 7.4) Egg white (pH 8) Saltwater (pH 8.4) Figure 25-5 pH scale with common acids and bases shown. Another chemical buffer, phosphate (PO ), also helps to buf- metabolism, there are two other ways the body can compen- 4 fer acids. Phosphate buffers bind with acid and carry the acid sate for increased acid production. Both respiratory compen- to the kidneys to be excreted, thus making urine acidic. sation and renal compensation kick in during times when the Finally, the proteins in the blood have a limited ability to body is producing additional acids, whether through increased buffer acid. All blood proteins, including albumin the most metabolic load, disease, or lack of oxygen. The three means of abundant blood protein, are made of chains of amino acids. buffering—chemical, respiratory, and renal—are interlinked These amino acids became neutralized when bonded in chains, and any weakness in one is compensated for by the others. but these proteins are capable of accepting more acids. There- fore, albumin is important to helping maintain an acid–base Respiratory Compensation balance. Albumin is so important that patients who have liver The lungs also have an ability to help rid the body of acid by disease, and subsequently reduced albumin, are more likely to driving the acid–bicarbonate formula. The acid–bicarbonate have problems with maintaining acid–base balance. reaction is easily reversible, releasing acid back into the blood- Blood proteins also include the hemoglobin molecules stream in the form of carbonic acid (H CO ) (Figure 25-6). 2 3 contained within the red blood cells (erythrocytes). Hemo- Sensitive central chemoreceptors monitor cerebrospinal fl uid globin can preferentially bind to either oxygen (O ) or acid (CSF) for an increase in carbonic acid, the respiratory acid, 2 (H), and therefore it releases its oxygen at the capillary and stimulate the medulla to increase respirations. Increased level and picks up acid at the venous side for removal in the respirations increase removal of carbon dioxide and drive the lungs or kidneys. Patients who have lost large volumes of formula to the left, forcing the conversion of acids into bicar- blood will have diffi culty with maintaining an acid–base bal- bonate, then carbon dioxide and water, which are removed ance because they have lost hemoglobin. through ventilation and urination. This process of increasing In addition to the chemical buffering that occurs to the respiratory rate in response to increased acidity of the cere- handle the day-to-day production of acids in response to bral spinal fl uid occurs rapidly, within several minutes. 496 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. H H H – the environment is slightly more acidic than in the central cir- + O C O + O C C H H O O O + O H culation. The process of cellular respirartion starts with meta- O O bolically active cells. These cells produce acid as one of the Carbon dioxide Water Acid Carbonic acid Bicarbonate by-products of metabolism. These cells also need more oxygen to sustain their aerobic (with oxygen) metabolism. The acid Figure 25-6 The acid–bicarbonate reaction. causes the capillary beds to dilate, permitting more oxygen- Increased ventilation forces this chemical carrying hemoglobin red blood cells in the blood to enter the equation to move to the left, increasing capillary. Once the blood is in the capillary bed, and in the production of carbon dioxide and water, which are presence of the acid, the oxygen is released from the hemoglo- then removed from the body. bin and moved into the cells. The use of oxygen in the cell is a process called cellular respiration. Renal Compensation A problem occurs when the blood in the central circula- tion becomes acidotic from a large “acid load” developing In the triad of buffering systems, the kidneys are the last within the body. Under normal conditions the acid in the line of defense. When carbonic acid reaches the kidneys, an blood, as carbonic acid, changes to carbon dioxide, diffuses in enzyme called carbonic anhydrase (an- – “without”, hydra – the alveoli, and is exhaled. With the acid eliminated from the “water”, -ase – “enzyme”) breaks the carbonic acid down into blood, the oxygen in the alveoli can be attached to hemoglo- bicarbonate (HCO –) and acid (H). The acid is excreted in 3 bin and carried out to the capillary beds. If the acid load in the the urine. In the process, the bicarbonate (HCO –) is regener- 3 central circulation is too great (e.g., secondary to hypoventi- ated for use in the bloodstream. The kidneys also can create lation or an increase in metabolic acids), then the oxygen will ammonia from the breakdown of the amino acid glutamine not be released into the tissues and the patient may experi- by the enzyme glutaminase, an enzyme that works best in an ence hypoxemia. Due to the effect of acid and temperature on acidic environment. Ammonia (NH ) then couples with acid 3 the oxyhemoglobin curve described in Figure 25-4, the oxy- (H) to become ammonium (NH ) and is excreted in the 4 gen saturation of a patient who has a fever or who has a large urine. Ammonium is a volatile acid, meaning that it off- gasses acid load, as is the case with a septic patient from a severe into the atmosphere and gives urine its distinctive odor. infection, will be lower than expected. The oxygen saturation This process of enzyme activation, reabsorption of bicar- may remain lower than expected despite the presence of high- bonate, and excretion |
of acids can take up to 49 hours to fully fl ow oxygen via nonrebreather face mask until the underlying activate. For this reason, compensation by the kidneys is inef- metabolic cause—in this case, the infection—is treated. fective during an acute emergency. Renal compensation only comes into action in patients who are chronically ill or who Acidosis and Medication have been acutely ill for several days. Acidosis, excessive acid in the system, can have a profound Effects of an Acidic Environment effect upon the body’s uptake, distribution, and the effectiveness The effi ciency of all of the body’s chemical processes, of medications administered by the Paramedic as well. Once a whether in the bloodstream, within the cells, or in the space medication is in the bloodstream and enters the interstitial space between the cells, depends on the local pH where the process it must cross the cell wall, a lipid–protein matrix. This semiper- takes place. If the local environment becomes too acidic or meable membrane readily accepts those medications that are not too basic, the chemical process may not occur at all. Trans- ionized (i.e., did not dissolve in solution). These “lipid-soluble” port of materials across cell membranes may also not occur medications easily diffuse across the lipid–protein cell mem- if the pH of the blood is too far outside the normal range. brane (i.e., “like dissolves like”). The problem occurs when a This can affect important body functions (e.g., produce car- medication enters the bloodstream and is dissolved, meaning diac dysrhythmias, affect oxygen transport, and affect muscle the medication becomes divided into two charged or “ionized” strength). Two important areas pertaining to Paramedic prac- portions. Some medications start as a salt and then dissolve in tice are oxygen transport and the effect of medications. solution to become ionized as either a weak acid or weak base. These ionized (charged) medications are repelled by the cell Acidosis and Oxygen Transport membrane and are called lipophobic (lipo- – “fat”, phobic – “fear”) medications. Lipophobic medications require carriers or As discussed earlier in this chapter, oxygen is picked up by the other compounds (e.g., bicarbonate or an amino acid) to carry hemoglobin in the red blood cells and transported to the tissues the medication into the cell. When the surrounding tissues are where it is released and used to produce energy. Hemoglobin’s acidotic, the medication is not dissolved normally and absorp- attraction, or affi nity, for oxygen is due to the iron molecules tion is reduced, thus reducing the drug’s effi ciency. that make up the hemoglobin. However, acids have a greater affi nity for oxygen. When acid is present, it will cause oxygen to separate (dissociate) from the hemoglobin. This phenom- Acid–Base Disorders enon, called the Bohr effect, is responsible for oxygen entering Changes in the acid–base balance in the body can have dra- the tissues at the cellular level in the interstitial space, where matic effects on the patient’s signs, symptoms, physiology, Ventilation 497 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. and the effects of medications on the patient. Even in the brief and ventilation. This may include administration of supple- patient contact time as part of many EMS calls, the Paramedic mental oxygen or invasive airway management maneuvers as can detect subtle signs of these derangements and initiate discussed in previous chapters. treatment that can prevent or slow catastrophic deterioration in the patient’s condition. These disorders are typically identi- fi ed through either an arterial blood gas or a venous blood gas, Metabolic Acidosis where a blood sample from either an artery or a vein is analyzed During metabolism, the body makes acids other than carbon for the pH, the partial pressures of carbon dioxide and oxygen dioxide. These metabolic acids can cause systemic acidosis (pCO and PO ), the bicarbonate, and the oxygen saturation. as well. The quintessential example of metabolic acidosis is 2 2 These parameters are examined to assess for an acid–base dis- the patient experiencing diabetic ketoacidosis. During hypo- order. While the interpretation of arterial and venous blood gas glycemic conditions, the body breaks down fats for energy is outside the scope of the typical street Paramedic, there are and produces ketonic acids in the process, leading to ketoaci- several causes for each and associated signs and symptoms. dosis, or ketonic acids in the blood. Other causes of metabolic The blood can either become acidotic if the pH falls acidosis include cyanide poisoning and carbon monoxide poi- below 7.35 or alkalemic if the pH rises above 7.45. Each of soning. Both of these conditions deprive the cells of oxygen these main disorders has respiratory causes and metabolic and force anaerobic (without oxygen) respiration. causes for the acidosis and alkalosis. Therefore, the four main While too much lactic acid, pyruvic acid, or ketonic acid acid–base disorders, in order of most common to least com- can produce metabolic acidosis, the absence of bicarbonate mon for Paramedics, are respiratory acidosis, metabolic aci- can also result in a relative metabolic acidosis. Under normal dosis, metabolic alkalosis, and respiratory alkalosis. conditions, the kidneys and the bowels reabsorb bicarbonate, making it available for reuse. Therefore, any gastrointestinal Acidosis or urinary disease can cause serious problems with maintain- ing acid–base balance. For example, the gallbladder secretes The blood becomes acidotic if the pH falls below 7.35. As bicarbonate to neutralize the acid created by the stomach. previously discussed, the blood in the capillaries is slightly This bicarbonate is then reabsorbed in the intestines. When more acidotic than the blood in the central circulation, which massive or persistent diarrhea occurs, then the intestines can- assists in the off-loading of oxygen and removal of carbon not reabsorb the bicarbonate. When a patient experiences dioxide from the tissues. Acidosis can occur as a result of renal failure, the kidneys cannot absorb the bicarbonate that either problems with the respiratory acids or the metabolic is excreted into the urine. The patient may become acidotic acids. It is possible to have a mixed respiratory and metabolic from the lack of the bicarbonate buffer. cause for a patient’s acidosis when a chronically ill patient Metabolic acidosis can also be caused by ingestion of has an acute exacerbation of her disease or when more than substances that are toxic or in toxic doses. Certain alcohols one active disease process is present. cannot be metabolized by the body and produce metabolic acids as a result of this incomplete metabolism. Respiratory Acidosis Aspirin is another medication that can lead to acidosis. The problem of respiratory acidosis can be further subdivided Aspirin is a medication that many people take to decrease into two categories: either too much carbonic acid production the risk of a heart attack, whereas some people take it as an or too little ventilation. The classic case of too much carbonic analgesic. Aspirin is the active ingredient in many over the acid production is the patient with a fever, pyrexia, whose counter (OTC) medications. In high doses, aspirin, (chemi- body is hypermetabolic. The acute nature of fever causes the cal name: acetylsalicylic acid and abbreviated as ASA) can body’s metabolism to increase, producing additional carbon cause metabolic acidosis. In severe cases of aspirin overdose dioxide and other by-products. aspirin inhibits the respiratory center in the medulla, leading The more traditional cause of respiratory acidosis is to hypoventilation and compounding the metabolic acidosis hypoventilation. Conditions such as strokes, brain trauma, with a respiratory acidosis. and drug intoxication—especially with opiates—can depress Treatment of acidosis from a metabolic cause typically the respiratory drive at the respiratory center in the medulla. involves fi rst ensuring adequate circulation. This may include Spinal cord trauma and diseases that affect the nerves or the administering intravenous fl uids, administering medica- muscles can cause either the respiratory muscles or the nerves tions to increase the patient’s blood pressure, administering controlling the respiratory muscles to provide inadequate antibiotics to treat infection, or performing chest compres- ventilation, which in turn causes hypoventilation. Illness and sions during cardiac arrest. These supportive measures help injury to the lungs themselves can result in hypoventilation. the body resolve the acidosis naturally. Sodium bicarbonate Any condition, either traumatic or medical, that impairs gas is sometimes administered intravenously in an attempt to exchange reduces the lungs’ ability to exchange oxygen and correct a severe metabolic acidosis by providing additional carbon dioxide, producing a respiratory acidosis. bicarbonate to buffer the acid. Treatments for the patient experiencing respiratory aci- As acidotic patients tend to hyperventilate as a way of dosis focus on ensuring the patient has adequate oxygenation compensating for the metabolic acidosis, if the Paramedic 498 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. needs to secure the airway, the Paramedic must remember to (e.g., when a person jumps up from a resting position and either ventilate the patient at a higher rate or set the respi- runs a quarter mile sprint), the respiratory rate increases ratory rate on the ventilator to a higher-than-normal rate in rapidly in response to the increased metabolic CO produc- 2 order to maintain an adequate ventilatory rate for that com- tion. At the end of the race, when the metabolic production pensation. If too low of a respiratory rate is provided, and the of CO decreases, the respiratory rate will decrease to the 2 underlying metabolic process is not corrected, the patient will baseline rate over the course of several minutes. In some continue to become more acidotic until the patient goes into conditions, however, there is a mismatch between the respi- a cardiac arrest. Cardiac arrest in these cases often does not ratory rate and CO production, with the patient breathing at 2 respond to treatment because of the severe acidosis. a faster rate than required to handle the production of CO . 2 This increased minute ventilation lowers the CO level, pro- 2 Alkalosis ducing the alkalosis. When a patient has a condition that The blood becomes alkalotic if the pH rises above 7.45. As causes metabolic acidosis, this mechanism compensates for with acidosis, this can be due to either a respiratory or meta- the acidosis and helps move the pH back toward the normal bolic cause. Alkalosis from a metabolic cause occurs more range. However, when the patient does not have an existing often than from respiratory etiologies. metabolic acidosis, this increased ventilation stimulus pro- duces the respiratory alkalosis. Metabolic Alkalosis There are several causes for the increased stimulation. Normally, if hypoxemia occurs in the central circulation, Metabolic alkalosis is caused by an increase in the produc- receptors in the aorta and carotid arteries will signal the tion of bicarbonate in the blood. This can be due to a meta- respiratory center to increase the respiratory rate in order to bolic process in the body and can also be due to increased compensate for the decreased oxygenation. However, in some kidney reabsorption of bicarbonate from the urine. Common situations, the central circulation is not hypoxemic. However, causes of metabolic alkalosis include severe volume deple- the tissues are hypoxic, and cause an increase in respiratory tion and acid loss, as occurs in dehydration from vomiting, rate. Any condition that decreases the off-loading of oxy- and electrolyte disturbances (e.g., low potassium), which gen at the tissue level (e.g., shock or anemia) can cause an triggers reabsorption of bicarbonate by the kidneys. Certain increase in the respiratory rate. endocrine disorders can also produce a metabolic alkalosis A second abnormal stimulus for increased ventilation by decreasing the serum potassium level. The use of some can occur with abnormal stimulation of the stretch |
receptors diuretics, specifi cally those that spill potassium into the urine located in the alveoli and smaller air passages in the lungs. (e.g., potassium wasting diuretics), can cause a metabolic Normally, the stretch receptors help signal the start and stop alkalosis because they cause an increase in reabsorption of of ventilation. However, in the case of irritation of the alve- bicarbonate. oli from pneumonia, pleural effusion (abnormal liquid in- Treatment of metabolic alkalosis depends upon the between the pleural layers), or congestion in the pulmonary cause. In the case of volume depletion (e.g., from vomit- capillaries, the stretch receptors can trigger increased ventila- ing, diarrhea, or overdiuresis), administering normal saline tion, producing a respiratory alkalosis. will help correct the volume loss. It is important to moni- The respiratory center can be directly stimulated by a tor the patient’s oxygenation, as the body’s primary means of variety of conditions and produce increased ventilation. Cer- compensating for a metabolic alkalosis is to hypoventilate, tain toxins, either ingested or produced by other conditions producing a mild respiratory acidosis to compensate for the (e.g., liver failure or renal failure) can trigger increased venti- metabolic alkalosis. In patients with normal respiratory func- lation. Fever or the toxins in sepsis can also increase ventila- tion, the effect of the hypoventilation is minimal. However, tion and produce a respiratory alkalosis. Certain hormones in patients who have a signifi cant respiratory condition (e.g., can also stimulate increased ventilation. This occurs as a chronic obstructive pulmonary disease (COPD)), hypoventi- normal part of pregnancy to increase respiratory rate late in lation may not be tolerated well and the patient may become pregnancy to compensate for diffi culty in fully expanding the hypoxic. Supplemental oxygen may be required to treat the lungs due to the growing fetus. Changes in blood chemistry hypoxia. In patients who are paralyzed and on a ventilator, that occur when at altitude also produce a mild hyperventila- the respiratory rate can be decreased to help treat the meta- tion to compensate for the lower partial pressure of oxygen bolic alkalosis. at high altitude. Respiratory Alkalosis Finally, psychologically induced hyperventilation can occur as a response to fear, anxiety, pain, or any number of Respiratory alkalosis occurs when ventilation is greater than emotional stressors. This increased respiratory rate can be the body’s CO production. As previously discussed, the CO 2 2 either involuntary or voluntary and often responds to calming generated by the body is primarily removed by the respi- and reassurance. With severe hyperventilation, the decrease ratory system. Changes in the respiratory rate occur very in blood CO causes vasoconstriction of cerebral blood ves- 2 rapidly in response to an increase or decrease in the circu- sels, reducing blood fl ow. In some cases, this can cause light- lating CO level. When the metabolic rate increases quickly 2 headedness or even syncope. Ventilation 499 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. in Chapter 16 and during the airway management chapters Street Smart (Chapters 22 and 23). In this section, we will discuss some of the objective measures of oxygenation and ventilation, including pulse oximetry, capnography, co-oximetry, and It is very easy to blame hyperventilation on a arterial blood gas sampling. psychological cause. Be aware that many other conditions can produce hyperventilation, including Pulse Oximetry hypoxia, shock, and sepsis. Search for these Pulse oximetry is a non-invasive measure of the percentage of causes during your patient assessment and treat hemoglobin sites in the red blood cells that are bound to oxy- gen, or oxyhemoglobin. This percentage of oxyhemoglobin is them appropriately. Do not allow the patient to called oxygen saturation and is abbreviated as SpO . A normal 2 breathe into a paper bag or an oxygen mask that SpO is between 95% and 100%. An SpO reading between 2 2 is disconnected from supplemental oxygen! This 90% and 95% indicates mild hypoxemia, and a reading between 85% and 90% indicates moderate hypoxemia. A reading below rebreathing will produce an abnormal increase in CO2. 85% indicates severe hypoxemia requiring intervention by the For the patient that is hyperventilating in response to Paramedic. There are two ways to report oxygen saturation: a pathologic cause, this increase in CO2 may produce One is displaying a quantitative measure of the oxygen satu- unconsciousness, profound metabolic derangements, ration and the other is displaying the oxygen saturation as a waveform over time. For oximeters that only display a numeri- and cardiac arrest. cal value, there is an indication of signal strength that provides the Paramedic with an indication of the strength of the blood Treatment of respiratory alkalosis depends on the cause. fl ow across the sensor. For oximeters that provide a waveform If the patient is hypoxic or there is a reason for tissue hypoxia display in addition to the numerical value, the shape of the (e.g., shock), then providing supplemental oxygen or treat- waveform provides the Paramedic with a visual indication of ment of shock may improve the alkalosis. If psychogenic the strength of the blood fl ow across the sensor (Figure 25-7). causes are present, attempt to calm the patient, provide reas- Technology surance, and appropriately treat pain and anxiety. Consider other respiratory or central causes when developing a para- Measurement of the SpO involves beaming a light wave 2 medical diagnosis, ensure the patient’s ABCs, and provide across the patient’s capillary bed and detecting the wave- supportive care. length on the opposite side of the capillary bed. The light Mixed Disorders The four acid–base disturbances should not be thought of as isolated entities. In reality, the body is complex and will respond both acutely and chronically to compensate for these dysfunctions. Some disease processes, or combination of disease processes, may cause a mixed acid–base disorder, where a primary disorder (e.g., respiratory acidosis) is par- tially compensated by the body by another disorder (e.g., a metabolic alkalosis). In some cases, the acidosis and alkalo- sis can have both a respiratory and metabolic cause (e.g., a respiratory and metabolic acidosis that can occur with some conditions). These disorders can be challenging to sort out. When in doubt, fall back to the ABCs and ensure the patient has a patent airway, is well ventilated and oxygenated, and is not in shock. This can be easily summarized as supporting the ABCs. This initial attempt at resuscitation and stabilization can go a long way in improving the patient’s condition. Assessment of Oxygenation and Ventilation The Paramedic has several tools at her disposal to help assess Figure 25-7 Pulse oximeters may display a oxygenation and ventilation in the critical patient. Clinical numerical indication of SpO2 or waveform display assessment of oxygenation and ventilation was discussed of SpO2. 500 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. wave is combined red and infrared frequencies. As the wave SpO reading (Figure 25-8). The waveform amplitude fl uc- 2 passes through the capillary bed, the light is absorbed by the tuates normally, corresponding to the fl ow of blood through hemoglobin differently depending on if it is in the oxyhemo- the capillary bed. If the Paramedic encounters a poor quality globin form or the deoxyhemoglobin form. The oxyhemo- waveform (Figure 25-9), the Paramedic will need to place the globin form absorbs more infrared light than red (therefore sensor on a different site. explaining the bright red color of oxygenated blood) and deoxyhemoglobin absorbs more red light than infrared. The Clinical Application wavelengths at the light source are known and compared to There are several factors that affect the accuracy of the wave- the wavelengths detected at the sensor. The ratio between the form or the perfusion index. In low blood fl ow states (e.g., wavelengths transmitted and received is compared with a hypotension from shock or cardiac arrest), there may not be database of known values and is used to calculate the SpO . a suffi cient movement of blood through the capillary bed to 2 These known values are only available in the range of 70% to provide an accurate reading. Decreased capillary blood fl ow 100% saturation as this information was derived from actual can also occur when the sensor site is cold and the blood ves- patients. sels are constricted. Vasoconstriction is a normal response The most common source used to measure SpO is the to cold, shunting warm blood toward the core to maintain 2 tip of a fi nger. Light travels easily through the fi ngertip and a normal body temperature; however, it can be problematic the capillary bed is relatively superfi cial to the skin surface. when attempting to obtain an accurate SpO reading. Vibra- 2 Alternatively, the earlobe can also be used for a similar rea- tion from shivering and motion artifact during transport may son. Two other sites include tip of the toes, useful in children, also affect the quality of the waveform, although this is not and the skin on the forehead, useful in hypothermic patients. as much of an issue with the later models of pulse oximeters. The strength of the signal detected by the pulse oximeter Nail polish may affect the ability of the light to pass through is reported as the perfusion index on oximeters that do not the fi ngertip and may need to be removed if a poor waveform display a waveform. The perfusion index is measured from or inadequate perfusion index is noted. Finally, the pulse oxi- 0.02% to 20%, with the larger number indicating a stronger meter is inaccurate below an SpO of 70% because the refer- 2 signal. The higher the perfusion index, the more accurate the ence database in the machine does not contain information reading. Therefore, when using device pulse oximeter, the below 70%. Paramedic can use the perfusion index indicator to know if A normal SpO reading doesn’t mean the patient does not 2 the pulse SpO reading displayed is an accurate reading. In require supplemental oxygen. While anemia, or decreased 2 some cases, the Paramedic will need to try several different hemoglobin, does not affect the SpO , total blood oxy- 2 sites before obtaining an accurate SpO reading. The pulse gen content—and therefore the delivery of oxygen to the 2 rate is calculated from the time between peaks of the fl uctuat- tissues—is decreased. Total blood oxygen content depends ing pulse oximetry wave. on the amount of hemoglobin in the blood and the amount For devices that display a waveform, the shape of the of oxygen diffused into the blood. The total amount of dis- waveform can be used to determine the accuracy of the solved oxygen in the blood can be increased by administering Figure 25-8 Normal pulse oximetry waveform. Ventilation 501 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Figure 25-9 Poor waveform that affects the accuracy of the SpO2 reading. supplemental oxygen to patients suspected of anemia from are available that can detect the presence of these two condi- acute blood loss, and may help prevent tissue hypoxia from tions. This will be discussed later in this chapter. inadequate oxygen transport. Patients in respiratory distress Pulse oximetry also does not provide an indication or or shock often increase their respiratory rate and pulse rate |
in measure of the patient’s ventilatory status. This is especially order to move more oxygen into the blood and circulate more true when the patient is on high-fl ow supplemental oxygen. oxygen to the tissues in response to a lack of oxygen at the The supplemental oxygen can replace the other gasses in the tissues. In many cases, a patient in respiratory distress will lungs, increasing the oxygen gradient between the alveoli be able to improve his SpO by increasing his respiratory rate and the pulmonary capillary blood. This encourages trans- 2 and compensating for his hypoxemia. The use of supplemen- port of oxygen into the blood, even when there is insuffi cient tal oxygen should not be based on SpO alone, but also on airfl ow in and out of the lungs. That airfl ow in and out of 2 other clinical assessment of respiratory distress as discussed the lungs (ventilation) is required to remove carbon dioxide in Chapter 16. from the system. With inadequate airfl ow, the carbon dioxide Certain conditions will also affect the SpO reading. Car- levels increase in the alveoli, decreasing the gradient from 2 bon monoxide also attaches to hemoglobin; because, it has the blood to the alveoli, reducing carbon dioxide transport a signifi cantly higher affi nity than oxygen. This means that and therefore increasing blood carbon dioxide levels. Pulse carbon monoxide is 200 times more likely to attach to the oximetry alone would not detect this hypoventilation. This hemoglobin molecule than oxygen, creating carboxyhemo- is well illustrated in a case report from 1993, approximately globin. Though the hemoglobin is bound to carbon monoxide 5 to 10 years after pulse oximetry’s introduction into regular rather than oxygen, the wavelengths of light used in fi rst gen- clinical use.3 In this case report, an elderly woman was moni- eration pulse oximeters are not capable of differentiating the tored after a surgical procedure with blood pressure, ECG, two hemoglobins. A patient who has had carbon monoxide and pulse oximetry on supplemental oxygen after her proce- poisoning may demonstrate a normal SpO . Other forms of dure. The patient became less and less responsive. Finally, the 2 hemoglobin (more specifi cally, one form called methemoglo- nurses could not wake the patient up. The patient was seen by bin) will also provide a false SpO reading. Methemoglobin is the anesthesiologist, was noted to be ventilating very poorly, 2 a form of hemoglobin that is chemically different from hemo- and was intubated and placed in the ICU until she woke up. globin and cannot carry oxygen. This is often the form hemo- The pCO on her blood gas was 280 mmHg, with a normal 2 globin takes as it reaches the end of its useful life. A small pCO at 40 mmHg. Most patients who acutely develop a 2 amount of methemoglobin is present in the blood at all times. pCO over 80 or 90 mmHg become minimally responsive or 2 However, the level can be markedly increased in some condi- unresponsive. The patient’s SpO never fell below 96%. The 2 tions, decreasing oxygen transport. Fortunately, co-oximeters take-home message from this case is while pulse oximetry is 502 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. an excellent tool to help assess a patient’s oxygenation and endotracheal confi rmation then utilize continuous waveform ability to oxygenate a patient, it cannot detect hypercapnea, capnography or capnometers. or a rise in CO , from inadequate ventilation. This is where Quantitative capnometers provide a numerical value 2 capnography can help. for the EtCO , reporting the CO measurement at the end of 2 2 exhalation. In contrast, waveform capnography records the Capnography values of exhaled carbon dioxide throughout the inspiration– expiration cycle and graphs that value over time, producing a Capnography, the measurement of the amount of carbon diox- waveform that can be clinically useful to interpret. ide exhaled from the lungs, is a newer technology that can help guide the Paramedic with treatment in several clinical situa- tions. Several different methods of capnography are available Technology to measure exhaled carbon dioxide. The measurement often As previously described, the colorimetric capnometers uti- cited is the end-tidal carbon dioxide, which is the amount of lize a paper impregnated with a chemical that changes color carbon dioxide in the air at the end of exhalation. End-tidal depending upon the amount of carbon dioxide in the exhaled carbon dioxide is abbreviated as EtCO . The three methods of 2 air. For quantitative capnometry and waveform capnogra- measuring EtCO include colorimetric capnometry, quantita- 2 phy, the amount of carbon dioxide in exhaled air is found tive (numerical) capnometry, and waveform capnography. by shining a beam of infrared light through a sample of the Colorimetric capnometry is a familiar form of EtCO for 2 exhaled breath. The intensity of the light is then compared to many Paramedics. This device consists of a piece of litmus a measurement taken from an air sample that does not contain paper within the sensor’s body. This paper is impregnated with carbon dioxide. The certain wavelengths of infrared light are a chemical that changes color when exposed to exhaled car- absorbed by the presence of carbon dioxide compared to the bon dioxide (Figure 25-10). This device is placed in-line with air that does not contain carbon dioxide. This is converted the endotracheal tube immediately after endotracheal intuba- into a numerical measure of the carbon dioxide. tion to help confi rm that the the endotracheal tube is in the tra- Exhaled air for use in capnography or capnometer is chea. If the endotracheal tube is in the trachea the capnometer sampled in one of two different methods. Mainstream cap- should change color from purple up to yellow depending on nography involves placing the sensor in-line with the exhaled the amount of carbon dioxide in the exhaled air. One exception air stream and can only be used in intubated patients (Figure is when a patient has been in cardiac arrest for a prolonged 25-11a). The sensor is placed between the endotracheal tube period of time. In this situation, very little CO is transported 2 and the ventilation device (e.g., bag-valve mask assembly). to the lungs because of circulatory collapse, therefore there is The second method is called sidestream sampling. Side- little in the lungs and a low level in exhaled gas. stream capnography involves taking a sample of the exhaled The colorimetric capnometer is a qualitative device, air by aspirating a small amount of it from the exhaled air meaning it gives gross estimations of the presence or absence stream, either from the endotracheal tube or through the use of carbon dioxide and not specifi c levels of carbon dioxide. of a modifi ed nasal cannula (Figure 25-11b). Sidestream This, and other limitations, give colorimetric capnometry technology allows capnography to be used in patients who limited utility in the prehospital setting. Some Paramedics are not intubated. only use colorimetric capnometer as an initial method of One disadvantage to sidestream capnography/ capnometer is that there is some loss of carbon dioxide from the air sam- ple that occurs between the patient and the monitor. This is overcome in many capnography/capnometer devices by cali- brating the EtCO2 monitor whenever the monitor switches measurement methods from endotracheal measurements to nasal cannula. A second disadvantage of nasal cannula sidestream c apnography/capnometer is if the patient is receiving high- fl ow oxygen (e.g., using a nonrebreather or CPAP mask) at the time of sampling, the result will be artifi cially low because the high-fl ow oxygen blowing past the sampling port will wash out much of the carbon dioxide in the exhaled air. The sampled exhaled air is taken to a chamber where a beam of infrared light is directed through the sample. The carbon dioxide present in the air absorbs some of the infra- Figure 25-10 The EasyCap® colorimetric red light, changing the wavelength of the light that contin- capnometer. The color changes from purple when ues through to the sensor. This change in wavelength varies exposed to > 4 mmHg CO2, to tan, and then to with the amount of carbon dioxide present in the sample. The yellow when exposed to > 15 mmHg CO2. sample taken from exhaled air is compared with infrared light Ventilation 503 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. (a) (b) Figure 25-11 Mainstream versus sidestream sampling. (a) In mainstream capnography, the sensor is located between the endotracheal tube and the bag-mask assembly. (b) A modifi ed nasal cannula is used to sample carbon dioxide from exhaled air. beamed through a sample with a known concentration of car- Measured bon dioxide. This comparison determines the level of exhaled EtCO2 carbon dioxide in the patient’s breath. In the absence of respi- III ratory disease, this measure of exhaled carbon dioxide should be within 5 mmHg of the partial pressure of carbon dioxide β (PaCO ) of the patient’s arterial blood. α Alveolar 2 0 plateau Capnography: Waveform Interpretation II Unlike capnometers which either provide a visible color change or a numeric readout, a capnography provides a graph I Expiratory Inspiratory of the EtCO measurement as it changes during inspiration 2 upstroke downstroke and expiration (Figure 25-12), The capnography waveform has several components, each representing a phase. Respiratory Phase I is the respiratory baseline and occurs at the time baseline between inhalation and exhalation. It should be at zero, as it (should be 0 mmHg) represents the carbon dioxide in free air, that is found in the anatomical dead space in the lungs.4 The next part of the wave- Figure 25-12 Anatomy of a typical end-tidal form, Phase II, is also called the expiratory upstroke and rep- capnography waveform. resents the beginning of exhalation of air from the lungs that contains carbon dioxide. The third part of the waveform, known as Phase III or the alveolar plateau, represents exhalation of The fi rst angle on the waveform, the alpha angle, is the angle alveolar air during exhalation. The peak of this plateau at the between Phase I and II and indicates the correlation between end of exhalation is the EtCO measurement displayed on the ventilation and perfusion in the lung (i.e., the movement of air 2 monitor. The fi nal portion of the waveform is the inspiratory in and out versus the fl ow of blood through the lungs). The sec- downstroke or Phase 0, and represents the patient’s inspiration. ond angle, the beta angle, the angle between Phase III and 0, is During the inspiratory downstroke, the EtCO falls rapidly to usually close to a 90-degree angle. However, it will increase if 2 zero, as the inspired air should contain little carbon dioxide. the patient is rebreathing exhaled carbon dioxide, as can occur 504 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. if the oxygen fl ow rate on a nonrebreather is inadequate and the not only represents a signifi cant means of improving patient reservoir bag does not refi ll between breaths. safety but also is a risk management tool used to protect Para- medics from allegations of malpractice.. Clinical Application Changes in the shape of the |
capnography waveform can also provide valuable information to the Paramedic regard- The earliest clinical use of capnometry in the prehospital setting ing the patient’s respiratory disease, circulatory status, and was using colorimetric capnometer to confi rm proper place- equipment failure. For example, with severe bronchospasm, ment of the endotracheal tube after orotracheal or nasotracheal the patient will have diffi culty exhaling. This is refl ected in a intubation. After intubation, and auscultation of breath and epi- sloping of the alveolar plateau (often referred to as a “shark gastric sounds, the colorimetric capnometer is placed between fi n shape”) and a longer alveolar plateau (Figure 25-14) rep- the bag-valve mask assembly and the endotracheal tube and resenting the prolonged expiration that occurs in patients with the bag is squeezed several times. If the endotracheal tube is bronchospasm. As the patient is treated with medications that located within the trachea, then carbon dioxide should be pres- reduce the bronchospasm, the waveform should return to a ent in the exhaled air. If the endotracheal tube is located in the normal or near normal shape. esophagus, there should be no carbon dioxide in the exhaled For intubated and paralyzed patients, waveform capnog- air. If the endotracheal tube is located in the trachea, the cap- raphy can indicate when the paralytic medication is wearing nometer should turn from a purple color during inhalation to a off. As the paralytic medication wears off, the patient will start yellow color during patient exhalation. attempting to breathe. The Paramedic will fi rst notice this by The Paramedic should provide at least six ventilations observing a dip in the alveolar plateau as the patient attempts before relying on the colorimetric capnometer’s color change to take a shallow breath; an increasing carbon dioxide level to indicate proper position. In patients who have ingested car- stimulates the patient to breath (Figure 25-15). This will often bonated beverages, such as beer, just prior to intubation, it is precede muscular movement and provide an early indication of possible for the carbon dioxide in the stomach from the bev- erage to provide a false indication of the presence of carbon dioxide.5 While this is clinically an uncommon event, the Para- medic should be aware of this potential pitfall. Regardless of whether colorimetric capnometry or waveform capnography are used, the level of carbon dioxide present in the stomach in that situation will rapidly decrease to zero during ventilation, thus confi rming the endotracheal tube is in the esophagus. 0 Continuous waveform capnography can provide the Para- medic with an assurance that the properly placed endotracheal Figure 25-13 A sudden loss of the capnography tube remains in the trachea during transport. The prehospital waveform often signals dislodgement of the environment is full of situations wherein patient care can eas- endotracheal tube from the trachea. ily dislodge the properly placed endotracheal tube, from log- rolling the patient onto a backboard at the scene to moving the patient from the EMS stretcher to the emergency depart- ment gurney. When the patient is monitored with continuous waveform capnography, dislodgement of the endotracheal tube is immediately indicated by a loss of capnography waveform (Figure 25-13). As discussed in Chapter 24, a well-o xygenated patient without signifi cant respiratory disease can endure 0 nearly eight minutes of apnea time before her SpO falls below 2 90%. With the loss of exhalation waveform from continuous Figure 25-14 Characteristic shape of the waveform for a patient with bronchospasm. waveform capnography, the Paramedic immediately recognizes endotracheal tube dislodgement. This was well demonstrated clinically in a study that examined the rate of misplaced endo- tracheal tubes in intubated patients transported to their trauma center by various EMS services.6 Some EMS services had implemented endotracheal tube placement monitoring with continuous waveform capnography while others had not. In the group of patients that were monitored with continuous wave- 0 form capnography, zero patients arrived with an endotracheal tube in the esophagus compared with 23% of the patients in the Figure 25-15 The “curare cleft” in the alveolar group that was not monitored using continuous waveform cap- plateau is the fi rst sign that the paralytic nography. Continuous monitoring with waveform capnography medication is wearing off. Ventilation 505 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. the need to administer additional paralytic medication before of carbon dioxide in the blood or in the lungs, but because the patient begins to resist positive pressure ventilation by of the lack of carbon dioxide diffusion secondary to lack of coughing against inhalation, called “bucking” the ventilator. circulation due to cardiac arrest. Capnography or capnometry Waveform capnography can also alert the Paramedic alone may not be suffi cient to confi rm proper placement of to technical or equipment problems. From failure of valves the endotracheal tube in a patient who has been in cardiac in the bag-valve-mask assembly to kinking of the endotra- arrest for a prolonged period of time due to the lack of circu- cheal tube, equipment failure can reduce airfl ow both in lation. Once adequate chest compressions begin, the EtCO 2 inspiration and expiration and cause changes in the wave- rises as there is generally enough circulation to produce a form (Figure 25-16). This pattern is also seen in partial noticeable level of exhaled carbon dioxide. If the EtCO level 2 obstruction of the endotracheal tube which can occur with remains below 10 mmHg after 20 minutes of the usual resus- excessive mucus or other material in the airway. A raising citation efforts, there is a 0% chance of survival.7,8 baseline suggests that the patient may need deep endotracheal suctioning. A gradual rise in the Phase I baseline often indicates con- tamination of the sensor when using mainstream capnography (Figure 25-17). This can occur from either foreign material or a buildup of condensation on the sensor that changes the infrared light transmission across the exhaled air. Disconnect- ing and cleaning the sensor generally resolves this problem. 0 Capnography can also detect hyper- and hypoventila- tion, both in spontaneously breathing patients and ventilated Figure 25-16 Abnormalities in both the Phase III patients. A gradual decrease in the height of the waveform and 0 parts of the waveform may indicate kinking indicates hyperventilation (Figure 25-18a). This occurs as the or partial obstruction of the endotracheal tube. increased alveolar minute volume removes additional carbon dioxide, decreasing the amount of carbon dioxide in subse- quent breaths. This can be used during bag-valve ventilation to maintain a constant rate and depth to prevent hyperventi- lating the patient. Conversely, a gradual increase in the height of the waveform with a constant baseline indicates hypoventi- lation (Figure 25-18b) and may indicate to the Paramedic that he needs to intervene to improve the patient’s ventilation. 0 Another use for capnography is to predict the likelihood Figure 25-17 The gradual increase in of survival in cardiac arrest. The initial EtCO readings in a 2 respiratory baseline often indicates a problem patient in cardiac arrest are near zero, not because of the lack with the mainstream capnography sensor. ETCO2 mmHg 60 60 40 40 20 20 NORMAL TIMEBASE (a) ETCO2 mmHg 60 60 40 40 20 20 NORMAL TIMEBASE (b) Figure 25-18 Gradual changes in the waveform height while maintaining a zero baseline can indicate (a) hyperventilation or (b) hypoventilation. 506 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Upon return of spontaneous circulation, the EtCO level will when the patient has developed methemoglobinemia. Carbon 2 sharply rise, often before the pulse is palpable.9,10 Capnography monoxide differs from carbon dioxide in that carbon monox- has also been suggested to help guide the effectiveness of chest ide only has one oxygen atom in the molecule. Carbon mon- compressions in cardiac arrest. However, it is not known whether oxide attaches to the same site as oxygen on the hemoglobin this translates into improved survival from cardiac arrest.11 molecule, only it attaches 200 times stronger than oxygen. End-tidal carbon dioxide level will change with changes in This displaces oxygen and decreases the overall ability to the patient’s hemodynamics and may be a useful tool in guid- transport oxygen to the tissues. A pulse oximeter, however, ing trauma resuscitation.12 It is important to note that while will still see the hemoglobin as saturated, and report a nor- specifi c EtCO levels do not correspond to specifi c levels of mal SpO . Methemoglobinemia occurs when the hemoglobin 2 2 shock, sudden changes or trends can assist the Paramedic in molecule undergoes a change in its form that removes one guiding treatment. As previously discussed, EtCO will change electron from the atom. This form of hemoglobin cannot carry 2 with changes in blood fl ow due to decreased perfusion and car- oxygen. The pulse oximeter will often read falsely low SpO 2 bon dioxide transport to the lungs. The issue with using EtCO in patients with a low level of methemoglobinemia and falsely 2 in guiding trauma is the reading is not only dependent on cir- high SpO in higher percentages of methemoglobinemia.14 2 culatory fl ow, but also dependent on carbon dioxide transport Carboxyhemoglobin (COHgb) and methemoglobin from the blood into the alveoli and constant alveolar minute (MetHgb) levels are often obtained in the hospital using a sam- volume, which varies based on the tidal volume and ventilation ple of either arterial or venous blood and requiring a s pecial rate. Changes in EtCO levels should refl ect changes in circula- co-o ximeter. More recently, a non-invasive co-oximeter was 2 tion if the alveolar minute volume is held constant. For trauma developed to non-invasively measure SpO , COHb, and MetHB. 2 patients who have sustained a chest or respiratory system injury signifi cant enough to impede gas exchange, changes in Technology the EtCO reading may refl ect worsening pulmonary condition 2 The Masimo® RAD-57 was introduced as the fi rst handheld rather than circulatory status. Sublingual capnometry using non-invasive co-oximeter. Eight different wavelengths of light a non-invasive probe that sits underneath the tongue showed are transmitted through the capillary bed.15 Changes in the some promise in more accurately detecting tissue perfusion wavelength of these eight different beams are used to compute without relying on maintaining a constant ventilation minute a percentage of SpO , COHgb, and MetHgb in the blood in the 2 volume. However, the manufacturer recalled the probes and capillary bed. This particular co-oximeter also reports the per- the device is not currently available.13 fusion index, which is helpful in determining signal strength, Finally, capnography can be used during procedural seda- and ultimately the accuracy of the patient’s SpO . 2 tion as a way of monitoring the patient’s respiratory rate and ventilation status during the sedation. The most common use Clinical Applications for procedural sedation in the prehospital setting is for cardio- The Masimo® RAD-57 may show some promise in the pre- version, which involves applying an electric shock across the hospital environment in helping to triage a large number of chest to stop a fast heart rhythm, or when electrically pacing patients who may have been exposed to carbon monoxide, the patient, which involves periodically applying electricity thus minimizing transports.16 The Paramedic’s ability to across the chest to produce a mechanical cardiac contraction. non- invasively monitor COHgb levels in fi refi ghters during Both of these procedures are painful. Medications that are fi reground operations may detect elevated COHgb in inte- used for sedation also have the side effect of depressing res- rior fi refi ghters during both fi re suppression and overhaul piration and decreasing ventilation. As discussed in |
the case operations.17,18 This may impact fi refi ghter health by keeping study described in the pulse oximetry section, it is possible to fi refi ghters out of the rotation while treating mildly elevated have a well-oxygenated and poorly ventilated patient who can levels of COHgb, as it has been established that carbon mon- progress to respiratory failure. Capnography adds a level of oxide exposure can cause long-term cardiac effects.19 safety by providing a graphical representation of the patient’s respiratory rate, depth of respiration, and EtCO . As the patient 2 Arterial Blood Gas becomes more sedated, and ventilation deteriorates, the EtCO 2 will rise, providing an alert to the Paramedic that she may need The gold standard measurement of oxygenation and venti- to intervene by either assisting ventilations or reducing the lation in medicine before the advent of pulse oximetry and level of sedation before the patient suffers respiratory failure. capnography was the arterial blood gas (ABG). Even today, in the emergency department and critical care setting, the ABG provides a lot of useful information about not only the Co-oximetry patient’s oxygenation and ventilation, but also data used to As discussed under the section on pulse oximetry, one of the assess the patient for acid–base disorders. While the ABG is pitfalls of pulse oximetry is that other forms of hemoglobin the most accurate measure and provides a signifi cant amount can change the wavelength of the light beam in such a way of information, the process to obtain the ABG can be a pain- that it mimics oxyhemoglobin. Two situations where this can ful procedure for most patients. While ABG sampling is often occur are when a patient has carbon monoxide poisoning and not an EMS procedure, Paramedics working in a critical care Ventilation 507 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. transport environment will be exposed to blood gas analysis Table 25-2 Components of the Arterial and may need to use this information to guide therapy dur- Blood Gas ing transport. For Paramedics working in the traditional street EMS environment, conceptual knowledge of ABG analysis Component What Is Measured Normal Range will help them understand the underlying pathophysiology pH Amount of hydrogen atoms 7.35–7.45 present in their patient. in the blood sample Below 7.35 is academia What Is Measured? and above 7.45 is alkalemia The ABG sample is taken from a superfi cial artery and is rap- pCO2 Partial pressure of carbon dioxide 35–45 mmHg idly analyzed using a blood gas analyzer. The most common dissolved in the blood sample location for sampling is the radial artery at the wrist; how- Less than 35 is hypocapnea ever, the brachial artery near the elbow or the femoral artery and greater than 45 is in the groin can also be used to obtain a sample. Critical hypercapnea patients who are undergoing transport may have an arterial PO2 Partial pressure of oxygen 70–100 mmHg line (Figure 25-19) placed by the sending hospital to con- dissolved in the blood sample tinuously monitor the patient’s blood pressure and serve as Less than 70 is hypoxia and a means of painlessly acquiring multiple ABG samples in an greater than 100 is hyperoxia unstable patient. HCO - 3 Amount of bicarbonate ions in 22–30 mmol/L The ABG sample is measured for the pH, pCO , PO , the blood sample 2 2 bicarbonate (HCO –), and oxygen saturation. The ABG Less than 22 is hypocarbia 3 analyzer may also include serum electrolytes, lactate, glu- and greater than 30 is cose, hemoglobin, and base excess or defi cit (Table 25-2). hypercarbia The values from the ABG sample can be used to determine if the patient has an acid–base disorder and, if a disorder is <7.35 >7.45 pH present, identify the acid–base disorder. HCO3–<24 pCO2>40 HCO – 3 <24 pCO2<40 Interpretation of Arterial Blood Gasses Acidosis Alkalosis This section uses a simple method to identify the primary acid–base disorder (Figure 25-20). The primary acid–base Metabolic Respiratory Metabolic Respiratory disorder is the disorder that is the primary cause of the aca- Acidosis Acidosis Alkalosis Alkalosis demia or alkalemia. As previously discussed, the body will work to compensate for the primary disorder in an attempt to Figure 25-20 Algorithm for interpreting arterial blood gas.20 bring the arterial blood pH back toward normal. In reviewing the algorithm, notice that if the pH and bicarbonate move in the same direction (e.g., both increase or both decrease), then the primary disorder is a metabolic disorder. If the pH and the pCO move in opposite directions (e.g., pH decreases and the 2 pCO increases), then the primary disorder is respiratory. 2 An ABG sample taken from a patient returns with a pH of 7.25, a pCO of 60 mmHg, and an HCO – of 25 mmol/L. 2 3 Starting at the top, the pH is below 7.35, which moves toward the acidosis arm. Looking at the pCO of 60 mmHg, 2 this is greater than 45, indicating a primary respiratory aci- dosis. As previously discussed, this would likely be due to hypoventilation. Mixed disorders have a component of two primary acid– base disorders. In order to detect the presence of a mixed disorder, the Paramedic needs to determine the degree of compensation by the body for the primary disorder. If the degree of compensation is not as expected, this suggests a mixed disorder is present. There are two ways to determine the degree of compen- Figure 25-19 An arterial line painlessly sation. The fi rst is to use formulas to compare the measured allows multiple ABG samples as well as invasive values in the ABG with the expected values (Table 25-3). monitoring of the patient’s blood pressure during With this method, the Paramedic fi rst uses the algorithm in transport. (Photo courtesy of Keith D. Lamb, RRT) Figure 25-20 to determine the primary disorder. Next, the 508 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Table 25-3 Formulas used to Determine if the Paramedic looks in Table 25-3 to determine what formula to Patient Is Compensating for His Primary Disorder21 apply to determine compensation. For example, a Paramedic determines that her patient has a respiratory acidosis. Under Primary Disorder Expected Change respiratory acidosis in Table 25-3, the Paramedic computes Metabolic acidosis pCO2 1.5 [HCO – 3 ] 8 the expected bicarbonate using the formula for acute respira- (range of ± 2) tory acidosis. If the actual bicarbonate on the blood gas is Metabolic alkalosis pCO2 0.7 [HCO – 3 ] 20 different, then the Paramedic computes the expected bicar- (range of ± 5) bonate using the formula for chronic respiratory acidosis. If Respiratory acidosis Acute: HCO – 3 24 ((pCO2 – 40)/10) the expected value still is not close to the measured value, this Chronic: HCO – 3 24 4 ((pCO2 – 40)/10) suggests that a mixed acid–base disorder is present. Respiratory alkalosis Acute: HCO – 3 24 – 2 ((40 – pCO2)/10) A second method of determining the degree of compen- Chronic: HCO – 3 24 – 5 ((40 – pCO2)/10) sation is to use a nomogram (Figure 25-21) after using the (Range of ± 2) algorithm in Figure 25-20 to identify the primary disorder. pCO2 (mm Hg) 110 100 90 80 70 60 50 45 40 60 NORMAL 35 55 50 30 45 40 25 35 p 20 C 30 O2 RESP A IR C A ID TO O R S Y I 25 S 24 15 RESP A I 20 L R K A A T L O O R S Y IS LIC pCO2 AC ID OS ISAB O 10 15 ME T 10 5 NORMAL 0 7.00 7.10 7.20 7.30 7.40 7.50 7.60 7.70 7.80 Acidosis Alkalosis Arterial pH Figure 25-21 Acid–base interpretation nomogram. Ventilation 509 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Plasma (HCO3 ) mEq/L ME A TL AK BA OLO LIS CIS pCO2 (mm Hg) The pH is listed across the bottom of the chart, the HCO – is taken from a peripheral vein instead of an artery. This is 3 listed along the left side, and the curved lines are the values much less painful for the patient and can often be drawn for the pCO . The three values for the pH, HCO –, and pCO from an existing intravenous line. While the PO is dras- 2 3 2 2 are plotted on the chart. Depending on where the intersection tically different between an arterial and venous sample, of those three values falls on the chart, the shaded areas on the pH is approximately 0.04 less than the arterial sample, the nomogram will indicate the type of disorder present. If pCO is within 6 mmHg of the arterial sample, and HCO – is 2 3 the point falls outside the shaded area, this indicates a mixed within 1.5 mmol/L.22 While in some patients this may not disorder is present. adequately refl ect their acid–base status, in many patients this will provide suffi cient information to detect the pres- Venous Blood Gas ence of, and determine, the primary acid–base disorder with A venous blood gas is analyzed in the same way as an arte- less patient discomfort. rial blood gas. The difference between the arterial blood gas and venous blood gas in the venous blood gas sample is 510 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. This chapter has discussed several methods to objectively assess a patient’s oxygenation and ventilation through the use of pulse oximetry, capnography, co-oximetry, and arterial blood gas analysis. The technology and clinical applications of each of these devices were discussed as well as their limitations. The physiology of acid–base disorders and their effects was also discussed. As with all technology, it is important to remember to treat the patient as a whole and not rely solely on one device or technology in determining the paramedical diagnosis and developing an appropriate patient treatment plan. Key Points: • Acids are produced by either respiratory or • The lungs also have the ability to help rid metabolic processes. Although highly necessary for the body of acid. They do this by driving the human survival, a superfl uous amount of acid can acid–bicarbonate formula to the left by exhaling be dangerous to the cells. additional CO2. To do so, the lungs can increase • ventilation, which converts more carbonic acid An acid is a molecule that has a proton without a to CO2 and water. Chemoreceptors monitor paired negatively charged atom. This molecule, cerebrospinal fl uid for an increase in carbonic when exposed to nature, takes the form of a acid, followed by a stimulation of the medulla to positively charged hydrogen (H) ion with one increase respirations. proton. Bases are |
negatively charged molecules, sometimes called hydroxyl molecules (OH), which • The kidneys are the last line of defense when the accept the positively charged molecules of an acid three interlinked buffering systems are unable to to create a more neutral or buffered molecule. suffi ce. The kidneys perform two processes: They • break down excess carbonic acid into bicarbonate, A pH scale was developed in order to describe the which is reabsorbed into the bloodstream, and differing degrees of acidity or alkalinity. This scale excrete excess acids and ammonium in the urine. ranges from 0 to 14. The lower the number, the Kidney compensation is seen in chronically ill more acidotic a molecule, whereas the higher the patients and not acute emergencies due to the fact number, the more alkaline a molecule. A value of 7 that these processes take a long time to activate. is considered neutral. • • Hemoglobin, which is found in the blood, has a An acid that enters the bloodstream encounters high attraction to oxygen. It binds to oxygen and three chemical buffers: bicarbonate (HCO – 3 ), transports it to the body’s tissues, where it is phosphate (PO4) and blood proteins. Bicarbonate released. binds with an acid to eventually create water and CO2 that is eventually exhaled. Phosphate binds • Active cells need oxygen to survive. These cells with acid, which in turn gets excreted into the produce acid, which in turn dilates the capillaries kidneys. This leads to the acidity of urine. Blood and allows more oxygen bound to hemoglobin to proteins, including molecules like hemoglobin, enter. The acid then causes the oxygen to separate bind with acid from the veins and eventually are from its hemoglobin. removed in the lungs or kidneys. Ventilation 511 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. • If the acid in the blood is not released from patient can either produce too much carbonic acid, the body as CO2, oxygen will not attach to its which may cause the metabolism to race, or cause hemoglobin again and be carried out to the a patient to hypoventilate. Hypoventilation is, in capillaries. This will cause a patient to become part, due to certain damage caused by drug abuse, hypoxic. strokes, and brain injuries. • Acidosis, excessive acid in the body, can also hinder • During metabolism, the body makes a variety of the effects of a drug upon the body. If the tissues acids. The production of too many acids can cause are acidotic, it causes a decrease in drug absorption metabolic acidosis (i.e., diabetic ketoacidosis). The into the cell, thus reducing the drug’s effectiveness. body’s organs work together to maintain an acid– • base balance. Any illness or problem with the organs Acidosis can be caused by either respiratory or can deter this process. metabolic acids. In terms of respiratory acidosis, a Review Questions: 1. What two types of acid are products of aerobic 5. Describe the three chemical buffers found in and anaerobic metabolism and what are they the blood and how they help regulate pH. formed from? 6. How do the lungs compensate for an increase 2. By defi nition, what defi nes a substance as an in carbonic acid? acid or a base? What happens when an acid is 7. Using an oxyhemoglobin curve, defi ne the joined with a base? relationship between oxygen saturation and 3. Create a pH scale and label it with the following acid load. terms: weak acid, strong acid, neutral, weak 8. What are two causes of acidosis and how can the base, and strong base. Paramedic recognize them? 4. Explain how carbon dioxide is transported from the cells through the bloodstream and released into the exhaled air. Case Study Questions: Please refer to the Case Study at the beginning of the endotracheal tube in a spontaneously breathing chapter and answer the questions below: patient? 1. How could Mr. Byrnes be having respiratory 3. The Paramedic observes that Mr. Byrnes’ diffi culty and still have a 97% oximetry reading? capnography exhibits a shark fi n pattern. Explain 2. If Mr. Byrnes requires intubation, what this fi nding. methods exist to confi rm placement of the 512 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. References: 1. Merriam-Webster on-line medical dictionary. Available at: http:// 12. Kupnik D, Skok P. Capnometry in the prehospital setting: www2.merriam-webster.com/cgi-bin/mwmednlm?bookMed are we using its potential? Emergency Medicine Journal. ical&varespiration. Accessed December 16, 2007. 2007;24(9):614–617. 2. Ganong WF. Review of Medical Physiology (21st ed.). New York: 13. Creteur J. Gastric and sublingual capnometry. Current Opinion in McGraw-Hill; 2003:670. Critical Care. 2006;12(3):272–277. 3. Davidson JAH, Hosie HE. Limitations of pulse oximetry: 14. Lee DC, Fergusen KL. Methemoglobinemia. Available at: http:// respiratory insuffi ciency—a failure of detection. BMJ. www.emedicine.com/emerg/topic313.htm. Accessed January 18, 1993;307(6900):372–373. 2008. 4. Ward KR, Yealy DM. End-tidal carbon dioxide monitoring 15. Masimo product website. Available at: http://www.masimo.com/ in emergency medicine, part 1: basic principles. Academic Rainbow/rb-overview.htm. Accessed January 18, 2008. Emergency Medicine. 1998;5(6):628–636. 16. Hampson NB, Weaver LK. Noninvasive carbon monoxide 5. Garnett AR, Gervin CA, Gervin AS. Capnographic waveforms in measurement by fi rst responders: a suggested management esophageal intubation: effect of carbonated beverages. Annals of algorithm. JEMS. 2006;31(5):S10–12. Emergency Medicine. 1989;18(4):387–390. 17. Cone DC, MacMillin DS, Van Gelder C, et al. Noninvasive 6. Silvestri S, Ralls GA, Krauss B, et al. The effectiveness of fi reground assessment of carboxyhemoglobin levels in out-of-hospital use of continuous end-tidal carbon dioxide fi refi ghters. Prehospital Emergency Care. 2005;9(1):8–13. monitoring on the rate of unrecognized misplaced intubation 18. Dickinson ET, Mechem CC, Thom SR, et al. Noninvasive within a regional emergency medical services system. Annals of carboxyhemoglobin monitoring of fi refi ghters engaged in fi re Emergency Medicine. 2005;45(5):497–503. suppression and overhaul operations. Prehospital Emergency 7. Levine LR, Wayne MA, Miller CC. End tidal carbon dioxide Care. 2008;12(1):96–97. and outcome of out of hospital cardiac arrest. N Engl J Med. 19. Henry CR, Satran D, Lindgren B, et al. Myocardial injury 1997;337(23):1694–1695. and long term mortality following moderate to severe carbon 8. Grmec S, Klemen P. Does the end-tidal carbon dioxide monoxide poisoning. JAMA. 2006;295(4):398–402. concentration have prognostic value during out of hospital 20. Abelow, B. Understanding Acid Base. Baltimore, Williams & cardiac arrest? European Journal of Emergency Medicine. Wilkins; 1998. 2001;8(4):263–269. 21. Acid Base Physiology. Bedside rules for assessment of 9. Hatlestad D. Capnography as a predictor of the return of compensation. Available at: http://www.anaesthesiamcq.com/ spontaneous circulation. Emergency Medical Services. AcidBaseBook/ab9_3.php. Accessed January 16, 2008. 2004;33(8):75–80. 22. Rang LCF, Murray HE, Wells GA, MacGougan CK. Can 10. Kraus B. Capnography in EMS. Journal of Emergency Medical peripheral venous blood gases replace arterial blood gases in Services. 2003;28(1): 29–41. emergency department patients? CJEM. 2002;4(1): pp. 7–15. 11. Anderson CT, Breen PH. Carbon dioxide kinetics and capnography during critical care. Critical Care. 2000;4(4):207–215. Ventilation 513 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. KEY CONCEPTS: Upon completion of this chapter, it is expected that the reader will understand these following concepts: • The metric system of measurement • Basic drug calculations including weight-dependent drugs and intravenous infusion rates • The six rights of medication administration • Routes for medication administration • Topical anatomy and proper technique for injections Case Study: Mr. Whittendam was a pleasant and proper gentleman with a lengthy cardiac history. He had the new Paramedic enthralled with his recall of previous heart attacks and all of the treatments that he had received in the tiny country hospital many years prior. He said that he had once needed two doses of morphine 1/6gr for severe pain. The senior Paramedic smiled and said he hadn’t thought about grains in a long time. Their current protocols were written in metric measurement. 514 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Principles of Medication Administration 515 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. OVERVIEW The Paramedic has many responsibilities before administering any medication to a patient. These tasks include the six rights of medication administration as well as an ability to carry out calculations using the metric system. This chapter discusses techniques for proper medication administration for the various enteral and parenteral medication routes. Each medication route has pros and cons that will be explored to ensure safety and effectiveness. Medication Administration fl avored with camphor, aniseed, and benzoic acid. Sweeten- ing any tincture makes it into an elixir. The resulting elixir In some instances, it is not so much the medicine adminis- in this case is called paregoric, Greek for something that tered that is crucial but rather the way in which it is given. soothes. Paregoric is very effective against diarrhea, a com- A medicine that is not absorbed into the central circulation, mon malady in developing countries plagued with dysentery where it can be carried to the target organ, is ineffectual. It is and cholera. Paregoric is still listed in the United States Phar- a Paramedic’s responsibility to choose the right drug and the macopoeia as camphorated opium tincture. right dose for the patient, as well as to administer it by the Liquid oral medications commonly face the problem of right route at the right time in order to achieve the optimal tasting badly. The old adage that “a teaspoon of sugar makes therapeutic effect. the medicine go down” shows yet another attempt at making the taking of medicine more pleasant. Medicines mixed with Forms of Medication sugar and water are called syrups. Many cough formulas, some with the opiate codeine, contain sugar water (syrup). The statement “form follows function” holds true for medi- Some medications will not dissolve in a solvent and thus cations. For the untrained layperson, an easy-to-swallow pill remain as fi nely pulverized particles fl oating in the liquid. may appear to be the best carrier for a medication. How- This medication form is called a suspension. It is important ever, for the very old, the very young, and the infi rmed, who that a suspension be shaken before being administered. For- have diffi culty swallowing, a liquid medicine may be better getting to shake the suspension leaves an uneven distribution accepted. of medicine in the solution. Subsequently, the fi rst dose may Numerous forms of medicine have been created over the completely lack the medication if the drug has settled out and centuries. These forms can be grossly categorized into liq- therefore may be impotent, whereas the last dose will be satu- uids, solids, and |
injectable liquids. rated with medication and very potent. Powdered drugs with particles so large that they are vis- Liquid Medication Forms ible when they are mixed, or suspended, in water are called The earliest liquid medications were called spirits. Spirits, magmas. Examples of magmas include milk of magnesia. brewed from various materials, are liquids which have a volatile Oil is also used as an alternative to water as a carrier. Finely oil that evaporates at room temperature and leaves a distinctive pulverized particles placed into oils, such as cod liver oil, are odor in the air. For example, spirit of ammonia has a distinctive called emulsions. The oil in these emulsions also acts as a pungent smell that makes it easily distinguishable from other nutritional supplement; for example, cod liver oil is rich in spirits. An ancient spirit thought to cure a large variety of mala- omega-3 fatty acids as well as vitamins A and D. dies is the “spiritus fermenti.” The modern term for the spiri- Medications meant for the skin (i.e., topical medicine) tus fermenti is whiskey. Alcoholic beverages, including spirits, placed in water are called lotions, whereas those placed in have long been recognized for their medicinal value. either lanolin, an oil from sheep’s wool, or petroleum jelly are Tinctures are medicinal substances that are dissolved called ointments. The choice of oil, water, or chemical base in alcohol. Alcohol has long been used in pharmacy, in part is dependent on whether the medicine is too dry to place on because of its excellent solvent properties and, in part, because the skin or to be absorbed into the skin. of its ready availability. Examples of tinctures include tincture of merthiolate, an early antiseptic, and tincture of benzoin (Friar’s balsam), a combination of balsamic acids whose aromatic vapors Solid Medication Forms are used to relieve nasal congestion and soothe bronchitis. During manufacturing, many medicines can be either Laudanum, a simple tincture of opium, is highly effective extracted chemically or synthesized and then reduced to a dry in relieving a number of maladies including pain and con- powder. The advantage to dry powders is that they are easier stipation. However, its unpleasant aftertaste made it highly to store, they can be stored for a longer period of time without objectionable. To improve its palatability, laudanum was gross deterioration, and they are generally easier to handle. 516 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Use of dried medicine makes sense as most medicines to injected drug levels, without the annoyance of a needle. are reconstituted in the water within the body, and water is a Troches come in more than a dozen fl avors, including blue- universal solvent. When the patient swallows the powder, the berry, butterscotch, caramel, chocolate, peanut butter, and body’s water dissolves the medicine. It is then absorbed into watermelon, and are conveniently packaged in a molded plas- the digestive tract and passes through the portal circulation. tic container which can be carried in a pocket or purse. Some dry medicines still come in a loose powder, usually Other forms of medication that are typically given inter- placed in a waterproof envelope made of wax paper. Goody’s nally for a local effect are suppositories. Suppositories con- headache powder® is an example of a loose powder medi- tain the medicine within a wax carrier which melts at body cation. However, most powdered medications are processed temperature. There are vaginal suppositories, used for yeast into a convenient shape for easy swallowing. A dry medicinal infections, urethral suppositories, and rectal suppositories. powder that is compressed into a pill shape is called a tab- Some rectal suppositories contain chemicals that irritate the let. Tablets are often scored, adding a depression across the bowel lining, triggering defecation and elimination of feces. middle that makes dividing the tablet in half easier. Some Rectal suppositories can also carry medications meant tablets also have a number or letter code embossed across the for systemic effect. The hemorrhoidal venous network in the tablet’s face for easy identifi cation. rectum readily absorbs medications, at levels comparable to Medicinal powder placed within a gelatin casing is called venous injection, into the central circulation.4-6 Use of rectally a capsule. Capsules are generally easier to swallow and, per- inserted diazepam, available in a gel, is an acceptable means haps more importantly, do not dissolve in the water-based of administering this life-saving medication during status saliva of the mouth very easily. epilepticus when ordinary venous access is unobtainable. Some medicines are altered by the acids in the stomach, making them impotent, whereas some medicines, specifi cally those that are acid-based, can irritate the stomach lining, lead- Injected Medications ing to ulcerations. To protect the medicine and/or the stom- Injectable medications come in either ampoules, generally ach, pharmacists have covered tablets in a protective enteric reserved for single patient use, or vials, intended for multiple coating. Enteric coating permits the tablet to travel, unaltered, patients. Glass ampoules were originally used to store a med- through the stomach and into the intestine for absorption. ication that was volatile and would easily evaporate. A beer The elderly, the infant, and the infi rmed often have dif- bottle might be an example of an ampoule to carry a spirit. fi culty swallowing tablets and capsules. In some cases, it In some instances, the medicine was very valuable, or very is acceptable to crush the tablet, with a mortar and pestle, dangerous, and an ampoule was used to preserve the security or open the capsule and place the medicine in another car- of the medication. To obtain the medicine from the ampoule rier, such as apple sauce. However, not all medicines can in those cases, one had to break the neck of the ampoule, be administered in this way. A clear example would be any making pilferage obvious. Morphine was originally stored in enteric-coated tablet. It is important to refer to the manufac- a tear-shaped cobalt-blue ampoule, in part for this reason. turer’s recommendations and the information available from In a sense, vials are resealable ampoules. Typically, the a pharmacist before altering the form of the medicine. glass container, and now a plastic bottle, has a rubber stopper In some instances, it is desirable to have the medicine which can be breached with a needle and syringe, or a needle- dissolve in the mouth. Such medicines exert a local or topical less system, and a volume of medicine withdrawn. A concern effect (e.g., they may be used to treat sore throats). Medi- with vials is sterility. Whenever the integrity of a container cines intended to dissolve in the mouth are called lozenges. has been breached there is a concern about bacterial con- The lozenge, also called troches, owes its origins to the tra- tamination. For this reason, many intravenous medications ditional French anise candy, called pastilles, popular in the are manufactured in single-use ampoules. More discussion eighteenth century. Like elixirs, medicine mixed in a sweet regarding the use of ampoules and vials is contained further medium is more palatable, which makes patient compliance in this chapter. with the prescription more likely. Troches dissolve and are absorbed in the mouth through the oral mucosa. Medication absorbed into the oral mucosa also enters the central circulation, bypassing fi rst pass metabolism within Street Smart the liver.1–3 First pass metabolism is a chemical degrada- tion of the drug by the liver that markedly reduces the drug’s bioavailability. For this reason, it is sometimes advantageous Generally all drugs used in emergencies are to administer a medication orally (i.e., sublingual or in the clear, except diazepam. Diazepam is yellow. Any buccal pocket). An example of a drug administered in this discoloration of any drug should alert the Paramedic fashion would be nitroglycerin. that the drug is potentially contaminated and should Some antibiotics and natural hormone replacements (NHR) are now carried in a troches. This method of medica- be discarded. tion administration results in drug levels that are comparable Principles of Medication Administration 517 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Drug Measurement and Dosing One of the earliest attempts at standardization was the development of the Troy system. These efforts at standardiza- As drugs become more refi ned and newer, more potent com- tion have also led to a great deal of confusion. For example, pounds are developed, the importance of precise measurements a pound apothecary equals 12 ounces, whereas a pound Troy becomes increasingly important. In the past, medicines were equals 16 ounces (avdp). Avdp is the abbreviation for avoir prescribed in teaspoons and grains, and as a result inaccuracies de pois, a French term meaning “goods sold by weight” and is abounded. Today medicines are prescribed in micrograms, a placed after a notation to indicate that it is avoir de pois. unit so small as to be barely visible with the naked eye. A constant in using systems of measurement was busi- The correct measurement of drug quantity can make ness community needs.7,8 For commerce to occur, industry the difference between a therapeutic dose and a toxic dose, needed a common system to count, with accuracy, the goods between better health and iatrogenic death. Needless to say, sold and bartered in trade. Despite its apparent inaccuracies, it is every Paramedic’s responsibility to try and administer the the common household system remains the predominant sys- correct therapeutic dose of drug to the patient. tem of measurement in the United States and Canada. Systems of Measurement Metric System The ancient Egyptians measured length in a cubit, the distance Advances in science demanded a more accurate system of from one’s elbow to the outstretched thumb. As one might measurement, and so the metric system was born out of neces- imagine, this led to a great number of inaccuracies, However, sity. The metric system, from the Greek word metron, trans- precision was not as important then. As time went on three lated to mean “to measure,” was advanced by the Frenchman systems of standardized measurement would be developed; Msr. Gabriel Mouton in 1670. His system of measurement in order, they were the apothecary, the common household, depended on a universal standard from which other measure- and the metric system. Each took generations to accept and ments could be obtained in units of 10. This system of mea- each took generations to unlearn when the newer system was surement made scientifi c measurements easier to calculate. introduced. In each case, the previous system was phased out The French quickly adopted the metric system and called for in favor of the more precise new system. its international adoption. Many countries followed suit, and Le Systeme Internationale d’unites, the international system of units Apothecary System (noted as SI following the number), became widely accepted in In medieval times, apothecaries would dispense medications. both the scientifi c as well as the business community. A com- The root of the word “apothecary” is the Greek “apotheke,” parison of metric standard measurements to household common which means storing place. Apothecaries were storing places measurements shows their differences (Table 26-1). for different substances (some mineral and some animal) and The standard for length measurement adopted was the compounds that would be mixed by the apothecary on the meter. The meter, originally defi ned as one ten millionth of order of a physician. These apothecaries developed a system the distance from the north pole and the equator, was later of measuring small quantities of medication. An apothecary redefi ned to be the distance that light, in a specifi ed spectrum, is somewhat |
analogous to the modern pharmacist. travels over in 1/299,792,458 of a second (light-second) while Apothecary measurements included the grain (gr), which in a perfect vacuum. equaled the weight of one grain of wheat, and the minim, the Interestingly, the SI unit of volume is not the liter but weight of water equal to a grain. Needless to say, the weight of the cubic meter, the amount of water that could be contained a grain of wheat could vary dramatically, infl uenced by such within one cubic meter. However, the liter has become widely factors during the growing season as drought and fl ood. accepted in both the Americas as well as Europe. A cubic However, without a satisfactory alternative, the apothecary system fl ourished for centuries. Notations in the apothecary sys- Table 26-1 Metric Equivalents of Household tem included the use of a Roman numeral representing the quan- Common Measurements tity after the unit of measurement. This arrangement of notation Metric Household still persists in the prescriptions of some physicians who might note ii, meaning two, indicating the number of tablets. This 0.06 mL 1 drop would be preceded by the letters “ap” meaning apothecary. 1 mL 15 drops 5 mL 1 teaspoon 60 gtt Common Household System 15 mL 1 tablespoon 180 gtt The common household system, also referred to as the United 30 mL 2 tablespoons 1 ounce States customary system, contains such units of measurement 180 mL 1 teacup 6 ounces as the foot, the ounce, and the teaspoon. Some measurements 240 mL 1 cup 8 ounces (e.g., the yard, which equals the distance from the king’s nose 500 mL 1 pint 16 ounces to the tip of his outstretched thumb) were widely accepted despite their obvious inadequacies. 1,000 mL 1 quart 32 ounces 518 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. centimeter (cc) of water equals 1 milliliter (mL) of water; Mathematical Conversions therefore, the two are often used interchangeably. Conversions of metric measurements from one unit to another By convention, all abbreviations of SI units are in low- are relatively simple because all units are based on a factor of ercase. For example, 1 meter is abbreviated 1 m. To recog- 10, either 10 times greater or 10 times lesser. For example, a nize that liters are not SI units, the abbreviations for liters kilogram is 1,000 times greater than a gram and a milligram are abbreviated in capital letters. For example, 1 milliliter, a is 1,000 times less than a gram. Therefore, to change a gram thousandth of a liter, would be properly abbreviated 1 mL. to kilograms, the Paramedic only need move the decimal Also by convention, all quantities of the measurement three spaces to the right: 1 gram equals 0.0001 kilogram. are placed in front of the unit of measurement and noted in Conversely, to change a gram to a milligram, the Para- Arabic numerals, not Greek. For example, 10 liters would be medic need only move the decimal three spaces to the left: noted as 10 L and not L 10. Finally, to decrease confusion, 1 gram equals 1,000 milligrams. a space is always placed between the number and the unit, The key in understanding these conversions is to under- indicating that the metric system is being used. stand the prefi xes that precede the unit. All multiplications above 1 gram are noted in the Greek prefi xes kilo-, hector-, and deca-, whereas all divisions of a gram are noted by the Street Smart Latin prefi xes deci-, centi-, milli-, and micro- (Table 26-2). While most Paramedics can access preprinted tables and personal digital assistant (PDA) devices for Street Smart many drug calculations, every Paramedic should be knowledgeable about how to perform these The abbreviation in the laboratory for micro- (for rudimentary calculations in case the battery in the example, in the measurement micrograms) is PDA dies or the drug sheets are lost. the Greek symbol g. However, this notation is impractical in keyboard-based documentation and potentially confused with mg (milligram). Necessarily, Special Units healthcare providers have adopted the abbreviation The dose of some medications has to be determined by bio- logical assay or bioassay, a method of determining the relative mc to indicate micro- (for example, mcg equals strength of a substance by testing it on an organism. To stan- microgram). dardize these bioassay measurements, scientists have created the international unit (IU). Examples of medications that The importance of accurate drug calculations is rein- are measured and administered in international units include forced by the most recent MedMAX data. MedMAX is an insulin and penicillin. anonymous national database of medication errors. Of 40,936 Insulin is frequently self-administered by the patient. To medication errors reported in 2000, 23% were errors in the decrease errors in converting from metric to international quantity of the dose of the medication given. These errors units, and thus improve patient compliance, special insulin could be, in part, due to miscalculation.9–11 syringes are manufactured which are marked in international The more diffi cult calculations are the conversions of units. Confusion can occur when a Paramedic tries to use a household common measurements to the metric system. standard syringe for insulin administration and mistakenly While common conversion factors are available (Table 26-3), thinks that the measurements on the barrel of the syringe are international units when in fact they are minims, an old Table 26-2 Metric Prefi xes apothecary measure. Standard Weight: Gram Measurement Devices Multiply (Greek) Deca- 10 The timeless medicine glass is the quintessential example of a medicine measurement device. Marked with metric units on Hecto- 100 one side and apothecary units on the other, pharmacists and Kilo- 1,000 families alike have used the medicine glass to measure all Divide (Latin) forms of medicine, from cough syrup to antiseptics. Deci- ÷10 Another traditional measurement device is the medicine Centi- ÷100 dropper. The medicine dropper draws up a precise volume into its stem and the medicine is then dispensed, drop by drop, Milli- ÷1,000 into a substance such as juice or water. Micro- ÷1,000,000 Principles of Medication Administration 519 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Table 26-3 Conversion of Measurements the drug’s concentration. For simplicity of calculation, and in in the Common Household order to establish a common denominator, concentrations are and International Metric System described as the amount of drug in 1 milliliter (mL) of a solu- tion. For example, if the drug on hand is 5 mg of diazepam in Unit US Conversion Unit Metric a 2 mL prefi lled syringe, then the concentration of the drug Inch 26.4 Millimeter (mm) Ounce 28.3 Gram (gm) would be 2.5 mg per mL. To make drug calculations easier Pound 0.453 Kilogram (kg) during an emergency, many pharmaceutical companies now Gallon 3.79 Liter (L) provide the concentration in notations on the sides of the drug box and/or on the prefi lled syringe. Metric Conversion Unit US Millimeter 39.6 (1/25.4) Inch (in.) Dilution Gram 0.035 (1/28.3) Ounce (oz) Kilogram 2.25 (1/0.453) Pound (lb) Some medications (e.g., Solumedrol) lose potency when in Liter 0.264 (1/3.79) Gallon (gal) solution for a prolonged period of time. These medications Note: The symbol for a pound lb comes from the Latin libria meaning scales. are necessarily mixed at the patient’s side in order to ensure Note: The term “mile” comes from the Latin mille passus, meaning a thousand maximum effectiveness. A medication being mixed is called paces. the solute and the liquid that the medication is being mixed into is called the solvent. When combined, the solute and sol- vent make a solution. If the mixture is a one-to-one, one part these conversions are not exact and errors of 10% are not solvent to one part solution, then the resulting drug is said to uncommon. be at 100% strength. The conversion of household common to metric standard In some cases, it is desirable to weaken a drug by dilu- measurements in the fi eld is rare. The medical community in tion. For example, 50% dextrose in sterile water (D50) is too the United States has adopted metric measurements as the hypertonic for a child’s blood but may be all that is available standard and all medications come with metric notation. and on hand. The D50 would then be called the stock solu- tion. To decrease its tonicity, D50 can be cut in half, to make Conversion of Weight D25, by adding an equal volume of sterile water. The result- The exception to the rule regarding mathematical conver- ing mixture would be half-strength, yet have a dilution of 1 to sions is the calculation of the patient’s weight. Patients usu- 3—one part dextrose in three parts of solution (Table 26-4). ally know their weight in pounds, not kilograms, forcing the Paramedic to translate pounds into kilograms. Weight in a Volume The most accurate method of converting a patient’s In some instances, it is necessary for a Paramedic to know the weight from pounds to kilograms is dividing the patient’s amount of a drug in a volume of solution. For example, how weight in pounds by 2.26. For example, a 185-pound patient much dextrose is in a 500 mL bag of Dextrose 5% in sterile would weigh approximately 83.71 kilograms. water (D W)? 5 While this is the most accurate method, it is not the most A percent weight/volume is defi ned as 1 gram of sol- convenient. Many Paramedics prefer to divide the patient’s ute dissolved in 100 mL of solvent to obtain a 1% solution. weight, in pounds, in one-half, then subtract 10% off from Therefore, 5 grams of solute is dissolved in 100 mL of sol- the result. For example, half of 185 pounds would be roughly vent to make a 5% solution. If the total volume of the solution 92 / 0.5, then subtract 9 from 92 for an approximate is 500 mL, and there are 5 grams per 100 mL, then there are weight of 83 kilograms. Such gross estimates of a patient’s 25 grams in 500 mL of D W. 5 weight while in the fi eld are acceptable, provided the esti- mated weight is within 10% of the actual weight. Table 26-4 Drug Dilutions Street Smart C1V1 c2v2 Concentration of stock (C1) 50% The Paramedic should use the more accurate Volume of stock (V1) 50 mL Concentration desired (c2) 25% method of determining weight in any child under the Volume of new solution (v2) x mL age of 8. (50)*(50) (25)*(x) (2,500) (25x) x 2,500/25 v2 = x 100 mL Concentration Therefore, to obtain D25, add 50 mL of sterile water to 50 mL of stock A common fi rst step in any drug calculation is determining solution to obtain a volume of 100 mL of D25. the amount of drug on hand. This is typically referred to as 520 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Elements of a Drug Order Physician orders 20 mg furosemide IV bolus. In the drug box is 40 mg A standard drug order, whether written in a standing order or of furosemide |
(i.e., a concentration of 10 mg per mL). given verbally to the Paramedic, will contain the following 10 mg 20 mg elements: the amount of the drug, the name of the drug, and 1 mL x mL the route that is to be administered. (10) (x) (20) (1) It is important that the Paramedic listen carefully to, 10x 20 and note (preferably on paper), the specifi cations within the 20 drug order. The order has essential information regarding the x 10 necessary calculations which must be performed in order to x 2 mL administer the correct dose to the patient. For example, if the physician gives an order of x mg of Figure 26-1 Proportional method of drug a drug to be given in y number of mg per unit weight over calculation. z minutes, then the Paramedic must calculate the amount on hand, the patient’s weight, and the fl ow rate of this infusion to obtain the correct dose of drug. (i.e., injection, tablet, etc.) is a function of the medication. As related earlier, a drug’s concentration must be known The issue for the Paramedic is determining if there is suf- before it can be administered in almost every case. Therefore, it fi cient drug on hand to administer to the patient. One simple is common practice for Paramedics to obtain this value imme- method, referred to as the proportional/ratio method, exists diately, either by consulting the drug packaging or by calculat- for calculating this value. On one side of the equation the ing the concentration mentally and making a notation. Paramedic lists the order (i.e., what is desired; for example, Similarly, many drugs are weight-dependent, especially 10 mg given intravenously). On the other side of the equa- pediatric medications. Therefore, it is common practice for tion the Paramedic lists what is on hand. The problem the the Paramedic to immediately obtain, either directly from the Paramedic is solving is the x (i.e., the volume that needs to be patient or by estimation, the patient’s weight and then convert given). Through a process of cross-multiplication, the value that weight from pounds into kilograms. is obtained (Figure 26-1). Once those basic values have been obtained, the Para- medic can then review the order at hand. If the order contains Weight-Dependent Drug Order the term “per kilogram” then the patient’s weight must be Calculation of weight-dependent drug doses is simple if the included in the calculation. Paramedic follows the order of calculation in a disciplined, If the term “per minute” is included in the order, then the step-wise fashion. Whenever an order is received for a drug drug must be a solution that is to be infused intravenously and to be given (so many milligrams per kilogram), then the Para- the drip factor of the intravenous administration set must be medic must calculate the patient’s weight fi rst, using one of included in the calculation. By convention, all drug infusions the two methods previously described. Having obtained the are administered via a micro-drip administration set. All patient’s weight in kilograms, the Paramedic proceeds to the micro-drip administration sets, regardless of manufacturer, next step, multiplying the patient’s weight times the dose produce 1 mL per every 60 drops of solution. ordered. The result is the amount of drug that must be admin- istered. The fi nal step for the Paramedic would be to compare the amount of drug on hand to the dose ordered to ensure that Street Smart a suffi cient quantity is available. Then, the Paramedic pro- ceeds to administer that dose. Medications can have two names: proprietary and generic. If this was not confusing enough, some generic names sound alike as well. To decrease Street Smart confusion, and a possible medication error, the Paramedic should always confi rm orders after Since many of the drugs a Paramedic uses are receiving them, using a communications technique administered during an emergency, prefi lled ampoules referred to as echo technique. If the drug name is in are standardized to contain the dose that an average doubt, ask the physician to spell it out. 70-kg patient would need. Therefore, if after a drug calculation the result appears to require 10 ampoules, Standard Drug Order then the calculations should be rechecked. Typically, A standard drug order would mean x amount of drug is a misplaced decimal explains the error. to be given to the patient. The manner in which it is given Principles of Medication Administration 521 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Example for a child who is 52 inches Table 26-5 Calculation of a Continuous tall and weighs 90 pounds Infusion Height For children of BSA Weight Order 126 mL per hour cm in normal height M2 in lb kg Administration set drip factor 60 gtts/mL for weight 180 90 80 1.30 Step 1: x gtts/min 126 mL 60 gtts/mL/60 minutes 160 80 1.20 70 2.0 140 Step 2: x gtts/min 7,500/60 240 70 1.10 60 90 1.8 120 220 1.00 50 Step 3: x 126 gtts/min 85 60 1.6 100 200 80 .90 1.5 75 50 1.4 90 40 * By convention, all microdrop administration sets provide 1 mL for every 190 60 drops. 180 70 .80 1.3 80 40 *1.2 70 170 65 .70 1.1 30 160 60 60 1.0 25 150 30 .60 55 0.9 50 Table 26-6 Drip Factors and Ratios 140 .55 45 20 130 0.8 40 for Common Administration Sets 50 .50 20 0.7 35 120 .45 15 45 30 Drip Factor Ratio 110 .40 0.6 25 Micro-drip 60 drops equals 1 mL 1:1 Macro-drip 10 drops equals 1 mL 6:1 Figure 26-2 Pediatric nomogram. 15 drops equals 1 mL 4:1 20 drops equals 1 mL 3:1 Pediatric Dosing patient. Some Paramedics use the abbreviation TKO, meaning The vast majority of pediatric medications are adjusted for the to keep open, to indicate this minimal infusion. child’s weight. In many cases, the order is given as a weight- In certain circumstances, the patient’s condition requires dependent dose. When an adult dose must be adjusted to a an infusion of a specifi c volume. If the volume is infused pediatric dose, and the pediatric dosing is not available, then rapidly over several seconds or minutes, then the infusion is the child’s total body surface area (BSA) is divided against called a bolus. If the volume is to be evenly administered the adult’s total body surface area (approximately 1.73 meters over the course of an hour, then the infusion is called a con- squared for a six-foot tall, 150-pound adult). The resulting tinuous infusion. percentage is then taken from the adult dose and is roughly equal to the pediatric dose. Continuous Infusion Calculation of a child’s BSA is easy when a pediatric nomogram is used. The Paramedic would obtain the child’s The task facing the Paramedic, once the order for a continu- height and weight, then cross-reference on the nomogram to ous infusion is given, is to determine how many drips per the child’s BSA (Figure 26-2). minute must occur. There are two methods of determining the drip rate for a continuous infusion. Intravenous Infusions The formula method enlists all of the necessary informa- tion into the calculation and the result is a defi ned drip rate. Continuous infusion of intravenous fl uids is frequently To obtain this number, the Paramedic multiples the drip fac- required in the out-of-hospital care of an ill or injured patient. tor of the tubing (every tubing has a drip factor; for example, When the patient’s condition requires that a large fl uid bolus so many drops equals 1 mL), then divides the total by the be infused (e.g., in order to increase a blood pressure for number of minutes that the infusion is to last (Table 26-5). perfusion), then the intravenous fl uid is usually infused rap- The other method is the ratio/factor method. Understand- idly, or wide open (WO). The number of liters of volume- ing that there are 60 minutes in one hour and that a micro- expanding fl uid—traditionally lactated Ringer’s solution drip administration set provides 1 mL for every 60 drops of (LR) or normal saline solution (NSS)—infused should be fl uid, then a 1:1 relationship has been established between adequate to ensure a minimally acceptable blood pressure in minutes to drops and time to volume. It is apparent that, the range of 80 to 90 mmHg systolic is maintained. because of the 1:1 relationship, the number of milliliters per At other times, the aggressive fl uid resuscitation just hour is always going to be equal to the number of drops per described would be inappropriate. However, constant venous minute (Table 26-6). This 1:1 relationship is only true in the access (e.g., for purposes of medication administration) would case where a micro-drip administration set is used. However, be desirable. Without any fl uids infusing, the IV catheter could by understanding this 1:1 relationship, similar ratios can be become occluded by a blood clot. To prevent occlusion, a mini- established for other intravenous administration sets. mal infusion of solution is continued, typically at an infusion For example, if the drip factor of a macro-drip administra- rate equaling 30 mL per hour. The primary purpose of this slow tion set is 15 drops equals 1 milliliter, or one-fourth less drops infusion is to keep the vein open (KVO) in the IV catheter than a micro-drip administration set, then a 4:1 ratio has been 522 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. established between this macro-drip administration set infusion of drug on-hand (1 gram or 200 mg), if a 4:1 mixture can be rate and a standard micro-drip administration set infusion rate. made (i.e., 250 mL or 50 mL), then the clock method can be To use an example, if the order is for 200 mL per hour, used (Table 26-8). then the drip rate with a micro-drip administration set would be 200 gtts per min. However, if a 15 drop macro-drip admin- Weight-Dependent Intravenous istration set was used, then the order, 200 mL/hr, would be Drug Infusion divided by a factor of 4. The resulting drip rate would be Some drugs are so potent that it is important to precisely infuse 50 drops per minute. (i.e., titrate) the drug to the patient’s weight. As complicated Intravenous Drug Infusion as the process sounds, a weight-dependent intravenous drug infusion only adds the patient’s weight to the standard drug Intravenous drug infusions require precise control (i.e., titra- infusion calculations (Table 26-9). tion) of the drug in order to provide the intended effect. Errors, plus or minus the ordered drug infusion, can result in undesirable effects. Before an order for an intravenous drug Table 26-8 Calculation of Intravenous Drug infusion can begin to be administered, the Paramedic must Infusion Rate Using the Clock Method fi rst prepare the solution, or access a premixed solution, then Order 3 mg per minute (3 mg/min) determine the number of drops per minute to be infused. Administration set 60 drops per mL There are two methods of determining the drop rate. The Solution on-hand 250 mL physiologic saline fi rst method, the formula method, requires the Paramedic to mul- Drug on-hand 1 gram tiply the dose in the order given times the drip factor, then times the solution in order to obtain the desired drip rate (Table 26-7). Drip rate X Alternatively, Paramedics can use the clock method to Step |
1: Calculate the concentration determine the infusion rate. By observing a few fundamen- 1 gram in 250 mL 2 milligrams per 1 milliliter tal conditions, the clock method of drug infusion permits the 1,000 gram/250 mL 2 mg/mL Paramedic to mentally visualize a clock with a sweep hand (Conversion to common units makes calculations easier) pointing out the drug infusion rate. When the sweep hand is Step 2: Step up the clock at the 15 second point, that represents 1 milligram of drug at 1 mg 15 drops per min 30 mL/hour 15 drops per minute or 15 milliliters an hour. When the sweep 2 mg 30 gtt/min 30 mL/hr hand is at the 30 second position, it represents 2 milligrams 3 mg 45 gtt/min 45 mL/hr of the drug infusing at 30 drops per minute, and so forth. Foundational to the clock method is the condition that 4 mg 60 gtt/min 60 mL/hr the drug’s concentration is 4 to 1. Regardless of the amount Table 26-9 Weight Dependent Drug Infusion Table 26-7 Calculation of Intravenous Drug Order 5 microgram per kilogram per minute Infusion Rate Using a Formula (5 mcg/kg/min) Order 3 mg per minute (3 mg/min) Administration set 60 drops per mL Administration set 60 drops per mL Solution on-hand 500 mL physiologic saline Solution on-hand 500 mL physiologic saline Drug on-hand 1 gram Drug on hand 1 gram Drip rate X Drip rate X Patient weight 70 kg Formula Order Solution Administration set Formula Order Solution Patient’s weight (kilograms) Drip rate of administration set ÷ Concentration of the drug Step 1: Calculate the concentration 1 gram in 500 mL 2 milligrams per 1 milliliter Step One: Calculate the concentration 1,000 gram/500 mL 2 mg/mL 1 gram in 500 mL 2 milligrams per 1 milliliter (Conversion to common units makes calculations easier) 1,000 gram/500 mL 2 mg/mL 2,000 mcg/mL Step 2: Set up the formula Step Two: Set up the formula Order Drip factor/Drug concentration Order Drip factor Patient weight ÷ Drug concentration 3 mg/min 60 gtt/mL/2 mg/mL X 5 mcg/kg/min 60 gtt/mL 70 kg/2,000 mcg/mL X Step 3: Eliminate like units Step Three: Eliminate like units 3 min 60 gtt/2 X 5 60 gtt 70 min/2,000 X 180 gtt/min/2 X 25,000 gtt/min/2,000 X 90 gtt/min X 10.5 gtt/min X Principles of Medication Administration 523 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. The Paramedic’s failure to convert a patient’s weight Similarly, the Fahrenheit scale does not have water freezing from pounds (household common) to kilograms (metric) is at zero degrees but at 32 degrees. Therefore, to balance the a source of error in some calculations. It is essential that all two scales 32 must be either added or subtracted from the Paramedics convert all units to a common system before per- result. To convert Fahrenheit to Celsius (medical standard forming drug calculations. temperature measurement) the EMS provider must fi rst sub- tract 32 from the number and then multiply the Fahrenheit Temperature Measurement temperature by 5/9. For example, for a temperature of 103°F, subtract 32 and multiply the result by 5/9 to get the tem- A patient’s body temperature has come to be regarded as a perature on the Celsius scale—(103 32) 5/9 (71)5/9 key indicator of a patient’s health or illness (i.e., a vital sign). 39.4°C. The opposite would be true to convert Celsius to A fever greater than 101°F, might indicate the presence of an Fahrenheit. infectious process inside a patient’s body or that the patient’s body has undergone a signifi cant heat stress. A fever greater than 100.4°F but less than 101°F, may indicate an infl amma- Administration of Medication tory response. Regardless of the source of a patient’s elevated The administration of medications may be one of the great- (or depressed) temperature, the body can only tolerate a very est responsibilities that a Paramedic has to perform. Because narrow range of temperature change from its baseline and still of the nature of a medical emergency, Paramedics are per- function. Core temperatures above or below this range can mitted to administer powerful and potentially lethal drugs. lead to cessation of essential metabolic processes and chemi- When given correctly, these medications can help to improve cal reactions critical to all organ function. Understanding the a patient’s condition or relieve some suffering. Given incor- importance of body temperature as a vital sign, Paramedics rectly, the Paramedic may make a bad situation worse. There- often obtain a temperature using a red-dyed alcohol thermom- fore, Paramedics are ever mindful of their responsibilities eter or, more recently, a tympanic membrane thermometer. whenever drugs are being administered. Like nurses, Para- While Galileo Galilei invented the water thermometer in medics practice the fi ve rights of medication administration 1593, then called a thermoscope, the invention of the fi rst (right person, medication, dose, route, and time). The fi ve accurate and functional mercury thermometer was attributed rights simply represent an intelligence, a way of thinking, that to a meteorologist named Daniel Gabriel Fahrenheit in 1714. decreases the potential for medication errors. Using a water and salt solution as a standard, he established The fi rst right refers to the right patient. Although this is a freezing point for the solution, at 0°F, then established the an infrequent request, the Paramedic may be asked to assist in freezing of water alone (30°F) and temperature of the human giving medications to patients with whom he is not familiar, body (90°F). These values (later adjusted to 32°F and 98.6°F, such as during a mass casualty incident, while practicing in an respectively), when obtained by thermometer, established expanded role, or while acting within an emergency depart- a rapid and objective means of assessing a person’s body ment as part of the staff. In those instances, the Paramedic temperature. would be expected to identify the patient. If the patient is Shortly after establishing the Fahrenheit scale, Anders awake, alert, and able to communicate, then a personal iden- Celsius, a Swedish astronomer, replaced the previously used tifi cation may be attempted. If the patient is part of a system salt solution with pure water and again froze and then boiled where personal identifi cation, usually in the form of an iden- the pure water at sea level (standard atmospheric pressure). tifi cation band, is provided, then the Paramedic may check Using these measurements as a baseline, he evenly divided the band to verify the patient’s identity as well as identify the the difference into 100 increments, or a centigrade scale, with patient personally. zero being frozen water and 100 being boiling water. This The remaining rights refer to the actual administration of centigrade scale, also called the Celsius scale, was adopted the medication. At the beginning, the Paramedic will check by an international conference on weights and measures, held to be sure that the right medication is being given. Generic in 1948, as the offi cial temperature scale. medications can have names that either sound alike or are Analogous to the duality of household common and met- spelled similarly. Careful attention to detail, such as the spell- ric measurement systems, the public (particularly in English- ing in the order and the spelling on the medicine container, speaking countries) adopted the Fahrenheit scale whereas the will prevent a medication error. scientifi c community adopted the Celsius scale. It is good practice to verify a medication’s name when it While many thermometers produced have both Celsius is obtained from stock (whether that is a drug box or medi- and Fahrenheit scales imprinted on the glass cylinder, in some cine cart), when it is being measured, and then fi nally when instances a Paramedic may be asked to convert Fahrenheit to it is being administered. This triple check of the medication’s Celsius or vice versa. The most apparent difference between identity is expanded to include verifi cation of the drug’s expi- these two scales is that one is based upon 180 even divisions ration as well as the clarity of the medication in the container. between freezing and boiling, whereas the other is based upon If there is any suspicion of potential contamination, then the 100 even divisions. Therefore, any conversions will necessar- drug should be immediately and safely discarded and a new ily involve a 9/5 or a 5/9 adjustment to make the scales equal. supply of the drug obtained from stock. 524 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. As a drug is being prepared for administration, the Para- The fi nal right, the right time, speaks to the adminis- medic should be attentive to the next right, the right dose. tration of drugs on a repetitive schedule. At fi rst blush, this While measuring a dose of medicine, the Paramedic may be might seem inapplicable to EMS. However, some drugs are at greatest risk of committing an error. given repeatedly in the fi eld in order to obtain and main- As previously mentioned, most emergency drugs are pre- tain a certain therapeutic effect. For example, epinephrine pared so that one prefi lled ampoule will be the correct dose is usually repeated every three to fi ve minutes during a car- for the average 70-kg patient. Unfortunately, patients do not diac arrest until there is a return of spontaneous circulation always weigh 70 kg, so adjustments must be made. Further- (ROSC).12–14 In other situations, medications need to be given more, almost all pediatric medications, a large number of in a specifi c order (i.e., at the right time). For example, during medications for the elderly, and an ever-increasing number of a cardiac arrest, vasopressin or epinephrine always precedes adult medications require weight specifi c dosing. an antidysrhythmic and paralytic drugs follow pre-induction Calculating a weight-dependent dose, described earlier medications. in this chapter, is often diffi cult in the out-of-hospital setting. After being given a drug, the patient is re-evaluated to see Poor lighting as well as patient urgency can lead to unin- if the drug was effective. No exceptions should be made. Even tended errors. The creation of drug charts and use of personal the benefi t of a seemingly innocent drug such as oxygen must digital assistants (PDA) have helped alleviate some of the dif- be followed up with a re-evaluation of the patient’s condition. fi culty of calculating the correct dose. Nevertheless, respon- This re-evaluation, and subsequent documentation of patient sible Paramedics typically confi rm—and then re-confi rm—a response to medication, is so important that some Paramedics drug calculation with another Paramedic. If another provider refer to it as the sixth right, the right documentation. is not immediately available, then communication with the The initials DARE, a simple mnemonic, can help Para- hospital emergency department is advocated. A colleague, medics remember the elements of documentation for every such as a registered nurse or physician’s assistant, seated in medication administration. First, what was the data (D) that a well-lit room with abundant resources at hand (including a was obtained and what action (A) was taken in response to calculator) can offer reassurance to a Paramedic who is alone that data? The documentation of the action, if it was a medi- calculating a critical medication dose. cation administration, should include the drug’s name, the exact dose |
of the drug, and the administration route, as well as the time of administration. After an appropriate interval, usually determined by the drug’s onset of action and peak Street Smart effect, the patient’s response (R) to the drugs is assessed, both subjective and objective information obtained, and an evalu- ation (E) of the effi ciency made. In some instances, the drug To decrease confusion and errors, medication orders may be effective and further treatment is not indicated, while of fractions of a whole are documented as 0.X instead in other cases the drug has to be repeated. of .X (e.g., 0.5 instead of .5). When given orally, they are said as “zero point X.” By adhering to this practice, Medication Routes when an order for a one-half milligram dose of a drug Practical necessity generally determines the route that a med- is heard, it will not be mistaken for 5 milligrams of ication is given. If time is of the essence and it is important the drug. Similarly, whole numbers are listed as the to get a precise dose to a target organ, without risk of fi rst digit (i.e., 1 is 1, not 1.0) and thereby prevent the pass metabolism, then the intravenous route is preferred. If a local effect (e.g., skin preparation for a large bore intravenous accidental administration of 10 mg of a drug. needle) is needed, then a topically applied cream or subcuta- neous injection would be appropriate. Each medication route offers specifi c advantages as well as disadvantages over other The next right, the right route, may seem at fi rst blush to medication routes. Therefore, the route of medication admin- be obvious, as Paramedics usually administer drugs intrave- istration is chosen with an express advantage or specifi c pur- nously. Even when a drug is given intravenously, however, if pose in mind. the drug is not followed by a bolus to clear it from the intra- venous administration set, or external chest compressions are Preparation for Medication not performed to circulate the drug, then the drug will not get to the target organ. In other instances, medications adminis- Administration tered subcutaneously to a hypoperfused patient will not be Regardless of the route of medication administration, whether absorbed and the patient will not benefi t from the medication. it is a local route or a systemic route, the Paramedic must pre- The Paramedic should give heed to the warning (right route) pare both the patient and himself. The patient has the right and consider the method of which he is about to administer a to know what is being done and what medications are being medication in terms of its effi ciency and effectiveness. given. A review of the discussion on informed consent is Principles of Medication Administration 525 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. advised if the Paramedic is unsure of whether—and under Otic Medication what conditions—a patient can give informed consent. Medications applied into the ear are called otic medications. The process of obtaining an informed consent from a While it is rare for a Paramedic to instill medications into a competent patient can be summarized by the mnemonic AIR. patient’s ear, if the occasion should arise the patient should First, the Paramedic must ask the patient if he has any allergies be instructed to tilt the head so that the affected ear is facing (A), particularly to the medication that is to be given. Then the upward. After the correct volume of medicine has been drawn patient should be advised of the intended (I) effect of the medi- into the medicine dropper, the Paramedic would approach the cation. Finally, the patient must be advised of reasonable (R) patient. With the ear canal exposed and no visible drainage or risks associated with the procedure and the medication. After obstruction noted, the Paramedic would place the dorsum of obtaining the patient’s consent, the Paramedic should practice the dominant hand on the patient’s temple with the ear dropper medical asepsis, including hand washing and donning gloves. fi rmly held in the hand and poised over the ear opening. This position prevents the ear dropper from being inadvertently dropped into the patient’s ear if the patient should startle and Street Smart jerk. Grasping the pinna of the ear with the nondominant hand and pulling upward and outward, the medicine can be safely instilled into the ear. If the patient is incapable of cooperat- When asking about allergies, the Paramedic should ing with care, then consider placing the patient in the lateral specifi cally ask the patient about allergies to latex, recumbent position. If drainage is desired afterward, simply since a signifi cant number of patients with chronic have the patient roll over to the opposite side. medical illnesses or healthcare workers have Local Nasal Medication developed an allergy to latex. The Paramedic may The inner mucosa of the nostrils has a rich capillary bed that fi nd it diffi cult to differentiate whether the patient’s is an excellent route for the administration of systemic medi- allergic symptoms were from the medication itself cations, discussed later in this chapter. However, this same or the latex within products used to administer that quality also makes the nose prone to bleeding (a nosebleed is medication. If the patient advises the Paramedic called an epistaxis). Epistaxis is an all-too-common event whenever a nasal pha- that he is latex-sensitive/allergic, then non-latex ryngeal airway or an endotracheal tube is introduced into the products must be used during care. Manufacturers are nostril. Subsequent bleeding can drain back into the hypophar- increasingly removing latex from their products for ynx and into the stomach, inducing nausea and possible regurgi- tation. To decrease the incidence of epistaxis, many Paramedics this reason. prepare the nostril with a topically applied vasoconstrictor, such as phenylephrine (Neosynephrine®). Placing the tip of an atom- izer into the intended nostril, the atomizer bulb is given one or Local Routes two squeezes, propelling the medicine against the mucosa. Local routes of medication administration are intended to tar- Following this application of a local vasoconstrictor, some get a specifi c organ or function and confi ne the effects of the Paramedics lubricate the patient’s nares with a topical anes- medication used to that area. For example, medications topi- thetic, such as lidocaine gel. Using a nasal pharyngeal airway cally applied to the eyes are called optic medications. Para- as an introducer, the Paramedic would liberally coat the airway medics occasionally apply a local anesthetic (e.g., pilocaine) and then insert the airway as usual. It is important that the to the eyeball to anesthetize it in preparation for irrigation. Paramedic ascertain if the patient has any allergies to these The eye is an important sense organ and administration errors medications before use. Alternatively, a water-based gel can can lead to blindness. Strict adherence to medical asepsis can be used to lubricate the nare. Under no conditions should a decrease the potential for this complication. petroleum-based gel, such as Vaseline®, be used to lubricate When a medication is an ointment or gel, then a ribbon the nostril prior to introduction of the airway device. of the medicine is placed along the inside of the lower lid. To Phenylephrine and epinephrine (1:10,000) are also used gain access to the inside of the lower lid, the Paramedic should in the treatment of severe epistaxis prior to packing. Approxi- fi rst withdraw the eyelid from the eyeball and then roll the eye- mately 90% of nosebleeds are anterior nosebleeds. Topical lid over a cotton swab, inverting the eyelid in the process. The application of these potent vasoconstrictors provides local ribbon of medication should then be applied from the inner vasoconstriction that helps to decrease bleeding. canthus, proximal to the bridge of the nose, outward. To avoid the risk of cross-contamination and infection, Local Oral Medications optic drops, ointments, and disks are single-patient use only. Like the nose, the mouth has a capillary-rich mucosa that After use, the medication should be immediately discarded to will rapidly absorb any medicine and distribute it systemi- avoid any opportunity for re-use. cally. Systemic medications are typically placed in the buccal 526 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. pocket of the cheek or underneath the tongue in the sublingual rapidly absorb medications. It drains into the lingual vein and space. This route of medication administration is discussed in then into the systemic circulation, sometimes at levels com- further detail later in the chapter. However, the implication parable to intravenous injection. is clear. Large doses of topical oral medication can have a A distinctive advantage of sublingual medication admin- systemic effect and the patient should always be monitored istration is that it bypasses the liver and thus avoids hepatic carefully for untoward effects. fi rst pass metabolism.15 Some medications are extremely sen- Various forms of topical oral medications are available. sitive to this fi rst pass metabolism; for example, a healthy Gargles, such as a salt-water gargle, can be used to cleanse the liver inactivates approximately 90% of oral nitroglycerine.16 mouth of contaminations, such as a blood splash, as well as dilute Furthermore, variations in blood fl ow, including hypotension- any potential pathogens. Hard lozenges and troches are designed induced shock-liver, as well as variations in hepatic enzyme to dissolve in the mouth, extending the duration of contact that activity, secondary to competition, make the drug’s metabo- the medicine has with the mucosa, perhaps to sooth ulceration. lism in the liver unpredictable. Sublingual medication can be given as either a liquid or a Topical Medications solid (pill). The Paramedic starts by lifting the tongue (assis- While a variety of options are used to apply medicine to the tance with a tongue blade is helpful) and depositing the medi- skin, such as liniments and lotions, and for a wide variety of cine into the sublingual space. If the medication is a tablet or purposes, from muscle aches to sunburn, Paramedics typi- pill, it must dissolve to be effective. If the patient lacks saliva, cally do not apply many topical medications. The exception a squirt from a pearl of sterile water can provide the needed may be the application of a topical antibiotic at the inser- solvent to accomplish liquefaction of the medication. tion site of an intravenous catheter. The benefi ts of topically Patients who have received sublingual medication should applied antibiotic ointment are discussed in Chapter 27. be discouraged from smoking immediately afterward. Nico- tine present in the smoke will produce vasoconstriction, hin- Other Local Routes dering the absorption of the medication. For completeness, both douches and enemas should be men- tioned. Paramedics rarely perform either of these procedures Buccal Route unless they are acting in an extended role. Both douches Administering medications using the buccal route is similar (solutions introduced into the vagina via an apparatus) and to administering medications sublingually. In cases in which enemas (solutions similarly introduced into the anus via an the patient has diffi culty with lifting the tongue to the roof of apparatus) instill these solutions into those body cavities. the mouth (e.g., following a stroke), then the medication can Adding a medication to these solutions can provide a local be placed in the buccal pocket created by the cheek. Plac- therapeutic effect, such as when treating a yeast infection. ing drugs in the buccal pocket has been a common practice since antiquity. Peruvian Indians used to stuff chewed coca Routes for Systemic Medications leaves into their buccal pockets, thus absorbing the stimulant directly into the bloodstream. |
Tobacco has also been placed in Medications can have a local effect or they can have a sys- the buccal pocket, as tobacco chew, and the nicotine absorbed temic effect (i.e., an impact on more than one internal organ into the central circulation. system). Medications that are intended to have a systemic effect may be given via the gastrointestinal tract or via an Oral Route injection. The fi rst route, also referred to as the enteral route, is more common and includes taking oral medications, in Clearly, the vast majority of medications that are self- the form of pills, as well as suppositories. The second route a dministered are swallowed. The medication—solid pill, bypasses the gastrointestinal system and is called the paren- capsule, or liquid—is then absorbed into the gastrointestinal teral route. The parenteral route is preferred during an emer- tract where it is passed, via the portal circulation, through the gency because of the rapidity of onset of the medication’s liver and on into the central circulation. The image of a nurse action as well as predictability of the drug levels. passing pills in a paper medicine cup, also called a souffl é The next section reviews the enteral route of drug admin- cup, leaps to mind when one thinks of hospital care. However, istration, from head to toe, followed by a discussion of the Paramedics seldom use this route to administer medicine. parenteral routes of medication administration by inhalation First, the absorption of medications via the gastrointesti- and injection. nal route can be protracted and erratic. Local conditions such as the presence or absence of food, stomach acidity, gastric Enteral Drug Administration motility, and mesenteric blood fl ow all infl uence drug absorp- tion. Perhaps more importantly from an EMS perspective, the Sublingual Route patient must be able to maintain the airway independently and The fi rst enteral route to be discussed is the sublingual route. swallow the medication. Paramedics are often called to the The lingual space is an area inferior to the tongue. The fl oor scene of a patient who is semiconscious, making this route of the sublingual space has abundant capillaries which can impractical. Principles of Medication Administration 527 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Gastric Tubes One means of passing medication to an obtunded or coma- Street Smart tose patient is via a gastric tube. Gastric tubes have been used for decades to administer medications and treatments, and for Gastric tubes can also be passed directly through a variety of other purposes, but have only recently seen use the abdominal wall via a surgical stab wound. A in the fi eld. John Hunter was credited with inventing the fi rst gastric Paramedic may be called to care for the patient tube in 1869, using the skin of an eel to pass liquids into with an indwelling gastrostomy tube which has the stomach of a patient who had diffi culty swallowing (dys- been misdirected or even accidentally removed. phagia). Subsequently, Matas and Meyer used gastric tubes to treat paralytic ileus, a common post-operative complication. The Paramedic should not attempt to replace the The purposes of a gastric tube are numerous. Gastric gastrostomy tube without special training. tubes can be placed to instill feedings (either intermittently or continuously), as well as instill medications (either liquid or solid drug that is pulverized and then mixed in a liquid placement, verifi cation of placement, and either evacuation carrier). One of the earliest gastric tubes, called the Levin of the stomach or instillation of medications. tube, is a simple red rubber catheter that is often placed for A rudimentary understanding of fl uid dynamics is needed this purpose. before the Paramedic selects the appropriate tube. Fluids tend Gastric tubes can also be used to remove air; decompress- to fl ow from areas of higher pressure to areas of lower pres- ing the stomach. Insuffl ation of the stomach during ventilation sure, measurable as milliliters per hour (mL/hr). Naturally, the of the unconscious patient frequently requires the placement thicker the fl uid, the more pressure is needed to cause fl ow. of a gastric tube to decompress the stomach and permit more The viscosity of the fl uid, and the resultant friction, plays a effective ventilation. Decompression of the stomach with an large role in the selection of the proper tube. The speed of the orogastric tube is important for ventilation of children. Over- fl ow is a function of the pressure that is being exerted upon it. infl ation of the stomach in a child decreases diaphragmatic Pressure is measured as the height that a column of water or excursion, increases resistance to ventilation, and decreases mercury would raise under the same pressure and is labeled compliance, culminating in decreased effi ciency in ventila- either cm H O or mmHg. 2 tion of the child. For this reason, it is routine practice to insert The diameter of the inner portion of the tube (the lumen) an orogastric tube during pediatric intubation. also contributes to the friction loss. The smaller the tube, the Gastric tubes can also be used to remove liquid and small greater the friction loss. Therefore, greater pressure will be bits of solid matter from the stomach, such as pill fragments.17 needed to create fl ow. Gastric tube lumens are measured in Evacuation of the stomach using a large diameter tube, such the French scale, where a smaller number means a smaller as an Ewald tube, may be a part of decontamination after a lumen. The length of a gastric tube also contributes to friction potentially lethal ingestion. loss. However, since the lengths tend to vary marginally, the In addition, gastric tubes can be used to compress the contribution of length of the gastric tube is often discounted. inside of the stomach and the esophagus. Bleeding from Most Paramedics insert an orogastric tube in order to esophageal varices or gastric ulcers can be signifi cant and evacuate or decompress the stomach. The application of suc- potentially life-threatening. Use of a special gastric tube, called tion to the end of an orogastric tube can effectively accom- a S engstaken-Blakemore tube, permits the Paramedic to apply plish this function. Suction, a pressure that is less than direct pressure, internally, to the source of bleeding.18,19 atmospheric (a negative pressure), creates a fl ow in a fl uid, A gastric tube may be inserted either orally or nasally. either gas or liquid. Most ambulances and portable suction Nasogastric tubes are typically inserted into patients who are units can provide substantial continuous suction, greater than awake, those with an intact gag refl ex, or those for whom the 180 mmHg. gastric tube is expected to be long-term. However, application However, continuous suction will cause a single-lumen of a local anesthetic (e.g., Hurricane spray®) can deaden the gastric tube, such as a Levin tube, to adhere to the gastric gag refl ex and permit passage of the gastric tube orally in an mucosa, leading to local irritation and bleeding. To prevent awake patient. Alternatively, a gastric tube may also be passed this predictable complication, dual-lumen tubes (such as the orally in the obtunded or unconscious patient. This is the most Salem sump) were invented. Dual-lumen gastric tubes always common route and the preferred route for EMS providers. have one port open, a port that entrains air into the stomach As in all procedures, the Paramedic should fi rst discuss and prevents suction from adhering to the stomach wall. the procedure with the patient, inquiring about allergies, If a dual-lumen tube is not available, then intermittent advising the patient of the intended effect, and warning the suction can be accomplished by periodically turning the suc- patient about reasonably expected side effects. tion off, allowing the gastric tube to dislodge. Healthcare The process of orogastric tube insertion includes facilities frequently have wall-mounted suction devices which selection, preparation, and measurement of the tube; tube permit intermittent suction for this purpose. 528 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Alternatively, an OG tube is directly advanced over the Street Smart midline of the tongue until the posterior pharynx is reached. Care should be taken to not strike the posterior pharynx as it might elicit a gag refl ex. If the blue atmosphere port of a dual-lumen gastric The gastric tube, now in the proximity of the posterior tube is lower than the stomach, stomach contents pharynx, is ready to be passed. If the patient is willing and will drain through the atmosphere port by gravity. As able to cooperate, then ask the patient to sip a glass of water happens on occasion, the Paramedic may unwittingly through a straw. This facilitates the passage of the gastric tube into the esophagus by closing the glottis over the trachea, allow the tube to fall to the patient’s side. thereby preventing accidental tracheal intubation. Subsequently the tube drains the stomach contents If the patient has persistent paroxysms of gagging and onto the Paramedic’s shoes and/or the fl oor. To retching, then visualize the posterior oropharynx with a pen- light. It is not uncommon to fi nd the gastric tube coiled in prevent this complication, the tube should be plugged the posterior pharynx. In that case, withdraw the gastric tube and the tail of the tube pinned to the patient’s until it is unfurled and then proceed once more. clothing near the collar. Once the gastric tube is in the esophagus, approximately one-half the length of the measurement, then the gastric tube should be advanced briskly. If the patient begins to cough, then Initially, preparation for gastric tube insertion entails col- the gastric tube may be in the trachea and pressing against the lecting the necessary equipment fi rst. Either a single-lumen carina. Withdraw the tube approximately 6 inches and retry. gastric tube (such as a red rubber Levin or an Ewald tube), After the gastric tube has been completely passed, then or a dual-lumen gastric tube (such as a Salem sump) should its placement must be confi rmed. The Paramedic would fi rst be chosen. All gastric tubes are approximately 50 inches draw up 10 to 20 mL of air in a slip-tip syringe and place it at (127 cm) long and come in sizes 12 to 18 French. An average the distal opening. The Paramedic would then place a stetho- adult will accept a 16 French gastric tube. scope fi rmly against the epigastrium and instill the air into the If the nasogastric route is to be attempted, a tube of water- tube. If the gastric tube is properly placed, then a swooshing sound will be heard over the epigastrium.20-22 soluble lubricant should be available, as well as towels, emesis basin, soft-tip or covered clamps, a large syringe (30 mL), and The same sound will not be heard over the lungs; therefore, a stethoscope. auscultating the lungs may not be a reliable indicator of misplace- After obtaining the necessary consent, the patient is ment. Instead, the Paramedic should ask the patient to speak. placed in the high-Fowler’s position. If the patient is unable A gastric tube misplaced into the lungs will separate the vocal to be placed in the high-Fowler’s position, then the patient cords and the patient will have diffi culty speaking (dysphonia). can be placed in the left lateral recumbent position. Finally, the Paramedic should aspirate the gastric tube. If a nasogastric tube is to be inserted, then the Paramedic The presence of gastric contents is proof positive that the gas- should fi rst visualize |
the external nare and choose the largest tric tube is in the right place. Other signs of a misplaced tube nostril, avoiding nasal polyps or a deviated septum. Premedi- include condensation in the tube as well as dropping pulse cation with phenylephrine and lidocaine gel, as previously oximetry readings, indicating desaturation of the blood. described for nasopharyngeal airway insertion, will reduce The gastric tube can then be attached to wall suction the trauma associated with this approach. and low suction can be applied, approximately 90 mmHg. Next, the gastric tube must be premeasured. A nasogastric The patient should be continually monitored throughout this (NG) tube is measured from the bridge of the nose to an earlobe, procedure. Signs of hypoxia, such as premature ventricular then from the earlobe to the xiphoid process. An orogastric (OG) contractions (PVC), and altered level of responsiveness may tube is measured from the corner of the lips to the xiphoid pro- indicate that the gastric tube is misplaced into the trachea, or cess instead. Once measured, the Paramedic should make note of has migrated from its original position into the trachea, and the measurement. Most gastric tubes have incremental markings, the suction is drawing air out of the lungs. consisting of black bands placed every so many centimeters. Once placement of the gastric tube has been confi rmed, Once the tube is measured and the patient prepared, the the Paramedic should proceed to secure the gastric tube to pre- Paramedic then lubricates the last 6 inches of the gastric tube vent accidental displacement. An approximately 6-inch piece with a water-soluble gel, and proceeds to pass the tube. An of 1-inch tape placed in a chevron fashion over the nose will NG tube is advanced perpendicular to the plane of the face secure the NG tube. An OG tube can be secured to the corner and directly into the nares. If resistance is felt, then the tube of the mouth with a tie-wrap, similar to an endotracheal tube. should be slightly withdrawn, approximately 1 inch, and then Alternatively, if an endotracheal tube is in place, then the OG rotated in the fi ngers 90 degrees. Then another attempt should tube can be secured to the endotracheal tube itself. be made. A twisting action with the tip of the tube will help On occasion, the fl ow from the gastric tube may stop, sug- the tube pass over the turbinates in the nose. gesting that the gastric tube is not functioning. Under those conditions, the Paramedic should disconnect the suction and Principles of Medication Administration 529 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. reassess placement to eliminate the possibility of displace- ment. If the gastric tube is not displaced, then the Paramedic Street Smart should assess the gastric tube for obstructions. To accomplish this, the Paramedic irrigates the gastric tube. To irrigate a gastric tube, approximately 30 mL of saline or sterile water Continuous seizures in children (pediatric status is instilled into the tube via a syringe. If a great deal of resis- epilepticus) can be life-threatening. Diazepam is tance is met, then the Paramedic should clamp the gastric the drug of choice to terminate the convulsions, tube closed. and the rectal route is a viable alternative for its For ease during transfer, the patient can be disconnected administration.23,24 from the suction and the gastric tube clamped. The atmo- One form of diazepam comes as sphere port of a dual-lumen gastric tube (the blue pigtail on a a gel. It is convenient for rectal administration, and Salem sump) can be connected with the other port, making a actually comes with a rectal administration device. closed circuit. Soft-tip clamps can be used for single-lumen Lacking commercially available gelled diazepam, gastric tubes, but care should be taken to ensure that the teeth of the clamp do not perforate the wall of the gastric tube. the Paramedic can, using a 3½-half inch intravenous needle, improvise a rectal administration device. Rectal Route After withdrawing the needle, the Paramedic attaches Although Paramedics rarely use the rectal route for a medica- the hollow plastic catheter to the ampoule of tion administration, the rectal route has a number of distinc- diazepam and proceeds as normal, passing the plastic tive advantages that make it a desirable site for medication catheter into the child’s rectum and depositing the administration. The rectum has a rich blood supply via the hemorrhoidal venous plexus. Drugs that are absorbed from medication. the rectum avoid inactivation by stomach acids and intestinal enzymes. In fact, 50% of the absorbed drug bypasses the por- tal circulation, minimizing the impacts of fi rst pass metabo- Parenteral Drug Administration lism and biotransformation. These factors, in combination, When a rapid onset of drug action is required (e.g., during allow for comparable drug levels between intravenous admin- an emergency), the most direct route to the target organs istration and rectal administration. The rectal administration sidesteps the gastrointestinal system (enteral administration) route is also useful when the patient is unable to accept oral and enters drugs directly through the central circulation. This medications, such as in the case of infants or if the patient has administration route is called the parenteral route because it persistent vomiting. goes around the gastrointestinal, or enteral, system. Before administering medication using the rectal route, Parenteral drug administration has several distinct advan- and after obtaining consent, the patient must be properly tages over enteral drug administration. Enterally administered positioned. The Paramedic should ask the patient to assume drugs have to be absorbed from the lumen of the intestines a left lateral recumbent position. Once in that position, the where absorption can be erratic. Gastrointestinal drug absorption patient is asked to bring her right knee to the chest as far can also be adversely affected by a number of factors, includ- as practical. The Paramedic should then take care to only ing the presence of gastric secretions, mesenteric circulation, expose what is necessary to accomplish the task at hand, gastrointestinal motility, co-ingested foodstuffs, and a host of while leaving the remainder of the body covered. This mod- other variables.25–27 Drugs deposited into the intestines are also ifi ed left lateral position, called the Sim’s position, provides acted upon by a number of enzymes which can immediately optimal access to the anus while minimally compromising deactivate certain drugs. Conversely, drugs administered via the the patient’s dignity. parenteral route circumvent all of these factors, plus they avoid With the patient in position, the Paramedic would then the liver’s fi rst pass metabolism. Therefore, parenterally admin- take a well-lubricated suppository, or rectal medication istered serum drug levels are more predictable than enterally administration device, and insert the device into the rectum administered serum drug levels for these reasons. approximately 4 inches in adults and 2 inches in children. Finally, drugs administered parenterally can be given The Paramedic should ask the patient to breathe through her to patients who are uncooperative or incapable of coopera- open mouth to help her relax during medication administra- tion (i.e., unconscious). These several advantages combine tion. Once the medication administration device is in place, to make parenteral drug administration routes the preferred the medication is deposited in close proximity to the hemor- drug route in an emergency. rhoidal venous plexus. On occasion, as the medication administration device is Intranasal Route advanced, the Paramedic may feel resistance from a stool that A medication administration route recently adopted by Para- is within the rectal vault. In that case, the device should be medics, is the intranasal route. The intranasal route takes withdrawn and an alternative route considered. advantage of the nasal passages. These nasal passages are 530 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. lined with very vascular mucous membranes which can Table 26-10 Intranasal Medications absorb medications quickly and have a shared connection with the brain. This allows these medications to go directly Drug Use to the brain, without the risk of fi rst pass metabolism associ- Atropine Organophosphate poisoning ated with enteral routes of drug administration.28–30 This fac- Epinephrine Cardiac arrest tor makes intranasal medication administration desirable for Fentanyl Pain management Paramedics under certain conditions. Glucagon Hypoglycemia For example, the combination of a patient with altered Infl uenza Flu prophylaxis mental status, especially one who is combative, and/or a mov- ing ambulance can make obtaining intravenous access diffi cult. Insulin Hyperglycemia/Crush injury The intranasal medication route, which is both quick and easy, Lidocaine Cardiac arrest makes success under these trying conditions more likely. How- Midazolam Seizure control ever, the clear advantage of intranasal administration of drugs Naloxone Opiate overdose is the decreased risk of accidental needle injury. The federal Nitroglycerin Hypertensive crisis/acute coronary syndrome Centers for Disease Control and Prevention (CDC) estimates that as many as 600,000 needlestick injuries may occur annu- Steroids Reactive airway disease ally in the United States. With minimal training, a Paramedic can effectively and safely administer medications while avoid- ing needlestick injury. In some cases, newer Paramedics can Cultural / Regional differences be trained just before use (called “just in time training”). The use of intranasal medication administration technol- In some regions, a common street practice is to mix ogy, a truly needleless system, is an example of an “engi- neered control.” Engineered controls are means of preventing cocaine (an upper) with heroin (a downer), a practice exposure to potentially infectious materials (PIM). In this called speedballing, snowballing, or smack and crack. case, the risk of exposure is through accidental needlestick. The intended effect is to fi rst get high, then “coast” Prevention methods are mandated by OSHA and intranasal down with the heroin. Some “double” inject the two medication administration is consistent with the intent of the Needlestick Safety and Prevention Act of 2000.31 drugs, whereas others inject the heroin and inhale, One drug that shows promise for Paramedic practice is or snort, the cocaine through the nostrils. When naxolone (Narcan®). A study in Denver’s EMS demonstrated the heroin, or co-ingested substances like alcohol, that naxolone can be safely and effectively administered to patients who are suspected of opioid overdose.32 Paramedics depress the respiratory system, the Paramedic could in Denver administered 1 mg in 1 mL per nostril of naxolone consider the use of intranasal naxolone to reverse to patients who met the criteria. For those with suspected opi- the opioid-induced respiratory depression. However, oid overdose, the mean response time was 3.9 minutes. As a if the cocaine was snorted, then the vasoconstrictive result, the Denver Paramedics started 29% fewer IV lines in that patient population. effects of the cocaine may prevent the absorption of However, the use of intranasal naxolone is considered an the naxolone. off-label use. The term “off-label use” implies that using the drug in that manner has not been approved by the federal Food and Drug Administration (FDA), which requires experimental Obtaining intravenous access while a patient is having an studies to approve a drug or the use of a drug in another man- unremitting seizure, a condition called status epilepticus, can ner. In some cases, pharmaceutical companies are not willing to be diffi cult. Intranasal administration of anticonvulsants, such underwrite the expenses of experimental studies for non-patent as midazolam, would be advantageous in controlling the sei- drugs. This should not be construed to mean that a drug cannot zure. One study of intranasal midazolam showed that it had a be used in this manner. Physicians, during the practice of medi- 73% bioavailability when compared to intravenous administra- cine, can order drugs administered in an off-label use. Some tion33 and that it |
had the added advantage of rapid onset. drugs can be given intranasally, some off-label (Table 26-10). The volume administered intranasally should be no more Respiratory Route than 1 mL of liquid and the drug should be atomized to a par- Inhalation of medications has several distinct advantages ticle size of between 10 mcg and 50 mcg, the optimal particle over other means of medication administration. Inhala- size for absorption. Currently several different devices are tion of a drug-laden vapor can quickly lead to therapeutic available that can meet these operational criteria. Contraindi- drug levels in the bloodstream via absorption through the cations for use of intranasal atomizers for medication admin- c apillary-covered alveoli. Inhalation also avoids fi rst pass istration include epistaxis, septal wall defects, and intranasal metabolism in the liver, allowing a rapid buildup of the drug cocaine use. in the systemic circulation. This method avoids the use of Principles of Medication Administration 531 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. needles, thus lessening the threat of blood-borne pathogens a reduction in the velocity of airfl ow cause particles between for the Paramedic. 6 and 20 microns to “fall out” in the nose and particles greater Inhalation therapy also has several drawbacks which tend than 6 microns to fall out in the trachea. As the pulmonary to reduce its effi ciency. Inhalation therapy requires that the tree divides further, more fallout occurs; particles greater than patient be able to assist with treatment (i.e., perform inhala- 2 microns fall out in the bronchi and 2 micron particles fall tion). A lack of coordination is the most frequent cause of out in the bronchioles. The result is that nearly particulate- ineffectual breathing treatments. Inhalation therapy is also free air enters the alveoli.36,37 dependent upon the patient’s breathing pattern, particularly While fallout generally serves a protective function, act- upon the period of holding one’s breath during inspiration. ing as a particle trap to keep contagions and pollution out of the lungs, it also tends to keep large droplets of aerosolized Pulmonary Treatments medications from penetrating the terminal bronchioles and To a large extent, the treatment of pulmonary disorders from distal alveoli. This dramatically reduces the effectiveness of asthma to emphysema is focused on the delivery of respira- many respiratory drugs. tory agents directly into the pulmonary tree. These broncho- To complicate matters further, the propellants used to dilators, such as albuterol (Ventolin®), and anticholinergics, deliver these medications use cold gasses (room temperature such as ipratropium bromide (Atrovent®), are inhaled using gasses) to deliver these medications into the bronchi. Upon one of the several respiratory therapy devices discussed later contact with cold air, the bronchi and bronchioles refl exively to provide immediate relief from bronchospasm. Other respi- spasm air to protect the sensitive alveoli. Paradoxically, the ratory drugs, such as the anti-infl ammatory drug cromolyn respiratory medications which are given to treat broncho- sodium, and even antibiotics, such as tobramycin, can be spasm can induce more bronchospasm. inhaled to treat respiratory disease. Metered Dose Inhaler In the past, the majority of inhaled medications were The metered dose inhaler (MDI) remains the gold standard designed to exert a local pulmonary effect and to treat reactive for respiratory therapy. Portable and simple to operate, the airway disease. Currently, research is underway to administer MDI enjoys a high degree of patient acceptance. This is due vaccines and other antimicrobial treatments which would have in part because it does not require extraordinary breathing a more systemic impact via the pulmonary system. There is maneuvers. Also important to the Paramedic is that the sealed even development and study of an inhaled insulin (Exubera®) pressurized unit is tamper-proof and its contents are protected which uses the capillary-rich lung fi elds to absorb powdered from degradation by light and water. insulin instead of requiring subcutaneous injection.34,35 While the MDI is a preferred personal respiratory treat- ment platform for many, it is relatively ineffective, depositing Personal Protective Equipment less than 20% in the distal lung fi elds. To improve effi ciency, Drug-ladened exhaust from the various respiratory treatment as well as to assist those patients with abnormal breathing pat- platforms present the Paramedic with a potential threat. To terns, a spacer device can be utilized.38-40 The spacer allows a minimize that threat, the federal Centers for Disease Control more controlled inhalation of smaller, ideal-sized drug particles and Prevention (CDC) recommends that Paramedics use a suspended in the vapor within the chamber (see Figure 26-3). mask and gloves while administering these medications. EMS Dry Powder Inhalers vehicles should also be designed so that stale air in the patient compartment is expelled and fresh air circulated frequently. Dry powder inhalers (DPI), such as the Diskhaler®, use a solid In some cases, where vapor is visible, it may be reasonable for drug which is pulverized into micro-fi ne particles for inhala- a Paramedic to wear eye protection, such as a splatter shield tion. The DPI, while an effective platform for the delivery of or goggles, while in close proximity to the patient. pulmonary medications, depends upon the patient’s inspiration for uptake of the drug and proper dispersal of the drug across Fluid Dynamics the lung fi elds. If the patient has a reduced inspiratory fl ow, less Air, like water, is fl uid and is subject to laws of fl uid dynam- than 60 L/min, then the drug will not reach the distal alveoli. ics. For example, the more resistance air encounters (e.g., in a narrowed airway), the more turbulent the airfl ow. Turbulent airfl ow is slower. The structure of the lungs takes this fact into Street Smart account and the airways divide some 23 times before they reach the alveoli, allowing nearly non-existent airfl ow at the Healthcare providers have complained of headaches, alveolar level. This dead air in turn permits easier diffusion of bronchospasm, and conjunctivitis from secondhand gasses such as oxygen and carbon dioxide. The slowing of air in the airways also serves another pur- exposure to the dust exhausted from a DPI. Use of PPE pose—it encourages fallout. Fallout occurs whenever large can help to reduce the incidence of passive exposure particles carried in the air current settle out as airfl ow velocity to the droplets. is lost. An example of this is dust settling out. Turbulence and 532 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Figure 26-3 Use of an MDI with spacer. Small Volume Nebulizer The small volume nebulizer (SVN) is an alternative plat- form for the delivery of inhaled medications. More diffi cult to set up and operate, it is thought to produce a better particle size for inhalation. Hypothetically, more of the drug is depos- ited in the patient’s alveoli. The medication is suspended in a stream of air which is then smashed against a round surface in the SVN. The resulting liquid shear creates micro-fi ne particles, in the 1 to 3 micron range, which are ideal for inhalation. Three factors combine to alter the effi ciency of this mechanism: jet design, gas pressure, and fl uid dynamics. Figure 26-4 Assembly and operation of the SVN. It is critical that the gas-emitting jet of the SVN has the ideal orifi ce diameter, as well as distance to the baffl e, for assembly, SVN-BVM-ET, changes the conditions under atomization. For an SVN to function properly, the gas pres- which an SVN normally operates. sure must be adequate, but not excessive. In addition, the sur- First, an average 26 cm long, 8 mm internal diameter face tension of the aqueous solution, usually a function of (ID) endotracheal tube decreases dead space from an aver- the liquid’s viscosity, must be within acceptable limits. These age of 75 mL in the trachea to approximately 60 mL, but factors being equal, the SVN is a good platform for the deliv- does so at a cost. The smaller dead space is owed to a smaller ery of pulmonary medications to the patient in respiratory airway lumen. A smaller airway lumen immediately results in distress. greater airway resistance. Greater airway resistance produces Prior to using an SVN, the Paramedic should obtain a greater fallout of the inspired vapor. Decreasing the lumen history from, and perform a physical on, the patient. A dem- of the airway (e.g., from an oral endotracheal tube size of onstrated history of responsiveness to MDI bronchodilators 8 mm to a nasal endotracheal tube size of 6 mm) increases the indicates a greater likelihood of success with the SVN ( Figure airway resistance exponentially, in this case 4.2 times more 26-4). The physical examination should include auscultation resistance. for wheezes or, more ominously, absent breath sounds, as well Resistance is also increased with the higher ventilatory as pulse oximetry. Some Paramedics obtain a baseline peak fl ow rates, typically seen in manual or mechanical ventila- fl ow meter reading as well. Key to assessing the effectiveness tion. The combination of increased airway resistance, and of any SVN treatment is the patient’s subjective judgment airway turbulence, combine to generally cause less medica- regarding her own dyspnea. tion disposition in the alveoli, from a normal of 20% to less than 15%.41 Use of an In-Line Small Volume Nebulizer To defeat these disadvantages, the American Association in Bag-Valve-Mask Assembly of Respiratory Therapists recommends that intubated adult In special circumstances, an intubated patient could benefi t patients, who are receiving respiratory treatments, should be from a respiratory treatment. In those cases, an SVN may ventilated with a smaller tidal volume (< 500 mL). Gentle be attached in-line with the bag-valve-mask assembly. This ventilation with reduced fl ow, as well as the addition of an Principles of Medication Administration 533 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. inspiratory pause at the height of each positive pressure ven- between repeated patient uses. Today, most Paramedics use tilation, should be employed. plastic syringes, prepacked in sterile wrappers, for individual patient use. However, glass syringes are still available for use Topical Route in circumstances in which the drug would adversely react For sustained systemic delivery of a medication, an alter- with the plastic syringe. native administration is the topical route. Medication, con- The components of a hypodermic syringe include the tained within a cream carrier, is applied to the skin and is then syringe and the needle. The connection of the syringe to the absorbed directly into the subcutaneous capillary beds, where needle is called the adaptor and the connection of the needle it passes on to the central circulation. The rate of absorption to the syringe is called the hub. Some needle adaptors attach is variable and dependent upon several circumstances. to the syringe hub by use of a twist connection, called a luer Factors affecting topical medication absorption, also lock, where the adaptor on the syringe is grooved and will called transdermal medicine, include the skin’s vascularity mate with a fl ange on the needle hub. This provides a more and perfusion, as evidenced by capillary refi ll and tempera- secure connection, decreasing the chances of accidental dis- ture (warmth). Furthermore, skin conditions such as rashes, connection. Other syringe adaptors simply slide inside the eczema, and open lesions can also affect absorption. |
needle hub and are called slip-tip adaptors. A number of medications are available in transdermal The shaft of the syringe is called the barrel. Syringes patches including nicotine, hormone replacement, opiate are labeled according to the volume within the barrel analgesics, and nitroglycerine. An example of a topical (i.e., 1, 3, 5 mL) and the calibrations on the side of the barrel. medication applied by Paramedics in the fi eld is nitroglycer- Traditional hypodermic syringes are marked in divisions of ine paste. A Paramedic takes a ribbon of paste, measured in a milliliter, and those would be called a 1 mL syringe, 3 mL inches, and applies it to an impermeable paper barrier which syringe, and so on. Many hypodermic needles have dual cali- is then applied onto the skin. Assuming that the patient bration: tenths of milliliter on one side (metric) and minims is not hypoperfused and/or hypothermic, the medication- (common household) on the other. Paramedics should be laden nitroglycerine cream melts, is absorbed through the cautious and not confuse 0.10 mL with 10 minims, as they epidermis, and enters the subcutaneous capillary beds are not equivalent measures. underneath. Nitroglycerine can have a profound effect on An insulin syringe is an exception to the rule of syringe blood pressure, inducing almost immediate hypotension. marking. Insulin is not administered in milligrams per millili- Therefore, the location of the paste/patch should be in an ter (mg/mL), as most standard medications are, but in interna- easy-to-reach place such as the upper arm or posterior tional units (IU) determined by bioassay. Therefore, a special shoulder. To remove the nitroglycerine paste quickly and syringe, marked in units, is manufactured for insulin injec- effectively, a tongue blade can be scraped across the skin in tion. The insulin syringe looks similar to the 1 mL syringe the direction of hair growth. frequently used for tuberculosis testing. Paramedics should look at the syringe carefully to avoid confusing a tuberculin syringe with an insulin syringe. The purpose of a syringe is to either inject a liquid Street Smart medication out of the barrel or to withdraw blood into the barrel. In both cases, the barrel of the syringe is fi lled with The cream used in the manufacture of nitroglycerine a liquid. When the horizontal surface of a liquid interfaces paste is similar to the conductive medium used for with the vertical wall of the barrel, cohesive forces (i.e., surface tension) tend to pull it away from the wall while manual defi brillation. It is prudent to remove any adhesive forces between the syringe’s wall and the liquid nitroglycerine patch or paste prior to defi brillation/ tend to pull it toward the wall of the barrel. As a result, the cardioversion.42 Failure to remove a patch/paste may liquid moves upward. These two forces—surface tension result in arcing and a loss of defi brillation energy. and wall adhesion—cause the liquid’s surface to form into a concave-curved shape called a meniscus. As a matter of practice, Paramedics compare the bottom of the meniscus with the calibrations on the barrel in order to determine the Injections volume of drug in the syringe. Tools for Injections To facilitate injecting drugs, or withdrawing blood, a plunger is placed inside the barrel. The head of the plunger The quintessential tool for parenteral drug injection is the is fi tted tightly inside the barrel, thus preventing liquid from hypodermic syringe. Whether it is used for a subcutaneous seeping past the plunger. However, on occasion, an imperfect injection, an intramuscular injection, or to gain intravenous match will occur. If this happens, liquid will seep past the access, a syringe is a key component of the assembly. plunger and drip the drug onto the Paramedic’s hands. For In the past, glass syringes with calibrations carefully this reason, Paramedics are advised to always wear gloves etched on their sides were used in the hospital and sterilized whenever a syringe is used. 534 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. At the apex of the plunger’s head is a convex head. The a given volume of liquid at a faster rate. To reduce the pres- head’s shape is intended to offset the meniscus, leaving a fl at sure being applied, the Paramedic may alternatively choose a surface that is easier to measure. In the past, nurses would larger diameter (smaller gauge) needle. draw up approximately 0.1 mL of air, an air bubble, into the The length of a needle, the other physical characteristic syringe to offset the effect of the meniscus. However, the con- of a needle, is also typically a function of the task at hand. A vex head of the plunger corrects this problem, making the shorter needle, approximately 1 inch, is used when injecting a practice unnecessary. If the plunger head is convex, then the drug into the medication port of an intravenous set. By using Paramedic should measure the volume of drug from where a longer needle, the Paramedic would risk bypassing the pro- the plunger touches the barrel of the syringe. tection afforded by the hard plastic of the medication port and To administer a liquid drug, the Paramedic merely has piercing the tubing’s soft sidewalls. to push down on the shaft of the plunger to push the drug A longer needle is used when an intramuscular injection out of the syringe. However, the pressure applied to push the of medication is given to an obese patient. In some cases, a drug out can cause the patient some discomfort. To ease the needle as long as 4 inches is needed so that the medication patient’s pain and to give the Paramedic added control of reaches the muscular layer. the syringe, most syringes have a fl ange at the top. By plac- A needle is essentially a hollow wire which is cut to ing her fi rst and second fi nger under the fl ange and pushing length. The end of the wire is often cut obliquely, in such a upward on the fl anges while simultaneously pushing down- fashion that a sharp leading edge is created, called the point. ward with her thumb on the plunger, the Paramedic can con- The sharper the point, the easier the needle will enter into the trol both the rate of administration as well as the pressure patient’s skin or the stopper in a vial. applied to the patient’s skin. The needle now has an angled surface called the bevel. The bevel, the angle of the needle point, is calculated for Hypodermic Needle a specifi c purpose. A regular bevel is designed to quickly The heart of the hypodermic syringe is the needle. Needles pierce the skin with a minimum of pain. A Huber bevel is are generally made of surgical-quality stainless steel and intended to pierce a stopper without coring it, preventing may be either pre-assembled with the syringe or individually leakage of the contents within the catheter from leaking out packaged in a sterile wrap. The parts of the needle include the of the stopper when the needle is withdrawn. Blunt bevels, hub and the shaft. The hub, generally made of plastic, has an used for intradermal injections, are designed to deposit the external fl ange designed to mate with the syringe adaptor. medication just below the skin without penetrating deeper Like syringes, needles come in a variety of sizes and layers of skin below. lengths, each according to their intended purpose. Needles are measured in gauges—the smaller the number means the larger Needle Safety the diameter of the needle (e.g., 14 gauge > 20 gauge). The decision of which gauge to choose is largely a func- The majority of exposures healthcare workers, including Para- tion of two factors. The fi rst factor is the viscosity of the fl uid. medics, experience to blood-borne pathogens are the result of The thicker the fl uid to be injected or withdrawn through the accidental puncture of the skin with a hollow-bore needle. needle, the larger the needle that will have to be used. The United States Centers for Disease Control and Preven- tion estimates that over 600,000 needlesticks will occur annu- ally. Many of them are preventable. Infection control expert Kathrine West, RN, estimates that each needlestick injury Street Smart will cost employers approximately $1,200 in emergency care, lost hours and wages, and medical follow-up for a case with Paramedics seldom use less than an 18 gauge needle a non-infectious exposure.43 when drawing blood, either through an intravenous In response to this occupational hazard, the U.S. Con- gress strengthened the Occupational Safety and Health catheter or via direct needle insertion. Smaller Administration (OSHA) blood-borne pathogens rule, enacted catheters tend to break the red blood cells apart in 1991, with the Needlestick Safety and Prevention Act of in the turbulence, called lysing of the red blood 2000, effective the April 18, 2001. The Needlestick Safety cells. Lysed red blood cells spill the cell’s contents, and Prevention Act requires wider use of engineering con- trols which can prevent needlestick injury.44 Examples of including potassium, into the plasma. The result is engineering controls which can help prevent needlestick false plasma values obtained from the laboratory. injury include retractable needles, needles that are withdrawn into the syringe barrel by a spring-action mechanism, self- sheathing needles, needles that have a retractable hard case The other factor in needle selection is the speed of deliv- that is advanced over the needle as the needle is withdrawn, ery. A smaller diameter needle creates greater resistance to and hooded needles that have a protective covering over fl ow (i.e., friction loss) and requires higher pressures to push the needle. Principles of Medication Administration 535 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Manufacturers, in an effort to eliminate the needle entirely, have created needleless medication systems which use non-needle connections at the medication ports. They also have created jet injection systems that use high-pressure air to open the skin temporarily while medicine is deposited beneath the skin. However, there are still circumstances in which a needle will be used. Therefore, the Paramedic must be familiar with its use. Every Paramedic is responsible for safely disposing of used/contaminated needles into a safe sharps container. The sharps container should be close at hand, within arm’s reach, and be easy to access. Under no circumstances should a nee- dle be bent or cut. Cutting a needle can create a microspray of drug and/or blood in the air, which can be inhaled or settle into the eyes. Figure 26-5 Preparing a prefi lled medication Medication Containers syringe. Medications are packaged in either vials or ampoules. The Paramedic must withdraw the drug from its container, into a needle and syringe, before use. Ampoules, a single-use, single-patient drug container, is manufactured alone or as a part of an ampoule with syringe delivery system, sometimes called a “preloaded ampoule.” In the emergency setting, where time is of the essence, these prefi lled ampoule/syringe systems are commonplace. They are generally fi lled with the amount of drug needed to treat a 70-kg patient. When using one of these ampoule systems, the Bristo- jet®, the Paramedic removes the two end caps which pro- tect the ampoule and the syringe. With the caps removed, the Paramedic would mate the two pieces, twisting them together so that a recessed needle within the syringe portion would penetrate the stopper. When this step is completed, the Paramedic would discard any extra drug and air which may be contained within the ampoule and proceed to intro- duce the syringe’s preset needle |
into the medication port of the administration set or to inject the drug into the patient (Figure 26-5). The Paramedic should use caution when discarding excess drug so as to avoid accidental injury. Drugs, carelessly discarded into the air, can splash onto the ambulance ceiling and fall back into the eyes of unsuspecting occupants in the patient compartment, including the patient. Some ampoules still have to be broken before the medi- cation can be withdrawn (Figure 26-6). The Paramedic should fi rst shake the medicine down out of the ampoule’s neck and into its body. Once accomplished, the Paramedic would then place the ampoule on a fl at fi rm surface and grasp Figure 26-6 Safely break the glass stem of the ampoule’s body with the thumb and forefi nger of the the ampoule before inverting the ampoule and nondominant hand. Using either a commercially available withdrawing the medication. ampoule breaker (which is preferred) or a 2-inch gauze pad, the Paramedic would grasp the ampoule’s head and, while holding it in a direction away from him, smartly snap the Paramedic would introduce the syringe, with a glass-fi ltering ampoule’s neck. The Paramedic should avoid the sharp shards needle, into the medication just below the meniscus. of glass from fl ying into the eye. The Paramedic is advised to In some cases, the Paramedic may elect to invert the wear protective eyewear, as splinters of glass can fl y from ampoule and withdraw the medication. The medication will the ampoule into the eye. Having accessed the ampoule, the remain in the ampoule, provided the needle does not touch 536 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. the walls of the ampoule and break the liquid surface tension. However, most Paramedics, particularly when in the back of a moving ambulance, prefer to keep the ampoule on a fi rm surface with the bottom down in order to aspirate the drug into the syringe. When the medication has been withdrawn, and the ampoule is useless, then the glass ampoule should be discarded like any other sharp, into an approved sharps container. Vials are intended for multiple use and therefore are more likely to become contaminated. Some EMS organiza- tions and healthcare institutions require that the vial’s con- tents be used within a specifi c period of time (e.g., 24 hours) and then discarded in order to avoid possible contamination. Many Paramedics discard vials after use and do not use vials on multiple patients. Figure 26-7 Withdrawal of medication from a The risk of contamination is higher when a Paramedic vial. is in the high-pressured, time-limited environment of an emergency. Innocent errors in medical asepsis are frequent enough that single-patient ampoules, and individually pack- the nondominant hand, the needle is then withdrawn quickly aged patient supplies, are routinely used by Paramedics to (Figure 26-7). avoid these problems. Inserting a needle into a dime-sized stopper held over the When a vial is used, the Paramedic should fi rst remove Paramedic’s head, especially while in a moving ambulance, is the plastic cover, then take a moment and clean the stopper dangerous and places the Paramedic at risk for a needlestick with an alcohol-soaked pad or gauze, commonly called a prep injury. pad, to remove gross surface contaminants. On occasion, air bubbles will inadvertently arise, typi- After calculating the proper volume for the dose, based cally if the medication is withdrawn too fast. If the air bub- on the drug’s concentration, the Paramedic would then draw bles are visible in the barrel of the syringe, a smart tap with up an equal volume of air. Vials are a closed system, and the forefi nger will generally dislodge them, allowing them to withdrawing a volume from the vial without replacing it with rise to the top of the syringe. The air can then be expressed an equal volume would create a vacuum, one that could draw from the syringe. in any surface contamination. Furthermore, the Paramedic will encounter diffi culty withdrawing the medication if the pressures are not equalized. Therefore, it is essential that the Street Smart Paramedic fi rst inject air, in equal volume, into the vial before withdrawing the medicine. Some Paramedics use a large-bore “mixing” needle Conversely, overpressurizing the vial, with additional volume of injected air from the syringe may make the drug to draw the medication up quickly from a vial, then withdrawal quicker and easier. However, as the needle is replace it with the smaller needle used for injection. withdrawn a fi ne mist of medicine will escape into the air. This helps decrease potential contamination as Some commonly used medications which are packaged in well as speeding up the process of medication a multidose vial (e.g., epinephrine) can be very caustic to the Paramedic’s unprotected eyes when aerosolized in this administration. fashion. To withdraw medicine from the vial, the vial should be placed on a fi rm fl at surface and held in place by the thumb Routes of Injection and forefi nger of the nondominant hand. As the Paramedic Hypothetically, the best means to get a drug directly into a introduces the needle into the vial’s stopper, the bevel should target organ is to inject the organ directly. Intrathecal (within be facing upward and a slight downward pressure exerted. the spinal column), intrapleural (between the lung’s pleura), The downward pressure will ensure that the needle’s bevel intra-articular (within a joint), and intracardiac (within the slices the stopper and does not core it. With the needle in heart) injections are just some examples of medication injec- place, visible just beyond the stopper, the Paramedic would tions into target organs. invert the vial, inject the premeasured volume of air into the With the exception of intracardiac injections performed vial, and then withdraw the medicine from the vial. by early Paramedics before the advent of current intravenous Once the syringe is fi lled, the Paramedic would then techniques, Paramedics generally have injected drugs into the invert the vial again and place it back onto the fl at surface. peripheral circulation and depended on the circulatory system With the vial stabilized between the thumb and forefi nger of to get the medication to the target organ. Even drugs injected Principles of Medication Administration 537 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. into the endotracheal tube depend on absorption from the With the needle in place, the Paramedic would gently alveolar capillary beds. aspirate to ensure that the needle was not inadvertently placed The greatest drawback of indirect parenteral injection may into a vein. If a blood fl ash is witnessed, then the needle should be its dependence on adequate circulation to reach the target immediately be withdrawn, the medication pulled back into organ. In many cases, the patient presents to the Paramedic the syringe, and new equipment prepared. The bloody medi- with inadequate circulation (these patients are hypoperfused). cation solution should not be injected. Instead, a new dose of Subsequently, insuffi cient quantities of drug get to the target medication should be drawn up in a new syringe. organs when injected via an indirect parenteral route. Intradermal Injection Preparation for Parenteral Injection Paramedics perform intradermal injections under a limited set of circumstances. Intradermal injection is used when pre- As in all procedures performed, the Paramedic would iden- paring an intravenous site with a local anesthetic. Intradermal tify the patient, introduce oneself, inquire about the patient’s injection is also used for tuberculosis testing. The objective allergies, advise the patient about the procedure’s intended of an intradermal injection is to place a small quantity of effects, and then explain what reasonable and foreseeable medicine just under the epidermis and in close proximity of risks could be experienced. the subcutaneous tissue. Because the space within the skin After obtaining informed consent, the Paramedic should is very small, no more than 0.5 mL should be injected into practice medical asepsis, starting with hand washing with one site. soap and water or an acceptable hand sanitizer and then don The tools that the Paramedic needs to assemble for an gloves. Generally, non-sterile gloves are adequate for the intradermal injection include a 1 mL syringe and a short nee- tasks at hand. dle about 3/8 inch to 1/2 inch that is either 26 or 27 gauge. Success in many of these injection techniques can be Sites for intradermal injection include the anterior forearm, improved if the Paramedic takes the time to fi rst position the the upper chest, and the posterior shoulders. After drawing up patient. With the patient resting comfortably, the Paramedic a small quantity of the medication (typically 0.01 to 0.1 mL), would proceed by selecting a site, chosen in accordance the patient is prepared as previously described. with commonly accepted sites used for that particular injec- Grasping the syringe as one would a sewing needle, the tion technique. When assessing the various sites for injec- Paramedic would place the needle gently on the surface of tion, before choosing one, care should be taken to ensure that the skin, with the needle at a 15-degree angle, and advance the selected site is not hard, swollen, or tender and is free of the needle under the skin. With the length of the needle rashes, moles, birthmarks, burns, scars, or broken skin. under the skin, a small 1 cm blister is created by injecting the After identifying the intended injection site, the Paramedic medication. This blister, called a bleb, is about the size of a would place an isopropyl-soaked pad on the site and, working mosquito bite. The needle should remain visible just under outward in ever-expanding circles, prepare an area approxi- the skin the entire time. mately twice the length of the needle. The purpose of the alco- When the task is completed, the needle is withdrawn in hol bath is to remove any gross contaminates from the skin’s the same direction as it was advanced and immediately placed surface as well as oils that would prevent the bandage from in a sharps container. If capillary bleeding is evident, then an adhering to the skin. The alcohol bath itself does not render the adhesive bandage can be placed loosely over the site. skin sterile, just clean. Incidental surface contamination (bac- teria and the like), which may be dragged into the wound cre- ated by the injection is dealt with by the body’s defenses. Capillary Blood Draw Iodine-based solutions, such as Betadine®, are generally Paramedics are increasingly requested to perform capillary not used because iodine seeping into the stab wound created by blood sampling in the fi eld. The capillary blood can then the injection can be irritating. It may also delay new cell growth be used for blood glucose analysis or fi eld Troponin levels. and damage sensitive tissues in the vicinity of the injection. These point of care blood tests enhance the Paramedic’s abil- With the patient prepared and the area prepped, the Para- ity to provide immediate emergency services while still in the medic would then pick up the prefi lled syringe in the domi- fi eld and to transmit critical information to the emergency nant hand and remove the needle guard. The Paramedic must department. then stabilize the skin with the nondominant hand. With the The most common capillary blood draw is the fi n- needle and syringe fi rmly in hand, the Paramedic would then ger stick. However, a heel stick may be preferred for small proceed to fi rmly, and with authority, insert the needle under infants or children. With the limb in the dependent |
position, the skin. Studies have shown that the speed of insertion does encouraging peripheral vascular congestion, the Paramedic not decrease the pain which the patient may experience.45 would proceed with the routine battery of questions in order However, hesitation on the Paramedic’s part is telegraphed to obtain consent. to the patient, which may cause the patient’s anxiety may Once consent is given, the side of the fi nger tip proximal increase. Patient anxiety has been shown to have a positive to the pad of the fi nger tip is cleansed with an alcohol prep correlation to the perception of pain. pad (wipe). While the alcohol is drying, the lancet is picked 538 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. A complication of frequent subcutaneous injections at one site, such as may occur with repeated insulin injections, is tissue fi brosis. Tissue fi brosis occurs when phagocytes infi ltrate the area and attempt to remove the irritating foreign matter (the medication) and create a sterile abscess. Drugs injected into fi brotic tissues cannot be absorbed readily and will adversely affect the patient’s response to the medication. Generally, a 1 mL to 3 mL syringe is used for subcuta- neous injections. The syringe is tipped with a 1/2-inch 26 to 30 gauge needle. With the syringe loaded with no more than 1.5 mL of medication for one injection and held in the domi- nant hand, the Paramedic would gently grasp the skin around the site with the nondominant hand. With the skin tented approximately 1 inch between the fi ngers, the Paramedic Figure 26-8 Capillary blood draw. would insert the needle into the skin at a 45-degree angle. If the skin is tented approximately 2 inches, then it is acceptable to insert the needle at a 90-degree angle. Once the needle is up by the dominant hand and prepared. In some cases, a pro- inserted into the skin, the Paramedic would gently aspirate tective cover must be removed from the lancet. In other cases, for blood and then inject into the subcutaneous pocket which the lancet is spring-loaded and retracts back into a protective has been created by pinching the skin. sheath. In those cases, the lancet may have to be activated (armed) before use. Intramuscular Injections Grasping the patient’s fi nger with the gloved nondomi- nant hand, the Paramedic would place the lancet over the Intramuscular injection is a common method of medication site and either pierce the skin in a quick darting motion or administration. Once the drug is deposited between the lay- depress the actuator of the spring-loaded lancet. Once the ers of the muscle, and below the subcutaneous tissue, it can skin is pierced, it should bleed freely. In some cases, it may be escape into the surrounding capillary beds within the muscles necessary to gently milk the tip of the fi nger to get a hanging and provide rapid systemic action. Intramuscular injection is drop of blood. Vigorous or forceful pressure on the tip of the frequently used for the uncooperative patient who is in need fi nger may damage local tissue. It might also introduce new of sedation/chemical restraint to prevent harm to himself or fl uids into the sample, possibly causing any subsequent blood others. Antipsychotic agents, such as haloperidol, can be test results to be invalid. given in this manner during a psychiatric or behavioral emer- After immediately disposing of the lancet in an approved gency. However, not all medications should, or can, be given sharps container, the Paramedic would collect the droplet via intramuscular injection. Digoxin, diazepam, and pheny- sample and then apply a gauze pad or self-adhesive bandage toin are just some of the medications that are poorly absorbed to the fi ngertip. The patient should be encouraged to elevate via intramuscular injection. the arm above the heart (Figure 26-8). Intramuscular injection has an advantage over intra- venous injection in the elderly and immunocompromised patient. Intravenous injection bypasses the majority of the Subcutaneous Injections body’s defenses against infection, whereas intramuscular Subcutaneous injection of medication is the slowest and least injection preserves several of those defenses. dependable means of obtaining therapeutic drug levels in the Intramuscular injections depend on adequate periph- bloodstream. Local conditions in the skin, such as capillary eral circulation. Intramuscular injections, and intramuscular perfusion and adipose tissue, combine to make drug absorp- injections in certain sites, may be contraindicated in patients tion slower and more erratic than intravenous injection.46-48 with peripheral vascular disease and disease states which cre- Yet for some medications, such as heparin and insulin, the ate Hypoperfusion (e.g., anaphylactic shock). Intramuscular subcutaneous route is acceptable. injections also create trauma during the injection, creating a After providing the appropriate information and obtain- puncture wound. Some patients with coagulation disorders, ing consent, an acceptable site is prepared. A variety of sites such as the patient with hemophilia or one who is status-post are acceptable for subcutaneous injections including the fi brinolysis, may experience signifi cant bleeding (a hema- abdomen, the lateral aspects of the upper arm, and the ante- toma) at the injection site. rior thigh, as well as the ventrodorsal gluteal area. Studies The slow distribution of intramuscular medications makes have shown that the subcutaneously injected medication is intramuscular injection a preferred route for so-called depot absorbed quickest from the abdomen, followed by the upper medications. Depot medications are medications deposited arm and then the anterior thigh. There is no data comparing under the skin which produce sustained therapeutic levels the gluteal injections to the other sites. over a longer period of time. Principles of Medication Administration 539 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. The intramuscular needle range is between 18 to 24 gauge Greater Vastus Injection and the selection of the length of the needle is more impor- trochanter lateralis site tant than the gauge. If the patient is less than 110 pounds (50 kg), a 1-inch needle will generally reach the muscle below the skin. If the patient weighs between 110 and 220 pounds (50 to 100 kg), then a ½- to 2-inch needle is appropriate. For patients over 220 pounds, a needle longer than 2 inches may be needed. In the case of the morbidly obese patient, it may be necessary to use a 4-inch needle.49 It is important that Femoral Rectus Lateral artery femoris femoral the Paramedic carefully assess the injection site. Variations condyle in muscle development can alter the Paramedic’s decision regarding needle length. Figure 26-10 Vastus lateralis injection site. Because of the barrel’s diameter, a 3 mL syringe is gen- erally used for intramuscular injections as it provides better control. However, the syringe chosen is dependent on the vol- ume to be administered per injection which is, in turn, depen- dent upon the site selected. After the patient has consented and is properly prepared, Acromion the site is selected. There are four common intramuscular process injection sites to choose from, and each site has specifi c Clavicle advantages over the other sites. Scapula Deltoid The fi rst site, the ventrogluteal (VG), is located on the muscle Humerus lateral thigh proximal to the hip.50–52 The muscles underly- Axilla ing the VG are the gluteus medius and the gluteus minimus. Radial nerve What may be more important is that no large veins, arteries, Deep brachial or nerves underlie the area. Beyea and Nicoll reported that artery the ventrogluteal site had the lowest risk of nerve damage, muscle spasm, gangrene, and pain of any of the other injec- Figure 26-11 Deltoid injection site. tion sites. To locate the site, the patient is placed in a side-lying position (lateral recumbent). The Paramedic would then pal- up the medication in the syringe and prepares the patient for pate the bony prominence where the femur inserts into the the injection. Up to 2 mL of medication can be injected in pelvis. Placing the palm of the hand over the insertion, the the vastus lateralis without causing the patient signifi cant Paramedic would grasp the anterior superior iliac crest with discomfort. the fi ngers. The injection site is between the fi rst fi nger and Paramedics generally prefer to use the deltoid muscle the thumb (Figure 26-9). (Figure 26-11) because it requires less patient exposure and An alternative intramuscular injection site is the vastus is easier to access. The deltoid muscle overlays the shoulder lateralis (VL) (Figure 26-10). After positioning the patient and extends downward toward the elbow, forming an inverted in the supine or semi-Fowler’s position, the anterior thigh is triangle in the process. With the patient in high-Fowler’s posi- exposed. The Paramedic mentally divides the vastus lateralis tion, the Paramedic would instruct the patient to bend the arm muscle into three equal portions. Choosing the middle sec- at the elbow, thus relaxing the deltoid muscle. The Paramedic tion of the VL, the Paramedic prepares the intended injection would then palpate the bony prominence where the humerus site with an alcohol-soaked pad. Next, the Paramedic draws inserts into the shoulder. Locating the humerus, the Paramedic would measure approximately three fi nger-breadths down to Anterosuperior Greater the middle, or belly, of the deltoid muscle and prepare the site iliac spine trochanter with an alcohol-soaked pad. Approximately 1 mL of medica- tion can be given into each deltoid. The deltoid site should not be used for children who lack the muscle development in the shoulders appropriate for the injection. The most common intramuscular injection site is the dor- sogluteal (DG) (Figure 26-12). A large muscle, the gluteus medius, underlies the injection site and provides an excellent location for a depot of medicine. The patient is typically in Injection site the prone position (an uncommon position for patients to be transported by EMS) and then the patient’s buttocks exposed. Figure 26-9 Ventrogluteal injection site. Alternatively, the patient can be placed in the side-lying 540 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Injection Iliac crest disk or a cream that is applied to the intended injection site site and left in place for a minimum of 60 minutes. Following Posterosuperior removal of the dollop of cream, or the patch, the skin should iliac spine be anesthetized.53,54 While EMLA cream may not be con- Superior venient for use in the fi eld, it should be considered in cases gluteal artery where repeated injections of medicine may be needed. Gluteus and vein Alternatively, fl uori-methane has great potential for maximus muscle use in the fi eld.55–57 Fluori-methane, a topical refrigerant, numbs the skin at the injection site in as little as 15 seconds. Fluori-methane, also referred to as a vapocoolant spray, can be either applied directly to the skin, though some patients Figure 26-12 Dorsogluteal injection site. complain of transient sharp discomfort, or onto a cotton ball for topical application. One study suggested that a vapocool- ant spray was equally as effective as EMLA cream. Another position, or lateral recumbent position, and only the upper study indicated that placing ice alone on the skin, for 30 sec- portion of the buttocks and the patient’s fl ank is exposed. It onds, was not effective in reducing pain during injection. should be noted that the gluteus is not synonymous |
with the The next potential source of injection pain is the trauma buttock. The gluteus is located proximal to the inferior por- created by the needle’s insertion. One study suggests that the tion of the patient’s fl ank. biomechanics of injection (i.e., proper injection technique) As the gluteus medius is relatively large, compared to is important to the patient’s comfort.58–61 A needle held and the muscles underlying the other injection sites, use of the inserted in a linear manner, perpendicular to the plane of the DG site is advantageous during a restraint situation. In those skin, reduces the “path width” compared to the path width situations where the patient needs sedation and/or chemical seen with a curved (arcing) needle path. Tissue shearing is restraint for a behavioral emergency, the DG offers a large minimized and therefore patient discomfort lessened. “target” and thus a greater chance of success. After the patient Finally, there is the matter of the medication deposited has been given sedatives, he should be placed in the supine, within the muscle. This discomfort is, in large part, due to the face-up position as soon as possible in order to monitor respi- leakage of the caustic and irritating drugs into the pain recep- rations and avoid positional asphyxia. tors of the subcutaneous tissues. The deeper muscle layers To ascertain the location of the DG injection site, the are relatively free of pain receptors. The application of a few entire one buttock is mentally divided into four quadrants. easy to perform techniques which “lock” the drugs into the The uppermost and outermost quadrant, proximate to the muscle will decrease the patient’s discomfort and improve the iliac crest, is prepared. Great care should be taken estimating Paramedic’s confi dence with injection skills. the injection site as the sciatic nerve transverses two of the Two techniques have been developed by nurses to other three quadrants. Unintended injection into the sciatic decrease this leakage and the accompanying discomfort. nerve can lead to paresthesia, paralysis, and permanent nerve Both techniques involve careful attention to the particulars damage. Alternatively, the Paramedic can draw an imaginary of the injection technique. The fi rst technique, the airlock, is line from the height of the iliac crest to the insertion of the performed while preparing the drug in the syringe for injec- femur and choose the midpoint of that line. tion. The second technique, the Z-track, involves manipula- Generally, the DG injection site is reserved for adults. tion of the injection site during the injection. Children must be walking before a DG injection site should The airlock technique has the Paramedic injecting a small be considered. In the adult patient, a maximum of 5 mL can bubble of air into the injection, essentially sealing off the drug be injected into each DG site. However, the Paramedic should below from leaking out to the subcutaneous tissues above. To consider splitting the dose and doubling the sites for injection create an airlock, the Paramedic fi lls the syringe with the medi- to increase patient comfort. cation as usual. With the syringe clear of the ampoule, the Para- medic would then withdraw the plunger further, clearing the Painless Injections drug from the needle and entraining about 0.1 mL of air into the Patients complain, sometimes bitterly, about the discomfort syringe. It is important that the Paramedic verify that the correct which can accompany an intramuscular injection. This dis- volume of drug remains in the syringe (Figure 26-13). comfort can be related to the needle puncture and the tear- Quickly inverting the syringe should cause an air ing/shearing of the dermis and muscle as the needle passes bubble to be created at the apex of the plunger. With the air through the tissue layers, as well as the presence of the medi- bubble in place, the Paramedic would proceed to the injec- cation within the tissue. tion. For the airlock technique to work, it is essential that the Several products are available that help to reduce the syringe remain at an upright 90-degree plane from the injec- pain of needle insertion. The fi rst, a eutectic mixture of local tion surface. This ensures that the air bubble is injected at anesthetics (EMLA), is a cream of lidocaine 2.5% and prilo- the end of the injection. The ventrogluteal (VG) site and the caine 2.5%. EMLA is available as a self-adhesive anesthetic dorsal gluteal (DG) site are conducive to this technique. Principles of Medication Administration 541 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Skin pulled taut Skin released Figure 26-14 Z-track injection technique. Injection Site Massage Some controversy surrounds the common practice of mas- saging the area surrounding the injection site immediately after the injection. In some cases, it is acceptable to gently massage the area surrounding the injection. Gentle pressure applied to the area dissipates the impact of the sharp pain receptors through competition with various pain fi bers. How- ever, some medications are caustic to the muscle tissue. With these medications, massaging the area distributes the medi- cation over a larger area, creating more discomfort for the patient. The Paramedic should be knowledgeable about the med- Figure 26-13 Airlock technique. ication before just routinely proceeding with massaging all injection sites. For example, it is acceptable to massage the Another technique that can help prevent drug leakage site following an injection of morphine sulfate in order to into the subcutaneous tissue is the Z-track technique. The decrease the patient’s discomfort, but massaging the site after Z-track technique creates an offset injection pathway, using an injection of diazepam would only serve to increase the subcutaneous tissue to block leakage.62 patient’s discomfort. To create a Z-track, the Paramedic with the drug-fi lled Also at issue with the routine practice of massaging an syringe in the dominant hand, bevel up, would pull gentle injection site is its impact on absorption. While intramuscu- traction on the injection site with the nondominant hand. Fre- lar injection of insulin is uncommon, its rate of absorption quently, Paramedics will grasp the upper arm, if the deltoid is quicker via intramuscular injection than subcutaneous is used, and pull traction with the thumb of the nondominant injection. This quality makes intramuscularly injected insu- hand. With a smart fl ick of the wrist, as if one was throwing lin attractive during a diabetic emergency. However, massage a dart, the needle is inserted into the skin. After aspiration of the injection site can dissipate the insulin even further, confi rms proper placement, the drug is injected in a delib- making its uptake more rapid and creating a risk of unan- erate fashion. Injecting the drug too quickly can create dis- ticipated hypoglycemia. If the Paramedic is unsure if mas- comfort as stretch receptors are stimulated by the presence of saging the injection site is acceptable, then the maxim of “do the space-occupying depot of medicine. Alternatively, inject- no harm” should be followed and the injection site should not ing, or “pushing,” the drug too slowly can cause increased be massaged. patient apprehension. Practice establishes the best rate of administration. Special Populations The next actions taken by the Paramedic are critical to The two extremes of age—elderly and children—each present the success of the Z-track technique (Figure 26-14). Before a special challenge for the Paramedic who must perform an the needle is withdrawn from the skin, the Paramedic must injection. Both the patient and the provider alike are anxious release the traction on the skin. Thus, when the needle is during a pediatric injection. To develop strategies to improve completely withdrawn the skin overlying the muscle will slide success, the Paramedic must take into account the child’s over the medication depot, closing it off to the surface. developmental stage and adjust the approach accordingly. 542 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. In many cases, the infant is unaware of the events sur- mass, limiting available injection sites. These emaciated rounding him or her, but is acutely aware of the discomfort patients, with less muscle mass and loss of the capillary beds, that follows. In those cases, it may be acceptable to have the tend to absorb medications less readily. infant held in the mother’s arms to be comforted after the procedure. The greatest challenge may be the toddler. The toddler is keenly aware of his or her environment, is able to com- Street Smart prehend the situation, and receives a great deal of emotional feedback from parents as well as caregivers. Typically, a tod- Uninformed Paramedics mistakenly think it is dler must be temporarily restrained during the injection. One technique is to place the toddler on the parent’s lap, chest to preferable to inject medications below the level chest, with the parent’s arms entrapping the child. The tod- of injury of a paraplegia patient, eliminating the dler’s legs would then be aside and behind the parent. The pain which can accompany an injection. The drug Paramedic would approach the parent from behind, grasp the absorption below the level of the spinal injury is outstretched leg, and perform the injection. The elderly patient presents a challenge of another kind. erratic and unpredictable. The combination of age and poor nutrition reduces muscle Principles of Medication Administration 543 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. The large number of medication administration routes and techniques represent a substantial portion of the universe of skills that a Paramedic must master. Each medication route has its advantages and its drawbacks, its indications and its contraindications. It is the Paramedic’s responsibility to ensure that the patient’s medication needs and the preferred medication route are compatible. Key Points: • It is a Paramedic’s responsibility to choose the in pounds, in half, then subtract 10% off from the right drug and the right dose for the patient, and to result for an approximate weight. administer it by the right route at the right time in order to achieve the optimal therapeutic effect. • A drug concentration is described as the amount of drug in 1 milliliter (mL) of a solution. • Forms of medication can be grossly categorized into liquids, solids, and injectable liquids. • Some prehospital medications must be mixed just before use to ensure maximum effectiveness. • Injectable forms of medication come in either ampoules or vials. Vials are essentially resealable • A standard drug order states the amount of the drug, the name of the drug, and the route that is to ampoules and may be used for multiple patients. be administered. • The apothecary system of measurements includes units of grain (gr) and is rarely used today by • When an adult dose must be adjusted to a pediatric dose, and the pediatric dosing is not available, then physicians. the child’s total body surface area (BSA) is divided • The common household system or United States against the total body surface area of an adult— customary system contains such units as the ounce approximately 1.73 meters squared for a 6-foot and the teaspoon and remains the predominant tall, 150-pound adult. The resulting percentage is system of measurement in the United States and then taken from the adult dose and is roughly equal Canada. to the pediatric dose. |
• The metric system is based in units of 10. • Intravenous fl uids may be infused at a “wide open” rate to administer a large volume of fl uid quickly, • Insulin and penicillin are examples of medications at a prescribed rate per hour or minute, or at a that are measured in international units (IU). KVO rate of 50 mL per hour to keep the catheter This unit represents the relative strength of the patent. substance after it has been tested on an organism. • Methods for determining an intravenous drug • Conversions of metric measurements are based on infusion rate include the formula method and the a factor of 10. All multiplications above 1 gram clock method. are noted in the Greek prefi xes kilo-, hecto-, and deca-, whereas all divisions of a gram are noted by • Weight-dependent intravenous drug infusions the Latin prefi xes deci-, centi-, milli-, and micro-. include the patient’s weight in the standard drug infusion calculation. • The most accurate method of converting a patient’s weight from pounds to kilograms is • To convert Fahrenheit to Celsius (medical standard dividing the patient’s weight in pounds by 2.26 and temperature measurement), the EMS provider obtaining the weight in kilograms. However, the subtracts 32 from the Fahrenheit result and then Paramedic may also divide the patient’s weight, multiplies by 5/9. 544 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. • Paramedics practice the fi ve rights of medication • The vast majority of self-administered medications administration. are swallowed. The solid pill, capsule, or liquid is • then absorbed in the gastrointestinal tract, where After being given any drug, the patient is re- it is passed (via the portal circulation) through evaluated to see if the drug was effective. This the liver and on into the central circulation. From re-evaluation, and subsequent documentation of an EMS perspective, the patient must be able to patient response to medication, is so important that maintain the airway independently and swallow the some Paramedics refer to it as the sixth right, the medication. right documentation. • • Gastric tubes can be placed to instill feedings The initials DARE, a simple mnemonic, can as well as medications in the form of liquids or help Paramedics remember the elements of suspensions. Most Paramedics insert an orogastric documentation for every medication administration. tube in order to evacuate or decompress the • The Paramedic can use the mnemonic AIR to obtain stomach. Use of a special gastric tube, called a an informed consent from a competent patient. Sengstaken-Blakemore tube, permits the Paramedic to apply direct pressure inside the stomach or • Local routes of medication administration are esophagus to the source of bleeding. intended to target a specifi c organ or function. Optic medications are applied directly to the eye, • Intermittent suction or the placement of a dual- and otic medications are applied to the ear. lumen gastric tube helps prevent a gastric tube from adhering to the gastric mucosa, leading • The inner mucosa of the nostrils has a rich capillary to local irritation and bleeding. After the bed that is an excellent route for the administration placement of a gastric tube, the patient should be of systemic medications. Local nasal medications monitored for signs of hypoxia, such as premature can be applied via an atomizer into the intended ventricular contractions (PVC), and altered nostril, propelling the medicine against the mucosa. level of responsiveness. If the gastric tube is Like the nose, the mouth has a capillary-rich obstructed, the Paramedic can irrigate the tube mucosa that will rapidly absorb any medicine and with saline or sterile water instilled into the tube distribute it systemically. via syringe. • Though not widely used, local topical medications may • Drugs that are absorbed from the rectum avoid include the application of a topical antibiotic at the inactivation by stomach acids and intestinal insertion site of an intravenous catheter. Other local enzymes. Around 50% of the absorbed drug bypasses medications can be douches (solutions introduced the portal circulation, minimizing the impacts of into the vagina via an apparatus) or enemas (solutions fi rst pass metabolism and biotransformation. To introduced into the anus via an apparatus). administer the medication, the patient is placed in a modifi ed left lateral position, called the • The enteral route of systemic drug administration Sim’s position. The rectal administration route is refers to medications given via the gastrointestinal useful when the patient is unable to accept oral tract (e.g., oral medications). Parenteral routes of medications, such as in the case of persistent medication administration include inhalation and vomiting or continuous seizures in children. injection. • When a rapid onset of drug action is required • The sublingual route is an enteral route whereby (e.g., during an emergency), the parenteral route medication, in a liquid or solid form, is placed offers the most direct route to the target organs, in the space inferior to the tongue, where it is sidestepping the gastrointestinal system (enteral rapidly absorbed. The distinct advantage to the administration) and delivering drugs directly to sublingual route is that it bypasses the liver and the central circulation. Advantages of these routes thus avoids hepatic fi rst pass metabolism. Using the include circumventing the GI absorption process, buccal route, or cheek, is similar to administering maintaining more predictable serum drug levels, medications sublingually. Principles of Medication Administration 545 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. and using them with patients who are uncooperative the medication depends on the patient’s inspiratory or incapable of cooperation (e.g., unconscious). effort. • Intranasal administration takes advantage of • By suspending the medication in a stream of air, the the nasal passages. They are lined with very small volume nebulizer (SVN) is thought to produce vascular mucous membranes that can absorb a better particle size for inhalation (about 1 to medications quickly and without the risk of fi rst 3 microns). Prior to using an SVN, the Paramedic pass metabolism associated with enteral routes of should conduct a history to determine the patient’s drug administration. The intranasal route works responsiveness to MDI bronchodilators. He should well with patients with altered mental status also perform a physical, auscultating for wheezes or combativeness, and/or when the Paramedic or absent breath sounds. Key to assessing the is in a moving ambulance. Several drugs can be effectiveness of any SVN treatment is the patient’s administered intranasally. The clear advantage of subjective judgment regarding her own dyspnea. For intranasal administration of drugs is the decreased intubated patients, a SVN may be attached in-line risk of accidental needle injury. with the bag-valve-mask assembly. • Naxolone is a drug used for suspected opioid • Topical medication absorption into the overdoses. The use of naxolone intranasally is subcutaneous capillary beds, or transdermal considered “off-label use,” meaning the FDA has medicine, offers a drug administration route not approved the drug for use in this manner. The that can have sustained systemic delivery of a volume administered intranasally should be no medication. Medications given via a transdermal more than 1 mL of liquid, and the drug should be patch can include nicotine, hormone replacement, atomized to a particle size of between 10 mcg and opiate analgesics, and nitroglycerine. 50 mcg, the optimal particle size for absorption. • The components of a hypodermic syringe include • The inhalation of medications is the inhalation of the syringe and the needle, often connected via a drug-laden vapors into the bloodstream via the luer lock or slip-tip adaptor. Syringes are labeled respiratory route. Pulmonary treatments focus on according to the volume within the barrel (e.g., the delivery of respiratory agents directly into the 1, 3, 5 mL) and the calibrations on the side of the pulmonary tree. The common drawback to both barrel. The exception is insulin syringes, which are these methods is the dependence on the patient’s labeled in international units (IU). Surface tension respiratory function. and adhesion of water to the walls of the syringe • form a meniscus. The volume of the drug in the As air enters the lungs, it meets resistance as syringe is determined by comparing the bottom of the structures narrow. The resistance slows the the meniscus with the calibration on the barrel. air down; by the time it reaches the alveoli, it is nearly still. This encourages fallout, as large • The needle is the second component of the particles carried in the air settle out as the velocity hypodermic syringe. Measured in gauges, the is lost. The result is that nearly particulate-free smaller the number means the larger the diameter air enters the alveoli. This works against large of the needle (e.g., 14 gauge > 20 gauge). The droplets of aerosolized medications and reduces the Paramedic should choose a needle size dependent effectiveness of many respiratory drugs. on the viscosity of the fl uid and speed of delivery. • Injecting a drug into a medication port of an The metered dose inhaler (MDI) is a portable and intravenous set, or performing an intramuscular, well-accepted respiratory treatment platform. subcutaneous, or intradermal injection, all require a However, it is relatively ineffective, depositing specifi c size and length needle. less than 20% of the medication in the distal lung fi elds. A spacer device can be used to increase • Retractable needles, self-sheathing needles, MDI’s effectiveness. Dry powder inhalers (DPI) use a needles that have a retractable hard case that pulverized solid drug for inhalation with a delivery is advanced over the needle as the needle is device similar to an MDI. Again, the effectiveness of withdrawn, and hooded needles that have a 546 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. protective covering over the needle are all efforts • Subcutaneous injection of medication is the made through engineering controls to help prevent slowest and least dependable means of obtaining needlestick injury. therapeutic drug levels in the bloodstream. • Acceptable sites for subcutaneous injections It is every Paramedic’s responsibility to safely including the abdomen, the lateral aspects of the dispose of used/contaminated needles into a safe upper arm, and the anterior thigh, as well as the sharps container. The sharps container should be ventrodorsal gluteal area. Frequent subcutaneous close at hand, within arm’s reach, and be easy to injections at one site, such as may occur with access. repeated insulin injections, result in tissue fi brosis. • Medications are packaged in either vials or • Intramuscular injection deposits the drug ampoules. There are prefi lled ampoules/syringe between the layers of the muscle, and below the systems as well as glass ampoules that have to be subcutaneous tissue, providing rapid systemic broken before the medication can be withdrawn. action. Intramuscular injections are contraindicated When withdrawing air from a vial, it is essential that in patients with peripheral vascular disease and the Paramedic fi rst inject air, in equal volume, into disease states which create hypoperfusion (e.g., the vial before withdrawing the medicine to prevent anaphylactic shock). Intramuscular injection is a a vacuum. preferred route for so-called depot medications • There are many routes of injection that deliver deposited under the skin to produce sustained a drug directly into the |
target organ. Indirect therapeutic levels over a longer period of time. parenteral injections are also effective means of • There are four common sites for intramuscular delivering medications. However, the greatest injection. The fi rst site, the ventrogluteal (VG) drawback is its dependence on adequate circulation muscle, is located on the lateral thigh proximal to to reach the target organ. the hip. A more anterior injection site is the middle • Positioning the patient is the fi rst step in portion of the vastus lateralis (VL) muscle of the preparation for an injection. The injection site thigh. Requiring less exposure and easier access is selected should not be hard, swollen, or tender the deltoid muscle. The most common intramuscular and must be free of rashes, moles, birthmarks, injection site is the dorsogluteal (DG) muscle. The burns, scars, or broken skin. The Paramedic should gluteus is located proximal to the inferior portion of place an isopropyl-soaked pad on the site and, the patient’s fl ank. working outward in ever-expanding circles, prepare • EMLA cream, a topical anesthetic, can be used to an area approximately twice the length of the reduce the pain of needle insertion. Fluori-methane needle. The skin is stabilized with the Paramedic’s and vapocoolant spray are also applied directly nondominant hand and, with the needle in the to the skin for anesthetic effects. The deeper dominant hand, the needle is inserted under the muscle layers are relatively free of pain receptors, skin. With the needle in place, the Paramedic would although irritation may occur from a drug if leaked gently aspirate to ensure that the needle was not into subcutaneous tissues. To prevent this, the inadvertently placed into a vein. airlock and Z-track techniques may be used by the • Intradermal injections may be used when preparing Paramedic for intramuscular injections. an intravenous site with a local anesthetic or • The elderly and children each present a special for tuberculosis testing. The objective of an challenge to the Paramedic who must perform an intradermal injection is to place a small quantity injection. To develop strategies to improve success of medicine just under the epidermis and in close of a pediatric injection, the Paramedic must take proximity of the subcutaneous tissue. Point of care into account the child’s developmental stage and blood testing can be performed with blood glucose adjust the approach accordingly. For the elderly, analysis or fi eld troponin levels. A fi nger stick or, the combination of age and poor nutrition reduces for pediatric patients, a heel stick is performed to muscle mass, limiting available injection sites. obtain a small sample of blood for analysis. Principles of Medication Administration 547 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Review Questions: 1. Before administering any medication, what are calculate the number of drops per minute that the six rights a Paramedic is responsible for should be administered. confi rming? 5. Identify and describe the characteristics of solid 2. Explain how medication levels comparable and liquid forms of medication. to venous injection can be provided using 6. Explain why the metric system or SI is used rectally inserted medications for medication calculation as opposed to (e.g., suppositories). household measurements. 3. Defi ne what the international unit (IU) 7. What is the relationship between cubic represents and give two examples of centimeters of water and milliliters of water? medications that are administered using this 8. What complications exist when treating a system of measurement. patient with either an inhaler or nebulized 4. The Paramedic is presented with a patient medication? What can the Paramedic do to who weighs 260 pounds. Medical control overcome these challenges? has ordered that the Paramedic administer 9. Using proper anatomical terminology, describe dopamine 5 mcg/kg/min using a 60 drop the four locations for intramuscular injections. administration set. The Paramedic has one vial 10. Describe the two techniques that have been of dopamine 400 mg in 4 mL and a 250 cc bag developed to decrease the leakage and of normal saline. Write out the formula and discomfort of IM injections. Case Study Questions: Please refer to the Case Study at the beginning of the 3. What are two measures of temperature? chapter and answer the questions below: 4. You have contacted medical control, given 1. What systems of measurement exist? Why are report, and have now been given an order for protocols written in metric measurements? a medication. What are the elements of a drug 2. What are the standard metric units for length, order that should be performed when receiving a volume, and weight? medication order? 548 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). 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Relief of pain and anxiety in 2005;50(10):1313–1321; discussion 1321–1322. pediatric patients in emergency medical systems. Pediatrics. 39. Buxton LJ, Baldwin JH, et al. The effi cacy of metered-dose 2004;114(5):1348–1356. inhalers with a spacer device in the pediatric setting. J Am Acad 54. Blouin A, Molez S, et al. A novel procedure for daily Nurse Pract. 2002;14(9):390–397. measurements of hemodynamical, hematological, and 40. De Benedictis FM, Selvaggio D. Use of inhaler devices in biochemical parameters in conscious unrestrained rats. pediatric asthma. Paediatr Drugs. 2003;5(9):629–638. J Pharmacol Toxicol Methods. 2000;44(3):489–505. 41. MacIntyre NR, Cheng KC, et al. Applied PEEP during pressure 55. Yoon WY, Chung SP, et al. Analgesic pretreatment for antibiotic support reduces the inspiratory threshold load of intrinsic PEEP. skin test: vapocoolant spray vs ice cube. Am J Emerg Med. Chest. 1997;111(1):188–193. 2008;26(1):59–61. 42. Wrenn K. The hazards of defi brillation through nitroglycerin 56. Cohen Reis E, Holubkov R. Vapocoolant spray is equally patches. Ann Emerg Med. 1990;19(11):1327–1328. effective as EMLA cream in reducing immunization pain in 43. West K. Infection-control basics. A common sense review for school-aged children. Pediatrics. 1997;100(6):E5. EMS personnel. Jems. 2002;27(5):115–118, 120, 122–125. 57. Williams RH, Nollert MU. Platelet-derived NO slows thrombus 44. Tatelbaum MF. Needlestick safety and prevention act. Pain growth on a collagen type III surface. Thromb J. 2004;2(1):11. Physician. 2001;4(2):193–195. 58. Warren BL. Intramuscular injection angle: evidence for practice? 45. Redd DA, Boudreaux AM, et al. Towards less painful local Nurs Prax N Z. 2002;18(2):42–51. anesthesia. Ala Med. 1990;60(4):18–19. 59. Katsma DL, Katsma R. The myth of the 90 degrees-angle 46. Hildebrandt P. Subcutaneous absorption |
of insulin in insulin- intramuscular injection. Nurse Educ. 2000;25(1):34–37. dependent diabetic patients. Infl uence of species, physico- 60. Petousis-Harris H. Needle angle when giving i.m. vaccinations. chemical properties of insulin and physiological factors. Dan Nurs Prax N Z. 2002;18(2):52–53. Med Bull. 1991;38(4):337–346. 61. Chung JW, Ng WM, et al. An experimental study on the use of 47. Hildebrandt P, Birch K. Basal rate subcutaneous insulin infusion: manual pressure to reduce pain in intramuscular injections. J Clin absorption kinetics and relation to local blood fl ow. Diabet Med. Nurs. 2002;11(4):457–461. 1988;5(5):434–440. 62. Rodger M.A. King L. Drawing up and administering 48. Hildebrandt PR, Vaag AA. Local skin-fold thickness as a clinical intramuscular injections: a review of the literature. J Adv Nurs. predictor of depot size during basal rate infusion of insulin. 2000;31(3):574–582. Diabetes Care. 1993;16(1):1–3. 49. Zaybak A, Gunes UY, et al. Does obesity prevent the needle from reaching muscle in intramuscular injections? J Adv Nurs. 2007;58(6):552–556. 550 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. KEY CONCEPTS: Upon completion of this chapter, it is expected that the reader will understand these following concepts: • Fluid balance • Indications for intravenous access • Method for venipuncture • Complications of intravenous access • Techniques and strategies for pediatric phlebotomy and intravenous access • Alternative access points and central venous access devices Case Study: As the second unit rolled up onto the scene of a two-car MVC, the Paramedics heard from the fi rst unit that they should set up a trauma line for the driver of car #2. She was being extricated now and had signifi cant injuries. Oh, and by the way, the driver was Mrs. Gorino. Everyone knew Mrs. Gorino. She was a pleasant woman who had battled back from breast cancer but needed frequent hospitalizations for a myriad of medical problems. Only the best of the best Paramedics could fi nd IV access on her. 552 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Intravenous Access 553 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. OVERVIEW Intravenous access allows the Paramedic to administer medications and manage a patient’s intravascular volume. To effectively care for the patient, the Paramedic must have a commanding knowledge of the equipment used for intravenous access, as well as complete assessment skills and techniques. By examining the sources of fl uid loss and clinical signs of fl uid displacement, the Paramedic can determine the need for intravenous access and develop an appropriate treatment plan. Needs and skills vary according to age and clinical condition. Intravenous Access Medical lines, sometimes called lifelines, are a means of giving medications directly into the circulation. A number and Paramedics of methods have been devised to gain venous access, yet one The public distinguishes the Paramedic from basic life sup- constant remains for all of them—intravenous access is nec- port providers by the Paramedic’s ability to start intravenous essary for medication administration. access (IV). The public knows that an IV permits the Para- The second indication for intravenous access is trauma. medic to give pain medicine and other life-saving drugs. Blood losses can make the patient who has experienced Perhaps no other ALS skill is practiced as often as intrave- trauma hypovolemic. A trauma line is inserted into the vas- nous access. Therefore, the Paramedic should be an expert at cular space so that intravascular volume can be replaced and establishing intravenous access. homeostasis restored. In some cases, a patient with traumatic injury may need medications. Conversely, a medical patient may experience a signifi cant loss of fl uid and require volume Physiology Review replacement, though there has been no trauma. It is apparent that the divisions are not clean and each type of line is some- The human body is primarily made up of water, about 30 times used for the other purpose. liters of water, which is distributed across three compart- ments. When thinking of body fl uids, the fi rst compartment generally considered is the intravascular space in which the Sources of Fluid Loss blood volume is contained within the arterial, capillary, and Fluid loss, due to either illness or injury, is an indication for venous vessels. However, the bulk of the water is contained intravenous access. By understanding the sources of fl uid within the second compartment, the intracellular compart- loss, the Paramedic can anticipate the need for intravenous ment (ICF), while the remaining volume is contained in the access. Fluid loss is a normal function of the body. Such loss third compartment, the extracellular fl uid (ECF). The extra- may be apparent, such as urination, or may be unsuspected cellular fl uid (ECF) bathes the cells as interstitial fl uid. (insensible). Insensible loss is that volume of fl uid that is The constant ebb and fl ow of these fl uids across these lost from the body in the form of perspiration off the skin three compartments, exchanging gasses, hormones, glucose, (1.1 liters/daily) and the vapor in the breath. Normally, the fatty acids, and wastes, is the basis for nutritional fl ow. Using patient would replace this loss through fl uid intake as well as this nutritional fl ow to an advantage, Paramedics can inject a the water contained in the foodstuffs ingested. concentrated quantity of medication, called a bolus, into the The amount of fl uids normally lost, both sensible and intravascular space and reasonably expect that the medication insensible losses, can be accelerated by disease. Paramed- will make it into the cells of the target organ. ics who are confronted with a patient who has a medical complaint and has signs of hypoperfusion should perform a Medical vs Trauma complete history and physical assessment of the patient to ascertain the source of the fl uid loss as well as ascertain the The rationale for obtaining intravenous access can be grossly degree of hypovolemia. broken down into two categories: medical and trauma. Both A common cause of increased insensible fl uid loss is patient populations undoubtedly need venous access in cases increased perspiration secondary to fevers due to infection.1,2 of emergency, and the risk/benefi t of obtaining an intravenous This loss, combined with the anorexia (lack of appetite) line leans so decidedly toward providing benefi t that Para- that often accompanies a fever, can result in an imbalance medics attempt venous access almost all emergent patients of fl uid intake versus output. Add the vomiting and diarrhea and most urgent patients. What remains undecided is the use which often accompanies many illnesses, and the patient may of intravenous infusions in specifi c cases. quickly develop a signifi cant fl uid imbalance. 554 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. During a 24-hour period, the average person will itself is a diuretic, the impact of liver cirrhosis is probably excrete—and then reabsorb—approximately one-half of her greater upon the patient’s fl uid volume state. When the liver intravascular volume into the lumen of the intestines. This is not producing suffi cient blood proteins, such as albumin, process of excretion and reabsorption of nutrient ladened fl u- secondary to cirrhosis, the colloidal osmotic pressure (COP) ids constitutes nutritional fl ow and is essential to the body’s within the blood falls, and with it the patient’s intravascular sustenance. Any process which interferes with that fl ow can volume. create fl uid imbalances. Hyperglycemia can be another cause of acute fl uid loss. Beyond the fl uid loss that accompanies vomiting and Hyperglycemia, the hallmark of new onset diabetes mellitus, diarrhea, other gastrointestinal problems can create hypo- acts as an osmotic diuretic and draws fl uid from the interstitial volemia secondary to the fl uid loss. For example, a patient space into the central circulation. As this volume increases, with a small bowel obstruction will not be able to reabsorb the kidneys increase urine output to excrete the excess vol- the fl uids in the large bowel as the patient normally would. ume. The patient, whose tissues are now dehydrated, craves Subsequently, the fl uids excreted into the small bowel are water. Despite drinking steadily (polydipsia), the patient can- sequestered behind the obstruction, leading to a distended not take in enough fl uids to offset the excessive output from abdomen. The volume of fl uids is not returned to the central urination (polyuria). circulation as would normally occur. Draining abdominal fi stula, ileostomy, colostomy, and Physical Examination for Dehydration aggressive nasogastric tube suctioning, as well as overuse or misuse of renal diuretics, are other examples of important The patient who has lost signifi cant intravascular volume, sources of fl uid loss. secondary to dehydration, may manifest signs of hypoper- However, it is trauma, with its problematic hemorrhage, fusion which will be evident during the initial assessment. that can cause the quickest fl uid loss. Rupture of solid organs, These signs include decreased level of responsiveness, tac- such as the spleen and liver, following either blunt or pene- hypnea, tachycardia, hypotension, or postural hypotension. trating trauma can quickly create profound hypovolemia. The When these signs culminate to present a clinical picture of Paramedic is well-advised to consider occult trauma when- hypoperfusion, the Paramedic may decide to institute fl uid ever confronted with hypoperfusion of unknown origin. replacement immediately. A number of other signs may precede this presentation and suggest dehydration and impending hypoperfusion. These Past Medical History signs, in a head-to-toe fashion, are lackluster eyes, eyes that A number of pre-existing medical conditions can also contrib- are sunken into their sockets and appear dull. The absence of ute to increased fl uid loss. The following short list of medical tears in a child’s eyes should alert the Paramedic to the pres- conditions can lead to increased and/or excessive fl uid loss ence of dehydration. leading to hypovolemia; this list not all inclusive of medical Dry and cracked lips along with pale mucous membranes conditions that can lead to fl uid loss. in the oropharynx are signs of dehydration. The tongue may Diabetes insipidus, secondary to brain tumor or any other be the best external measure of the patient’s hydration. Nor- space-occupying lesion, can cause life-threatening dehydra- mally, a tongue is plump, and moistened with saliva. How- tion within hours. Diabetes insipidus causes the kidneys to ever, when a patient is dehydrated the tongue becomes dry pass the fi ltrate from the plasma almost unchanged. Normally and furrowed (furrows being long fi ssures |
in the tongue). 99% of this fi ltrate is reabsorbed. Next, the Paramedic should examine the neck, particu- Emphysema, with its accompanying persistent tachy- larly the jugular veins. Some Paramedics regard the jugular pnea, can lead to signifi cant insensible fl uid loss through rapid veins as the “dipstick” of the heart. Under normal condi- respiration. Coupled with the diuretic action of many respira- tions when a patient is lying fl at, the external jugular veins tory drugs such as aminophylline, and without adequate fl uid are at least minimally distended and clearly visible, indicat- replacement, the patient can become markedly dehydrated. ing a suffi cient blood volume. In the case of the patient who Initially, the thought of congestive heart failure summons is dehydrated, the jugular veins will lie fl at against the neck thoughts of fl uid overload, and during an acute exacerbation when the patient lies fl at. this may be the case. However, the combination of forward The next indicator of hydration is the urine output. While failure and subsequent inadequate renal perfusion, coupled not practical in the fi eld, unless the patient has an indwelling with overuse of prescribed diuretics and a constant shifting of urinary catheter, measuring a patient’s hourly urinary output fl uid volumes across all three fl uid compartments, can culmi- is an excellent indicator of vascular volume. When urine out- nate in a complicated clinical picture which can include cel- put drops below 20 mL per hour (oliguria), then the patient lular dehydration, vascular volume depletion, and electrolyte is experiencing signifi cant hypoperfusion of the kidneys, an imbalances. Heart faiulure, therefore, is a problem of fl uid early indicator of shock. maldistribution coupled with interstitial dehydration. In the hospital setting, the gold standard for fl uid bal- Despite an apparent constant intake of fl uids, the alco- ance is the patient’s weight. Even with constant monitoring holic patient is prone to fl uid defi cits as well. While alcohol and recording of intake and output, many critical care units Intravenous Access 555 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. weigh their patients regularly, in some cases daily, in order a secondary intravenous solution, through a primary infusion to monitor fl uid balance. Long-term care facilities also regu- line containing either 0.9% sodium chloride in sterile water larly weigh their patients. (0.9% NaCl) or 5% dextrose in sterile water (D W). 5 The Paramedic who looks for these early signs of dehy- dration and fl uid defi cits will not be surprised when the patient becomes hypotensive. Perhaps more importantly, Street Smart the Paramedic may be able to intervene early and prevent hypotension. A solution of 0.9% sodium chloride in sterile water Intravenous Fluids (0.9% NaCl) contains the same amount of salt as does Intravenous fl uids used for medical patients are intended to the blood. For this reason, many healthcare providers be either intravenous routes for therapeutic medications, or to refer to 0.9% NaCl as normal saline solution (NSS). be therapeutic in and of themselves. Intravenous fl uids used NSS has become an EMS standard solution in many for trauma patients are more often intended to replace lost systems because it is compatible with all medications volume and therefore are therapeutic. In the case of trauma, the optimal fl uid replacement for as well as blood. lost blood would be blood. However, current blood storage requirements and inadequate prehospital equipment make blood replacement in the fi eld impractical. In an effort to Tonicity overcome these obstacles, physicians and scientists are trying A solution is considered balanced if it has the same concentra- to create a variety of blood substitute.To date, trials of these tion of solutes to solvent as there are solutes to solvent pres- blood substitutes are falling short of expectations, but more ent in the blood. Any imbalance of this solute concentration blood substitutes are being researched. would cause an osmotic effect to be created when adminis- These blood substitutes contain proteins, and are thus tered intravenously, potentially overhydrating or dehydrating called a colloid. These colloidial fl uids are capable of both a cell. In other words, tonicity could be thought of as the pulling fl uids from within the interstitial space into the circu- solution’s ability to alter a cell’s internal fl uid balance through lation, to help augment the circulating volume, and remain- osmotic force created by the imbalance between the tonicity ing within the blood stream for a prolonged period of time, of the solution outside of the cell versus the tonicity of the helping to maintain the circulating volume. fl uid within the cell. When the percentage solute in the solu- In the interim, and until these solutions are available, tion is similar to the percentage solute in the blood, such as Paramedics must use electrolyte-containing fl uids during is the case with a balanced solution, the solution is said to trauma resuscitation. These electrolyte solutions, when dehy- be isotonic. Examples of nearly isotonic fl uids include D W, drated, create crystals. Thus, these electrolyte-containing fl u- 5 LR, and NSS. When additional substances or additives are ids are referred to as crystalloids.3-6 added, thus increasing the concentration of the solutes com- The electrolytes commonly found in crystalloid pared to blood, then the solution is said to be hypertonic. s olutions—sodium, chloride, and potassium—are the same Hypertonic solutions will, by osmotic force, draw water out electrolytes found within the blood. In fact, several crystal- of the cell, causing the cell to dehydrate and collapse or cre- loid solutions were created in an effort to reproduce a “blood- nate. Conversely, if pure sterile water, or a solution which like” mixture. British physicist Sidney Ringer was made has fewer solutes than blood, was injected, then the solution famous when he tried to create a “balanced solution” in 1873, would be referred to as a hypotonic solution. Cells would the solution which still bears his name, but was unable to then, by osmotic force, draw water into themselves, expand- bottle the solution because of its effervescence. Improving ing in the process to the point where the cell would burst. on Dr. Ringer’s solution, and solving the problem of effer- Various changes occur when isotonic, hypotonic, and hyper- vescence, Dr. Hartmann added lactate, resulting in lactated tonic solutions are mixed with red blood cells as shown in the Ringer’s solution (LR). Lactated Ringer’s solution remains following fi gure (Figure 27-1). the solution of choice of trauma surgeons (advanced trauma life support, or ATLS) and in the treatment of burn patients (American Burn Foundation or ABF).7–10 Intravenous Fluid Administration When caring for a medical patient, a number of additives Once a solution has been selected, the Paramedic turns his may be added to the solution to provide a therapeutic benefi t. attention to the administration of that fl uid. Intravenous solu- The most common additive is dextrose, a simple sugar which tions come in either plastic containers or, more rarely, glass can be quickly metabolized to meet the ill patient’s higher bottles and in volumes ranging from 25 mL to 3,000 mL. energy demands. Other additives include antibiotics, vaso- Paramedics typically use 250 mL, 500 mL, and 1 L solutions. pressors, antidysrhythmics, and a host of other medications. Glass containers are noncollapsible and must be open to air, Many of these therapeutic solutions are run intermittently, as or vented, to prevent the creation of a vacuum. While plastic 556 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Solute Free water Solute Free water molecule molecule molecule molecule Isotonic environment: The solute concentration and the Hypotonic solution: free water concentration are the same The solute concentration is greater inside and outside the cell. inside the cell; the free water Water flows in and out of the cell at an equal rate. concentration is greater outside. A Free water flows into the cell. B Solute Solute Free water molecule molecule molecule Hypertonic solution: The solute concentration is greater outside the cell; the free water concentration is greater inside. Free water flows out of the cell. C Figure 27-1 (a) Isotonic solution. (b) Hypertonic solution. (c) Hypotonic solution. containers are increasingly more common, glass containers bypasses many of the body’s defenses against infection. are still used for medications which react with or are absorbed Without these protections, the patient’s blood could become into the plastic. IV bags are soft plastic solution containers infected, a condition called septicemia, and the patient could which collapse as the solution is withdrawn, eliminating the develop a potentially life-threatening sepsis. When a Para- need for venting, and create a closed system which helps to medic starts an intravenous access, it is understood that the decrease the risk of outside contamination. Paramedic has the responsibility to take all reasonable pre- A careless infusion of intravenous fl uids can lead to seri- cautions to prevent such an occurrence. ous systemic complications. For example, contaminated intra- There are a number of occasions when the intravenous venous fl uid can lead to septic shock. An intravenous infusion fl uid can become contaminated. The intravenous solution Intravenous Access 557 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. could have become contaminated before the Paramedic han- dled the solution. The container could have been accidentally punctured, or contaminants accidentally introduced along with the additives during the manufacturing process. Under- standing this risk, every manufacturer takes precautions to prevent contamination. However, despite these precautions, contamination can still occur. Most manufacturers will only guarantee a solution’s sterility for a certain period time, a date stamped on the package. Understanding these precautions have already been taken, every Paramedic performs a three-step inspection of the solution before it is opened. After confi rming that the correct solution has been chosen, the Paramedic verifi es that the solution is not expired. The expiration date, stamped or printed on the container, is evidence that the solution is less Figure 27-2 Macro-drop intravenous likely to be contaminated. administration set. Next, the Paramedic examines the solution for clarity. Intravenous solutions are generally clear, with some notable exceptions being medications like diazepam (pale yellow). With the solution held up to a light, the Paramedic should straight line with the fewest obstructions, such as fi lters or inspect the solution for any discoloration or any particulate medication portals, is desirable. These administration sets are matter. If contamination is suspected, then the solution should referred to as macro-drop administration sets (Figure 27-2). be discarded immediately. When careful titration of medicated fl uid is desired (e.g., Finally, the Paramedic should test the container to see if when a medical patient needs a slow infusion of a drug), then it is intact and without microscopic holes that could be por- fi ne control of the infusion stream is needed. These adminis- tals for contamination. A fi rm twist of the bag should reveal tration sets are referred to as micro-drop administration sets. any leaks. If the bag does leak, it should be discarded and Anatomy of an Administration Set another solution chosen. Every administration set has a spike, sometimes called a bayonet, which is used to pierce the fl uid container. As the name implies, the spike |
is very sharp and is as capable of Street Smart cutting fl esh as easily as it is capable of piercing a plastic seal in a bag of intravenous solution. Caution should be observed Some intravenous solutions come with a second when mating the spike of the administration set to the solu- protective outer wrap around the bag. Due to tion bag to prevent inadvertent puncture of the side of the differences in humidity from the site of manufacture solution bag, which can result in a puncture of the Paramed- ic’s fi nger as well. and the present location, condensation may have Below the spike is the drip chamber. Hanging drops are occurred. The Paramedic should fi rst wipe the bag formed inside the drip chamber. These drops can be counted, down and then test the container’s integrity. Follow as drops (gtt) per minute (gtt/min), and the rate of fl ow estab- lished. If the chamber has a thin, or needle, dropper, then the this rule, however: “If in doubt, throw it out.” administration set is called a micro-drop set. By convention, all manufacturers have set 60 drops from a micro-drop set to equal 1 mL. The needle dropper is visible within the drip Administration Sets chamber (Figure 27-3). The next step in preparing to administer an intravenous solu- If the drip chamber does not have a needle dropper, then tion is connecting an administration set to the solution. Dur- the set is called a macro-drop set. Unlike the micro-drop set, ing this procedure, the greatest risk of contamination may macro-drops can vary in size. The variation in the size of the occur. Careful attention to detail is important to prevent drop directly relates to the number of drops per 1 mL. To sterile components from contacting nonsterile surfaces. The determine the drip rate for a particular macro-drop adminis- purpose of an intravenous administration set is to provide a tration set, the Paramedic should refer to the labeling on the sterile pathway for the intravenous fl uid from the container packaging. In some cases, the drip rate is embossed directly into the patient. into the plastic on the spike as well. The selection of an administration set is largely depen- Further down the length of the tubing is a drip rate con- dent upon the patient’s condition. When volume replacement trol device. The drip rate control device allows the Paramedic is needed (e.g., during a trauma resuscitation), then a short, to regulate the fl ow (i.e., the rate of drop formation) so that 558 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Figure 27-3 Micro-drop drip chamber. Figure 27-5 Intravenous administration slide clamp. Figure 27-6 In-line medication port. risk that the venous catheter will become clogged by a blood- clot, rendering it useless. To prevent the catheter from clog- ging, the check valve leaves a standing column of solution in Figure 27-4 Control devices: Roller clamp type. the line. Hard plastic in-line medication ports (Figure 27-6) provide precise volumes can be administered (drops per minute being access for injection of drugs into the solution stream. These equated to mL per hour). Most control devices have either a ports can be either capped with a self-sealing membrane, into roller clamp (Figure 27-4) or screw-type device, both of which which a needle would be inserted, or a needleless check-valve function by compressing the tubing. The roller clamp, a com- system designed to accept a syringe’s luer lock tip. mon control device, has a thumb wheel which compresses the Some intravenous administration sets have a device tubing against a hard plastic back and thus limits fl ow. called a fl ash bulb. The fl ash bulb is a soft in-line pyramid- Another control device, the slide clamp (Figure 27-5), is shaped device. When the tubing is clamped and the fl ash bulb used to cut off fl ow entirely. This is necessary during intrave- is squeezed, a show of blood can be seen in the distal tubing. nous drug boluses to prevent retrograde infusion of the medi- This blood “fl ash” is an indicator that the venous access is still cation into the intravenous tubing rather than into the patient. patent. Some fl ash bulbs are made of self-sealing materials By sliding the tubing into the groove, fl ow is stopped. Similar which permit insert of a needle for injection of medications, to a slide clamp, some administration sets have a squeeze- thus making the fl ash bulb the most proximal medication port clamp which can cut off solution fl ow. to the venous access. Some administration sets come with a mid-line, in-line Some intravenous administration sets also have an in-line check valve designed to prevent the administration set from fi lter. The in-line fi lter is designed to strain the solution for running dry. If an administration set does run dry, there is a large particles of undissolved medication, solution crystals, Intravenous Access 559 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Luer lock and adapter Drip chamber Roller clamp Spike to attatch to intravenous fluid bag Medication administration Tubing Slide clamp port Figure 27-7 Anatomy of an intravenous administration set. Figure 27-8 Trauma tubing. (Courtesy of Arrow International) contaminants, and the like. Disk-like in appearance, these in- line fi lters are usually found proximal to the drip chamber but distal to any medication ports. The place where the administration set inserts into the hub of the venous catheter is called the adaptor. The adaptor is ster- ile where it couples with the catheter hub and a cap is in place over the adaptor to prevent contamination. In some cases, the impervious hard plastic adaptor must be removed in order to allow the solution to be run through the administration set prior to insertion. In those cases, the cap must be retained to re-cover the sterile adaptor once the solution has been run out in order to maintain the sterility of the adaptor. Other adaptors have a semi-porous cap which permits fl uid to run out through the cap without compromising sterility (Figure 27-7). Street Smart Figure 27-9 Pressure bag. When the adaptor’s cap is misplaced, the administration set can be capped with a spare covered Trauma tubing generally has a larger internal diameter, or sterile needle. The diameter of the hub and a needle bore, than standard tubing (Figure 27-8). The combination of are the same. When the administration set is to be a short length and large bore allows the rapid administration of attached to the hub of the venous catheter, the large volumes of solution.15,16 This administration is so rapid, needle is then discarded into a sharps container. in fact, that some trauma tubing sets are also Y-sets, meaning that they have two fl uid connections, each with a spike. This allows two bags of solution to be hung at one time. The addition of a pressure bag can also increase the rate Trauma Tubing of fl ow and decrease the time to infuse a liter of solution. A Factors that infl uence the rate of fl ow for an administration pressure bag is a sleeve with a bladder device. The solution is set are the length of the tubing, the height of the solution bag, placed within the sleeve and the bladder exerts direct pressure and the diameter of the tubing.11–14 Tubing length may have onto the solution bag. The increased pressure subsequently the greatest impact on fl ow rates. Whenever fl uids run down increases the rate of fl ow. Infl ated in the same manner as a a tube, the fl uid strikes the walls of the tubing, creating tur- blood pressure cuff using a bulb with relief screw, a pressure bulence, and the turbulence slows the speed of the fl uid. This bag is infl ated to a preset pressure, visible on the gauge, or phenomenon is called friction loss. The longer the tubing, the until a pressure relief valve activates (Figure 27-9). greater the friction loss, and the slower the fl ow of the solu- Whenever there is a large volume of fl uid to be adminis- tion. For this reason, trauma tubing is generally short in order tered, there is the concomitant risk of inducing hypothermia to facilitate a rapid fl ow of solution into the patient. via infusion of less-than-body-temperature solutions. To 560 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. prevent this predictable complication, special warmth- The volume to be infused in children must be carefully preserving solution sleeves are available (Figure 27-10). These controlled to prevent any incidence of fl uid overload. For sleeves have one pocket for a hot pack and another for the pediatric infusions, a special in-line burette may be added. solution. There is insulation around both to prevent heat loss. A burette has another fl uid chamber above the micro-drop drip chamber. The fi rst chamber is prefi lled with a specifi ed Blood Transfusion Sets volume of fl uid from the solution bag and then the infusion Blood’s viscous nature makes it diffi cult to fl ow and thus rate is adjusted. The solution chamber of the burette is rigid; special large-bore tubing has been created for the transfusion for this reason, it has a vent to equalize pressures. Burettes of blood. Blood tubing also has a large drip chamber with a also have a built-in check valve to prevent the administration sieve-like fi lter at the bottom which prevents clots from being set from running dry. transfused (Figure 27-11). Frequently, an infusion of NSS is When it is necessary to infuse a second bag of solution also co-administered with the blood. The NSS helps to thin (e.g., a medicated solution) and only one venous access is the blood and keep the blood running freely. available, a secondary set can be set up to run through the In special cases, it is desirable to add another drug port primary administration set. This arrangement has several for concomitant drug infusions, or an additional length of advantages. It prevents the need to establish a second venous tubing to the administration set. Optional extension sets are access, which is especially important in venous-impoverished available for this purpose. The extension set connects with patients. It permits continuous hydration between intermit- the adaptor of the administration set and is connected to the tent drug infusions, such as antibiotics. Finally, it permits a venous catheter. secondary drug infusion (e.g., an antidysrhythmia drug) to be temporarily discontinued so that a potentially incompatible drug can be injected through the primary administration set after the tubing is cleared of drug by a fl uid bolus. A descrip- tion of the preparation and use of a secondary set follows later in this chapter. Preparing the Intravenous Administration Set Preparation of an intravenous administration set is done in a deliberate stepwise fashion and after practice becomes almost second nature. However, a moment of inattention to the details can set up a situation that is problematic later. After removing the chosen intravenous administration set from the packaging, taking care to not let any part of the set to drop onto the ground, the Paramedic |
should inspect the set for all of the needed components. For example, if it is anticipated that a medication will be given by injection, Figure 27-10 Intravenous solution warming then a medication port as well as a clamp should be available. sleeve. Administration sets vary and not all components are present on every set. In the next step in the preparation of an administra- tion set, the Paramedic would slide the fl ow rate control device proximal to the drip chamber and clamp the tubing closed. Clamping the tubing shut prevents premature drain- age of the drip chamber. It also places the roller clamp at eye level when the solution is suspended, or hung, and thus permits better eye-to-hand control when adjusting the fl ow rate later. The Paramedic would then set the intravenous admin- istration set aside so that the solution can be prepared. After the Paramedic has ensured that the chosen solu- tion is the correct solution, the solution is not expired, the solution is not contaminated, and the container is intact, the protective covering over the solution’s admin- istration set port can be removed. Some intravenous solu- Figure 27-11 Blood transfusion set. tions come with a medication administration port, used to Intravenous Access 561 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. inject medications into the solution, which is adjacent to In many cases, there is an impervious cap over the admin- the administration set port. If the self-sealing membrane istration set adaptor which must be removed before fl ow will covering the medication administration port is inadver- begin. The Paramedic should carefully place the cap aside, tently removed, the entire contents of the intravenous bag remembering where it was placed, so it can be replaced later. will flow out. Therefore the Paramedic should carefully After the intravenous administration tubing is cleared of choose the correct port. any air and fl uid runs freely from the end, a process called The Paramedic would then pick up the intravenous admin- running the line out, the tubing is clamped and set aside until istration set and remove the protective cover from the spike. after the venous access has been obtained. The Paramedic Carefully aligning the administration set’s spike in line with should ensure that the sterility of the solution is maintained the administration set port, the Paramedic would carefully slide by recapping the end of the administration set and keeping the the spike into the port. When the Paramedic feels resistance tubing from touching the ground. To help ensure the steril- to the spike, a one-half twist of the spike will effectively open ity of the administration set and solution, some roller clamps the administration set port by coring the membrane sealing the have a built-in clip on the roller clamp. The adaptor is simply solution and will seat the spike fi rmly into the administration set slipped into the clip and clamped into place (Skill 27-1). port. Caution should be observed when connecting the intrave- For a step-by-step demonstration of Preparation of an nous solution to the administration set. First, the administration Intravenous Adminsitration Set, please refer to Skill set’s spike is sterile. Contact with the outside of the solution’s 27-1 on page 586. administration port, the Paramedic’s fi ngers, or any other non- sterile surface will contaminate the administration set. If this occurs, then another administration set must be used. Second, Intravenous Access the spike is capable of breaching the sidewall of the administra- Venous access is an assured means of getting drugs into the tion port and piercing the Paramedic’s gloved hand. Firm con- central circulation so that they can go to the target organs and trol and deliberate action can usually avert this problem. exert their intended therapeutic effect. The speed at which a With the administration set in place and the solution held drug can be delivered to the target and confi dence that the upright so that the drip chamber is at eye level, the Paramedic dose delivered will attain the therapeutic window has made would then squeeze the drip chamber and release. If the spike venous access the preferred route for medication administra- is properly set, fl uid will start to fl ow. If there is no fl ow, then tion during an emergency. the Paramedic should advance the spike further into the solu- Emergency venous access can be divided into two types: tion bag and re-attempt the maneuver until successful. A peripheral venous access and central venous access. Periph- one-half-full drip chamber is optimal. The Paramedic should eral venous access has the advantage of ready availability. continue to squeeze the drip chamber until it is one-half full. Peripheral venous access is also compressible in the event An overfull drip chamber is not acceptable, as it does that the venous cannulation attempt is unsuccessful and not allow the Paramedic to see the drops as they form on bleeding occurs. Unfortunately, a number of circumstances, the needle. If the drip chamber is inadvertently overfi lled, the such as cardiovascular collapse during a cardiac arrest, can Paramedic would invert the solution bag and squeeze the drip make peripheral venous access more diffi cult to obtain. chamber again, replacing the solution back into the bag. Central venous access, on the other hand, uses the larger Failure to fi ll the drip chamber is also problematic. If the veins located deep inside the body. The high rate of blood fl ow drip chamber is open when the solution starts to fl ow, the stream in these veins permits drugs that are normally incompatible will entrain air into the solution and the entrained air be seen to be given sequentially and nearly simultaneously. Perhaps along the length of the tubing. While a small number of air more importantly, these large veins are still accessible, even bubbles is generally not harmful to the patient, a larger volume during times of cardiovascular collapse. Unfortunately, these of air could potentially create an air embolism. If air should veins often run parallel and proximal to arteries and nerves, accidentally get into the solution stream, as evidenced by bub- as well as adjunct to several major organs. Inadvertent arterial bles along the length of the tubing, the Paramedic should pull access, nerve damage, and organ damage are attendant risks the tubing taut and gently snap the tubing to dislodge the bub- with central venous access.17–19 For example, a pneumothorax bles, which should then fl oat upward into the drip chamber. is a predictable complication of central venous cannulation of With the drip chamber one-half full, the Paramedic releases the subclavian vein. While central venous access is practiced the clamp and allows solution to fi ll the tubing. If the stream in the fi eld by some Paramedics, the majority of venous access is too fast, then turbulence in the drip chamber will entrain air obtained by Paramedics is peripheral venous access. The fol- into the tubing where it will adhere to the tubing walls. A slow lowing sections discuss the details of obtaining peripheral steady stream of solution clears the tubing of air and prevents venous access and accessing central venous devices. air bubbles from forming along the tubing’s walls. If after releasing the clamp there is no fl ow, then the Paramedic should examine the length of the tubing, starting Peripheral Venous Access Devices at the drip chamber, for a closed slide clamp or other signs of Early intravenous access devices were large hollow-bore obstruction of the tubing. straight needles which were placed, whole-length, into a 562 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. vein. These early needles had to be sharpened by hand on The tip of the needle (small portion lies exposed at the a stone and then sterilized overnight in an autoclave for end of the plastic catheter) has a short bevel tip which permits surgery the next day. Current venous access devices can be easy penetration of the skin while lessening the chance of either metal or plastic and are sterilized when they are pack- accidental puncture of the distal wall of the vein. The length aged. Manufactured with precision machines to exacting of the needle and catheter, like the hypodermic needle, is standards, these catheters are extremely sharp and come in a dependent on the size of the patient. Pediatric IVs may be 1/2 variety of sizes. to 1 inch long, while the average adult IV is 1 1/2 inches long. The size of an intravenous needle is measured as a Extra long needles, 3 to 4 inches long, are used for special gauge—the smaller the gauge, then the larger the needle. populations of patients such as the patient with severe burns Typical intravenous needles start at 12 gauge and go down to (where subcutaneous swelling can literally pull an IV out) 24 gauge. The selection of the gauge, as well as the selection and obese patients. of the intravenous administration set, depends on its intended Butterfl y IV catheters, a throwback to the days of steel use. A larger needle is preferred for trauma patients in that it needles, are still used for pediatric patients. These shorter can be anticipated that either viscous blood or large volumes steel needles are embedded into a plastic anchor device of crystalloids will be infused. Blood transfused through a which has wings, like a butterfl y. Grasping the wings permits smaller gauge needle (less than 18 gauge) can cause physical the Paramedic better control of the needle during insertion, destruction (lysis) of red blood cells.20, 21 as well as a fi rm surface to anchor the device against the skin Smaller gauge needles (e.g., a 20 gauge needle) are pref- when securing the device in place. This makes them popular erable if the Paramedic anticipates the venous access will for use in the pediatric population. be maintained for a longer period of time. A smaller gauge The third venous access device is the needle-over-the- needle decreases the incidence of thrombophlebitis. Throm- catheter device. These devices are used almost exclusively for bophlebitis occurs more readily in veins cannulated with a central venous access, in part because there are more steps to large-bore needle than a small-bore needle because the large- perform during insertion; the Seldinger technique. Use of the bore needle occupies more of the lumen of the vein, slow- needle-over-the-catheter device is discussed further in a later ing blood fl ow, and creating optimal conditions for platelet section on central venous access. aggregation, the nadir for a thrombus. Needle Safety Categories of Venous Access Devices Accidental needlestick injuries present the Paramedic with the The most widely used intravenous (IV) access devices are the greatest risk for an occupational exposure to HIV and other catheter over the needle devices (Figure 27-12). Individually blood-borne pathogens.22 IV catheter manufacturers have packaged, with a large number of gauges and lengths avail- developed a number of “engineered” safety features which able for selection, these IV devices are easy to insert. appear in newer IV catheters, in an effort to decrease the inci- The heart of a catheter-over-the-needle IV device is the dence of preventable needlestick injuries. Paramedics should needle. The hollow-bored needle acts as a rigid introducer make use of this available safety technology ( Figure 27-13). into the vein and allows blood to backup into the needle Whenever an intravenous access is attempted, a sharps con- to become visible to the Paramedic. The catheter-over-the- tainer should be immediately available (i.e., within arm’s needle device allows the Paramedic to thread the plastic cath- reach of |
the Paramedic). eter over the needle and into the vein. When the insertion is complete, the metal needle is withdrawn—all that remains inside the vein is the plastic catheter. Street Smart The phrase “Use and drop” refers to the process of using a needle (IV catheter, IM or SQ needle) and being able to immediately drop it into the sharps container without taking a step away from the patient or turning away from the patient. Peripheral Site Selection While any vein in an extremity is considered a peripheral vein, certain veins have more desirable qualities than others. Figure 27-12 Catheter-over-the-needle devices. These veins are preferred by Paramedics for venous access. Intravenous Access 563 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Figure 27-13 Engineered safety catheter. The following text describes the steps taken to obtain intra- venous access. While it is easy to see some surface veins, deeper and less visible veins may be more desirable. These deeper veins are anchored in subcutaneous fat, helping to stabilize Figure 27-14 Gaining access in the axillary them and prevent them from moving, or rolling, away from vein. the needle. They are also generally larger in diameter. To distend these veins, making them easier to either visual- ize or palpate, a venous tourniquet is applied.23 A venous tourniquet is made of a soft, wide material which can apply a constricting force around the circumference of a limb. Examples of materials used for a tourniquet include leather straps, blood pressure cuffs, and rubber strips. A popular tourniquet is a length of penrose drain. A penrose drain is a tubular rubber hose which lies fl at and provides a wide band of compression. The tourniquet is typically placed around the arm, either above the elbow or above the wrist, and then tied into a slip knot, with the knot on the medial surface. Next, the distal pulse is palpated. A distal arterial pulse should remain pal- pable at all times and the limb should not become cyanotic. If the pulse is obliterated and/or the patient’s limb becomes cyanotic, then the tourniquet should be immediately removed. Figure 27-15 Gaining IV access in a potentially As a general rule, a venous tourniquet should not remain in violent patient using the basilic vein. place for more than a few minutes. In most cases, the Para- medic can accomplish all of the tasks needed to obtain venous access within that time period. The next vein, the basilic vein, runs down the dorsal After a moment, the veins will start to distend and aspect of the arm and ends at the medial wrist. The basilic become more visible. Starting proximal and moving distal, vein is particularly advantageous when trying to start an IV the Paramedic should be able to identify the following veins: on a confused or combative patient. The Paramedic would axillary, basilic, cephalic, and dorsal arch. position himself at the head of the stretcher and pull the The axillary vein (Figure 27-14) runs from the shoulder patient’s arm toward him. With the arm bent at the elbow, the over the biceps toward the elbow. This vein is more prominent arm can essentially be locked into position, permitting unim- in thin people and those who do considerable lifting for a peded access to the vein (Figure 27-15). living. The advantage of the axillary vein is two-fold. One is The vein running down the forearm, immediately oppo- its proximity to the trunk. This is particularly advantageous site the basilic, is the cephalic vein. The cephalic vein runs when administering certain medications, such as adenosine. down the lateral aspect of the forearm and terminates proxi- The axillary vein also has fewer valves than other more distal mal to the thumb. The distal portion of the cephalic vein is veins, making it easier to cannulate. most commonly used by Paramedics (Figure 27-16). 564 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Figure 27-17 Gaining IV access in the dorsal arch. Figure 27-16 Gaining IV access in the cephalic vein. To stabilize the cephalic vein, the Paramedic takes the patient’s hand as if shaking hands. With a fi rm grasp of the hand, the Paramedic palpates for a void at the distal forearm called the autonomic sniff box. The cephalic vein generally lies within the autonomic sniff box. The most distal peripheral veins of the arm are part of the dorsal venous plexus, a group of veins that originate between each digit and from an arch across the dorsum of the hand. Figure 27-18 Gaining IV access in the external While the veins of the dorsal arch are generally the most visi- jugular vein. ble, making them appear attractive to Paramedics, they contain a number of valves and tend to be somewhat torturous. If an the intended insertion side, the external jugular vein should IV is to be attempted here, a short 1-inch needle is preferred. be clearly visible. The EJV starts proximal to the angle of the To start an IV in the dorsal arch of the hand, the Paramedic jaw and inferior to the ear and then takes a relatively straight should fi rst grasp the fi ngers and bend them inward toward the course toward the mid-clavicular line (Figure 27-18). palm. With the fi ngers stabilized by the thumb, the Paramedic The saphenous vein, often overlooked by Paramedics, can proceed with insertion of the IV (Figure 27-17). Gener- provides an excellent point for venous access when the upper ally, the plane of the insertion of the needle is sharper as the extremities are not available, perhaps due to burns or fractures, veins of the hand are more superfi cial. for example.26, 27 The long saphenous vein, one of two superfi cial Although the external jugular vein (EJV), strictly speak- veins in the leg, is the longest vein in the body, stretching from ing, is not a peripheral venous access, it is treated as such by the groin to the foot. The short saphenous vein extends from the many Paramedics because it can be easily visualized, readily top of the foot, proximal to the outer or lateral malleolus, then palpated, and more importantly, it is compressible if extravasa- runs alongside it, then crosses the Achilles tendon to end in the tion should occur. Because of its location, the actual method of middle of the back of the knee and connects with the popliteal preparing the site for insertion of an IV device is slightly differ- vein. Both saphenous veins communicate with deeper veins via ent. To identify the external jugular vein, the patient should be bridging veins called perforators, which literally perforate the placed in a supine position to maximize venous return.24,25 fascia of the muscle bundles to connect with the deeper veins. While it would be impractical to apply a tourniquet This unique aspect of the saphenous vein permits drugs given around a patient’s neck, it is possible to compress (tampon- via this route to gain rapid access to the larger veins of the legs. ade) the vein by applying a thumb to the distal portion of Some patients, particularly patients with diabetes, have the external jugular vein just superior to the clavicle, at the poor circulation in the lower extremities. This poor circula- mid-clavicular line. By turning the patient’s head away from tion tends to retard healing of a wound. Therefore, Paramedics Intravenous Access 565 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. generally avoid starting an IV in the foot if the patient is Diffi cult Venous Access known to have diabetes or poor circulation in the extremi- Patients who are elderly, who have undergone chemotherapy, ties (peripheral vascular insuffi ciency). Other signs of poor who have a poor nutritional status, or who are obese, plus a circulation in the feet include misshapen toenails and distal number of other medical conditions, may have a poverty of cyanosis of the toes when dependent. visible peripheral veins. These patients present a special chal- lenge to the Paramedic. To improve venous fi lling of the peripheral veins, it is Street Smart important to maintain the limb in the dependent position, below the heart. Elevating the limb to “eye level,” instead of Knowing the exact peripheral venous anatomy is kneeling next to the patient, will quickly drain the limb and advantageous to the Paramedic confronted with a the venous distention will be gone. Some Paramedics advocate applying a warm wrap patient who is in cardiovascular collapse or arrest when around the dependent limb approximately 10 minutes before the veins are not visible. By starting distal and working the IV access is to be attempted. This technique is accept- proximal, the Paramedic can make a series of calculated able, but caution is advised when applying heat to the skin of “blind sticks” in an effort to secure venous access for the elderly patient or those with impaired sensation. Uninten- tional burns can occur due to the application of heat pads. the administration of potentially life-saving drugs. Indirect (tangential) lighting from a fl ashlight held to the side of the patient’s arm may also improve venous visibility. The basilic vein, the cephalic vein, and several bridging veins However, the best results are obtained when the Paramedic between the basilic and the cephalic veins, including the cubital has an understanding of peripheral venous anatomy combined vein, exist in the area of the anterior elbow, called the antecubital with gentle palpation of the forearm to detect deeper veins. fossa (AC). Some Paramedics prefer to obtain venous access in When a vein is palpated under the skin, it should rebound this area, perhaps because of their experience of having observed (i.e., feel spongy). If the Paramedic is unsure if the structure test blood drawn (phlebotomy) from the area. The decision to palpated is a tendon or vein, then she should ask the patient attempt an IV access in the antecubital fossa should be made only to move the extremity through a slight range of motion while after careful considerations of the risks. The antecubital fossa is palpating. Tendons will move with the motion whereas the a part of the elbow joint. Intravenous access obtained proximate vein will not. to the elbow joint risks being dislodged if the patient should sud- Every vein should be palpated to ensure that the vein is denly bend the joint or move the arm. To prevent this occurrence, not an artery. In low output states (i.e., hypoperfusion), it may it may be necessary to restrict the patient’s movements by secur- be diffi cult to distinguish an artery from a vein. To compli- ing the arm to a rigid armboard. cate matters, some arteries, nerves, and veins run together as To complicate matters, the median nerve, the brachial a bundle deeper in the extremity and proximal to bone. In the artery, the radial bone, the ulna bone, the humerus bone, the circumstance that an artery is accidentally cannulated, blood basilic vein, and the cephalic vein, plus numerous muscles, ten- may rapidly back up the administration set and pulsations dons, and ligaments, cross through or terminate in the elbow.28, 29 may be visible in the column of blood. In those cases, the Accidental infi ltration |
of an IV that contains hyperosmolar or catheter should be removed immediately and a direct pres- caustic chemicals (e.g., dextrose 50% or dopamine) for exam- sure applied to the arterial puncture site (Skill 27-2). ple, can create tissue ischemia and necrosis of structures within For a step-by-step demonstration of Venous the elbow, possibly leading to permanent disability. Cannulation Using a Catheter-Over-the-Needle Device, please refer to Skill 27-2 on pages 587–588. Street Smart Venous Site Precautions During a cardiac arrest, the veins of the antecubital During an emergency, any venous access is acceptable, how- fossa may represent the Paramedic’s best opportunity ever, when time permits, and under special circumstances, the Paramedic should carefully consider the alternative IV to obtain IV access during the emergency. The diffi culty access sites. For example, if the patient is suspected of hav- arises when the Paramedic has to distinguish an artery ing an acute myocardial infarction, then attempts to obtain IV from a vein. To avoid accidental arterial puncture, access in the right antecubital fossa are reserved until last. The Paramedics routinely attempt the IV access on the right AC is a preferred access site for interventional cardiac procedures, such as angiocatheterization and angioplasty. lateral side, opposite of the location of the brachial As a courtesy to the patient, it is preferred that the IV site artery on the medial side of the antecubital fossa. selected be on the nondominant arm. This allows the patient greater fl exibility and movement, including the ability to 566 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. attend to the activities of daily living (ADL) such as sign- Site Preparation and Disinfection ing admission papers. To quickly ascertain the nondominant Properly preparing the patient prior to placement of the hand, the Paramedic should look for a wristwatch. In most peripheral catheter will help to ensure success. The patient cases, the patient will wear the watch on the nondominant should be assisted to a comfortable position (such as semi- hand. If the watch must be removed to obtain an IV access or Fowler’s, if possible) and an informed consent obtained for to prevent damage to the watch, the Paramedic should make a the IV insertion using the AIR mnemonic. The patient’s arm notation on the patient care report (PCR) including a notation should be removed from his shirt sleeve, or, if practical, the as to whom the watch was given. patient should be instructed to put on a gown. A moment of Several medical conditions, such as long bone fractures, preparation prevents having to “string” the IV solution and burns, and breast cancer, preclude the Paramedic from start- administration set through the patient’s clothing in order to put ing an IV on an affected limb, except under extraordinary on a hospital gown upon arrival at the emergency department circumstances. The Paramedic should make careful note of and risk accidentally dislodging the IV access in the process. these conditions and avoid starting an IV on the affected limb Next, the Paramedic should apply the tourniquet. After if at all possible. applying the tourniquet, the Paramedic should carefully con- The presence of an armboard to stabilize a fracture may sider potential sites for IV access and select a primary site as be seen as an invitation to start an IV on the immobilized well as a secondary site. Then, with the necessary supplies limb. However, the circulation surrounding a bone fracture assembled, including a padded arm splint if the IV access is may be disrupted and infi ltration of intravenous solutions into going to be near a joint, the Paramedic is ready to prepare the the injury may further complicate the patient’s care. There- area. The following procedure is recommended; however, dif- fore, IVs are generally not started on injured limbs. ferent systems have different approaches to IV site prepara- Burns represent another relative contraindication to an tion, so local/regional procedures should be followed. IV access. Whenever alternative access sites are available, the After opening an isopropyl alcohol-soaked gauze (i.e., a Paramedic is encouraged to use them. However, if the patient prep pad), the Paramedic liberally swabs the area, removing has sustained massive burns, and no other sites are available, gross surface contaminates and skin oils. The prep pad is placed some burn authorities advocate starting the IV through the burn exactly where the IV access will be attempted and moved out- tissue. ward in ever-widening circles. The purpose of this fi rst wash is When an intravenous solution is infused, it remains in to remove sweat, dirt, and oils that could undermine the dressing. the circulation until a number of factors, such as decreased Therefore, the area cleansed should be liberal, approximately the colloidal osmotic pressure, combine to create a mismatch same area to be covered by the dressing, bandage, and tape. between the actual tonicity of the patient’s blood and the It is diffi cult to get tape to adhere to the grossly diaphoretic tonicity of the intravenous solution and cause it to shift into patient. One tactic is to apply tincture of benzoin to help the the third space, the interstitial fl uid. For example, it has been dressing remain fast. After placing a small quantity of tincture estimated that NSS only remains in the bloodstream for about 20 to 30 minutes before it “leaks” into the tissues.30, 31 of benzoin on a gauze pad, the Paramedic swabs the area around Thus the perimeter of the IV insertion site. It is important to not swab intravenous infusions can create an increase in interstitial the insertion site directly, as benzoin is not an astringent. After fl uid. Normally, the body’s lymphatic system would help to the benzoin has dried, the tape/dressing can be applied. drain the excess interstitial fl uid out of the tissues, and back in the central circulation, bringing the body’s fl uids back into balance. However, patients with breast cancer frequently Professional Paramedic undergo a procedure called an axillary lymph node dissec- tion, as a part of a diagnostic or therapeutic intervention for the cancer. These patients may no longer be able to drain the Some jurisdictions allow Paramedics to draw a blood excess fl uid from the affected limb, and a condition called alcohol sample for law enforcement offi cers (LEO), lymphedema sets into the affected limb. Lymphedema, provided there is patient consent. In this situation, unchecked, can cause swelling of the limb, compression of nerves, and paralysis. For this reason, Paramedics avoid the Paramedic should use povidone only to prepare starting an IV on the same side as the axillary lymph node the venipuncture site to avoid claims of contamination dissection.32–34 Frequently, these patients have been educated of the sample with the isopropyl alcohol used in the to warn Paramedics about starting an IV, or taking blood pressures, on the affected side, and many wear medical alert wipes. The Paramedic should document the use of bracelets warning that the patient has lymphedema. If the povidone only on his chart. patient is unconscious and has had a mastectomy, or is wear- ing a compression stocking on the arm, or there is surgical scar in the axilla, then the Paramedic should assume that an A germicidal wash follows, such as povidone-iodine-based solu- axillary lymph node dissection has taken place and choose tions (Betadine®), and is applied in the same fashion as the pre- another site for venous access. vious wash, starting at the intended insertion site and sweeping Intravenous Access 567 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. outward in expanding and ever-widening circles. Regardless of the IV needle. The IV needle and catheter should be exam- whether the Paramedic is using a prep pad or a swab for the ger- ined for any burrs which could cause the patient pain. Under micidal wash, the wipe should never re-cross an already washed no circumstances should the catheter be slid up and down the area. The Paramedic is attempting to create a mini-sterile fi eld. needle. Sliding the catheter over the needle in this fashion The area of the circular sterile fi eld should minimally be twice risks shearing the end of the catheter and creating a catheter the length of the IV needle—one length under the IV needle embolism. However, it is not uncommon to rotate the cath- as it approaches the insertion site and another length for the eter around the shaft of the needle to ensure its easy removal distance under the skin where the IV needle will be lodged. The from the needle. Satisfi ed that the IV needle and catheter are germicidal solution should be allowed to dry. This will allow for acceptable, the Paramedic would grasp the IV needle between the maximum germicidal effect. the thumb and forefi nger and approach the selected site. Paramedics can gently palpate the site before the site Some Paramedics use the nondominant hand to grasp preparation, to help identify a viable vein. However, the Para- the skin below the IV site, applying gentle stabilization to medic should not re-palpate the intended IV access site once the vein with the thumb. This helps to prevent the vein from the site preparation has begun. Placing a gloved fi nger on a moving under the skin (i.e., rolling). Rolling veins are more sterile fi eld contaminates the fi eld, forcing the Paramedic to common in the elderly who have less subcutaneous fat and re-cleanse the area. collagen to help stabilize the vein. Other Paramedics prefer to use the nondominant hand to stabilize the limb, encircling the limb with the Paramedic’s own hand below the site. If the Street Smart patient should suddenly try to pull the limb away, once the IV needle has been inserted, the Paramedic can help hold the limb in place while trying to calm the patient. This approach If the patient is sensitive, or allergic, to povidone- is particularly useful in children. iodine-based solutions, then the Paramedic should With the IV needle poised above the intended venous only use an isopropyl alcohol-soaked gauze to cleanse access point, the Paramedic can take one of two approaches for venous cannulation, the process of threading a catheter the site. When practical, alcohol-soaked gauze should into a vein. The fi rst approach is a direct in-line approach in be placed on the site and allowed to remain in place which the IV needle immediately enters the vein. The alterna- until the Paramedic is ready to insert the IV needle. tive approach is the indirect approach. With the indirect approach, the Paramedic inserts the IV needle under the skin and next to the vein. Once the needle is under the skin and next to the vein, the Paramedic changes the line of approach and enters the vein. The indirect approach is Professional Paramedic useful in people with thicker skin as well as children who are likely to fl inch. After the needle has pierced the skin, the Many hospital IV teams use a chlorhexidine Paramedic can pause, allowing the patient to recover from isopropyl alcohol-soaked swab for IV access the pain before proceeding. The indirect approach also helps decrease the incidence of “overdrive,” an accidental through preparation. These are more expensive than plain and through venous puncture. The indirect approach is some- alcohol and povidone-iodine but may offer improved times preferred by less-experienced Paramedics who are try- bacteriocidal effects. The professional Paramedic will ing to gain practice experience. monitor the literature in order to promote evidence- With the direct approach, the IV needle is placed imme- diately atop the vein. |
With the bevel of the IV needle facing based practice for his/her agency. up, the IV needle is inserted at an approximately 45-degree angle. When the IV needle is in contact with the vein, the Paramedic may feel a slight resistance to forward motion. Using a new alcohol prep pad for this fi nal step, the Para- When this resistance is overcome, some Paramedics refer to medic sets the alcohol prep pad on the insertion site and swipes this as the “pop.” This indicates the needle is in the lumen of distally, removing some of the dried povidone-iodine solution the vein and a blood fl ash should be observed distal to the from the skin; if an alternative germicidal solution was used needle hub. Absence of blood in the needle and catheter (the then this step is unnecessary. The vein should now be visible fl ash) implies that the IV is not in the vein. underneath the skin. The entire process of site selection and With the IV needle assumed to be in the lumen of the vein, preparation should take approximately one minute. the Paramedic should decrease the angle of approach to par- Venipuncture allel the vein and then advance the IV needle approximately ¼ to ½ inch to ensure that the IV needle and catheter are After careful consideration, the Paramedic would select the clearly inside the vein. By failing to perform this maneuver, preferred IV device, remove it from the packaging, and uncap the Paramedic risks losing the IV access. The purpose of this 568 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. maneuver is not just to ensure that the IV needle is inside the then place the thumb and forefi nger of the nondominant hand vein, but also that the IV catheter (which is approximately 1/4 on the EJV. The thumb should tamponade the blood fl ow, inch behind the tip of the needle) is also inside the vein. causing the vein to distend, and the forefi nger should stabilize the EJV in the supraclavicular space. From this stance, the Paramedic would place the IV needle directly over the pre- Street Smart pared EJV site. The angle of insertion for an EJV cannulation is more parallel to the skin, approximately 30 degrees, than Even the short length of the bevel of an IV needle can the angle of insertion for other peripheral IVs. The IV needle is then advanced until a fl ash is witnessed. be too long for a small vein. To reduce the chance The insertion of an IV needle into the external jugular vein of puncturing the posterior wall of the vein, some creates a neck wound. The concern with neck wounds is that Paramedics advocate rotating the IV needle so that room air can be drawn into the wound, creating an air embo- lism. To minimize this risk, the Paramedic should wait until the the bevel is down, decreasing the area of exposure patient exhales before attaching the IV administration set adap- and the chance for error. This technique may be tor.35, 36 Once the EJV IV is in place, precautions should be taken helpful, particularly in venous access in the elderly. to protect the site. The patient’s head should remain in a neutral in-line position. Some Paramedics apply a cervical collar or use a cervical immobilization device to help protect the site. Once the IV needle and catheter are within the lumen, the catheter is threaded off the needle and into the vein. It is impor- Blood Samples tant to realize that the needle is not withdrawn from the vein, Obtaining, or drawing, blood samples from an IV site is easy and but rather the catheter is threaded into the vein. The needle could potentially prevent an additional needlestick, saving the remains in place to help maintain the patency of the incision. patient from avoidable pain and other healthcare providers from If the nondominant hand is available and not holding sta- a potential needle exposure. The most commonly used blood bilization, it can be used to advance the catheter into the vein. drawing system is the vacuum-tube system. To use this system, Otherwise, the fi rst two fi ngers can grasp the hub of the cath- the Paramedic preassembles the vacuum tube collection device eter, in a pincer-like maneuver, and advance the catheter. With and sets it aside for use after the IV access is obtained. the complete length of the IV catheter in place, the needle can With the catheter in place, the Paramedic would with- be withdrawn slightly. Leaving the IV needle inside the IV draw the needle and attach the needleless adaptor to the hub hub blocks the catheter’s lumen and prevents bleeding through of the IV catheter. With the adaptor in place, the Paramedic the catheter until the Paramedic can tamponade the vein. inserts a blood tube into the barrel. Grasping the fl ange of the In anticipation of either attaching the IV administration device stabilizes the assembly. The blood tube is now pushed set adaptor or a blood sampling device, the Paramedic should down, by the thumb, over the covered needle inside the bar- manually tamponade the vein. To tamponade a vein, the Para- rel. The needle pierces the rubber stopper and the vacuum medic applies pressure above the end of the catheter in the draws blood into the tube. vein, which should be just above the sterile fi eld. Some Para- This process is repeated until all of the blood tubes are medics also elect to place a small gauze pad under the hub to fi lled. Then the device is removed and replaced with the adap- catch any bleeding at this time. tor of the administration set. More information regarding types When the needle is completely withdrawn, it must and uses of blood sampling tubes is found later in this chapter. be immediately rendered safe. Some IV needles are self- sheaving whereas others are not. Regardless of the presence of any engineered safety devices, all IV needles should be Street Smart immediately placed in a sharps container. The entire time for insertion should be approximately two minutes, from the time the tourniquet was applied to the time Pediatric veins tend to collapse under the vacuum the tourniquet was released. Proper preparation of supplies, pre- produced by adult vacuum tube systems. For pediatric assembled as necessary, helps to improve overall effi ciency. patients, the blood should be drawn using either a Cannulation of the External Jugular Vein pediatric vacuum tube system or a small syringe. The insertion of an IV into an external jugular vein (EJV) The syringe offers the advantage of low pressure, requires a few modifi cations in technique, but the procedure permitting the Paramedic to gently aspirate a blood is largely the same as for inserting any peripheral IV. To dis- sample. Once the syringe is full, then the rubber tend the vein, the patient should be placed supine, preferably stopper is removed from the tube and the blood with legs slightly elevated about 6 to 12 inches off the fl oor in modifi ed Trendelenburg position. Standing or sitting at the ejected into the tube. patient’s head and facing the patient, the Paramedic would Intravenous Access 569 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Continuous or Intermittent Infusion Once IV access has been obtained, the Paramedic has the choice between instituting a continuous infusion or an intermittent infusion. To establish a continuous infusion, the Paramedic would take the adaptor from the intravenous administration set, remove the protective cap, withdraw the needle completely from the catheter while maintaining tam- ponade, and attach the adaptor to the hub. Once the intrave- nous administration set is attached, the Paramedic would then release the roller clamp and allow the fl uid to fl ow freely for a moment. If the fl uid does not run, it may be a sign of a misplaced or dislodged IV catheter. To troubleshoot the problem, the Para- medic should check to see if the tourniquet has been removed. One of the more common reasons that the fl uid is not running Figure 27-19 Saline lock. freely is that the tourniquet may have inadvertently been left in place (e.g., covered by a falling sleeve) and out of the Para- medic’s sight. Next, the Paramedic would start at the solution and methodically examine down the length of the administra- Securing the Intravenous Catheter tion set for possible mechanical obstructions to fl ow. A gentle With either the administration set attached or the saline lock squeeze of the drip chamber should indicate if there is a pas- in place, the entire apparatus needs to be protected from acci- sage between the solution and the spike. Continuing down the dental displacement. Many Paramedics elect to secure the IV length of the tubing, the Paramedic would check all clamps hub in place with tape, even if a commercial IV dressing is and control devices to ensure that they are open. Inspection of to be used later. There are various kinds of tape available and the tubing may reveal that a tiny obstruction, such as a plug each has its advantages. from the IV solution bag, has lodged in the fi lter, or that the Standard 1/2-inch “silk” tape, adhesive applied to a tubing is kinked. Barring any obstructions in the administra- woven nylon backing, is ideal in most circumstances. If 1/2- tion set, which should have run freely before it was attached, inch tape is not available, then larger sizes, such as 1 inch, can the Paramedic would next observe the insertion site. be divided into two 1/2-inch strips. The diffi culty may lie with the catheter itself. Sometimes The adhesive of standard tape may be too strong for frag- a catheter will become lodged against the posterior wall of a ile skin (e.g., on the elderly patient or the neonate). Remov- vein or against a valve. To unblock the catheter, it merely has ing standard tape from their skin can cause a skin tear. For to be withdrawn slightly and the fl ow reattempted. If all these those patient populations, a paper-backed tape may be more measures fail, then it can be assumed that the IV catheter is appropriate. While paper tape is gentler on the skin, it does not in the vein and the IV catheter should be withdrawn. not adhere as well. The IV dressing should be constantly If the fl uid is running freely, then the Paramedic would monitored. observe the insertion site for any swelling, a sign of infi l- With two approximately 6-inch lengths of tape pre- tration. If swelling is observed, then it can be assumed that pared, the Paramedic may elect to use one of two methods to either the catheter slipped out of the insertion site or that the secure the hub. The fi rst method, called the chevron method, needle, when inserted, was driven through the posterior wall involves slipping the inverted tape, sticky side up, under the of the vein, creating a hole in the vein. Regardless, the IV site hub until it adheres to the hub, then crossing it over the hub. is no longer usable, the IV is “blown,” and the catheter must When completed and in place, the tails of the tape extend at be removed. A description of how to remove an IV catheter an approximately 90-degree angle from the site, forming a V follows shortly. shape. When the tape chevron is in place, the tape should not Alternatively, |
if intermittent infusion is indicated then be directly in contact with the catheter or cover the insertion the IV catheter can be “capped” with a plug-like device that site (Figure 27-20). In some cases, it is advantageous to place appears and functions like the medication port on the admin- two chevrons, each opposite the other. Once the chevron is istration set. In the past, an intermittent infusion device was secured, another length of tape can be placed directly over fi lled with heparin, and described as a heparin well. Research the hub. has indicated that the use of heparin to prevent thrombus for- An alternative to the chevron method is called a “squared mation at the distal catheter tip was unnecessary. Simply fi ll- out” method. Like the chevron method, a length of tape is ing the intermittent infusion device with saline would seal, slid under the hub of the needle. But instead of immediately or lock, the device and prevent thrombus formation. Sub- turning the ends, an approximately 1-inch span of tape is left sequently, saline locks have been used almost exclusively exposed under the hub and the ends turned out at a 90-degree (Figure 27-19). angle. With the fi rst tape in place, another strip of tape is 570 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Figure 27-20 Tape chevron. Figure 27-21 Transparent membrane dressing. placed directly across the fi rst piece and the hub of the cath- eter. The hub of the catheter, now encircled by tape, is secure as long as the tape adheres to the skin. To protect the insertion site, which is a puncture wound, either a dry sterile dressing (DSD), such as a gauze pad, or a self-adhesive bandage may be applied. Many Paramedics apply a small quantity of antibiotic ointment to the insertion site before applying the dressing. Commercially available anti- biotic creams (e.g., Neosporin®) applied at the insertion site create a physical barrier to bacteria and prevent capillary action from wicking contaminated oils from the skin into the wound. Street Smart If a povidone-iodine-based solution was not used Figure 27-22 Omega loop. to wash the site prior to IV insertion, then the application of a dab of antibiotic cream to the site The fi nal step in securing an intravenous infusion is to can help decrease the incidence of infection. Only a tape the intravenous administration set tubing to the patient. small amount is necessary. Too much antibiotic cream Initially, a strip of tape is laid across the adaptor and against can undermine the dressing, causing it to fall off. the skin. Then a loop of tubing is taped across the fi rst strip of tape. This creates a stress loop, called an omega loop, which will absorb any tension on the tubing and potentially prevent Many Paramedics choose to use commercially available the IV catheter from being displaced (Figure 27-22). transparent membrane dressings (Figure 27-21). These trans- parent membrane dressings have several advantages which Adjusting the Infusion Rate make them attractive for fi eld use. Since they are prepack- Before starting any infusion, it is important that the Para- aged in individual sterile packets, transparent membrane medic review the indications for the infusion as well as the dressings are convenient to use. Once a transparent dressing contraindications. A reassessment of the patient’s vital signs, is applied, the moisture under the dressing can pass through jugular venous distention, and lung sounds should be made. the semipermeable membrane while microorganisms, such as Then the Paramedic should check for signs of pulmonary bacteria, cannot pass under the dressing and into the wound. edema to establish a baseline. Furthermore, transparent membrane dressings allow the Para- The selection of an intravenous administration, in part, medic the opportunity to continuously monitor the insertion determines the rate of infusion. For example, a micro-drop site for signs of infl ammation and infi ltration without break- administration set cannot produce the same volume of fl ow ing down the dressing. This is an advantage when injecting in mL per hour, even when the fl uid is running as a straight medications. stream, that a macro-drip administration set can. Intravenous Access 571 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Conversely, it is more diffi cult to dispense a precise volume case with any overdose, a runaway infusion must be reported for infusion using a macro-drop intravenous administration to medical control so that appropriate measures can be taken to set. For this reason, Paramedics use micro-drop intravenous mitigate the medication’s adverse effects and negative impact. administration sets as a standard practice for medication infu- The value of prehospital intravenous infusions for trauma sions to help ensure that the exact dose is administered. When patients is being debated. Early consensus seems to indicate a precise volume of infusion is needed, the Paramedic would that a minimal infusion, one that maintains end-organ perfu- suspend the solution (“hanging the bag”) from a hook-like sion (i.e., a minimal systolic pressure of approximately 80 device called a hanger. The Paramedic gradually releases the to 90 mmHg), should be established.37,38 A runaway infusion roller clamp, counting the drops in one minute to equal the during trauma resuscitation can adversely affect the patient desired fl ow rate. EMS drug infusion rates are infl uenced by in multiple ways, including increasing intracranial pressure, a number of physical factors which are part of the reality of diluting coagulation factors, and increasing hemorrhagic practice in the fi eld and can alter the drip rate. losses.39 A runaway infusion can be just as devastating for the To control the drip rate, the roller clamp or screw clamp medical patient as well. A runaway infusion can quickly vol- applies pressure against the tubing to offset the pressure within ume overload the patient with kidney or heart failure. Subse- the tubing, thus increasing or decreasing fl ow accordingly. quently, the patient can experience hypertension, pulmonary The pressure within the tubing is a function of the height of edema, or cerebral swelling. the column of fl uid and the diameter of the tubing. Many factors can infl uence the rate of fl ow, such as the Mechanical Flow Control Device friction loss within the tubing, the diameter of the tubing, Paramedics use mechanical fl ow control devices to more the viscosity of the fl uid within the tubing, and the length of the accurately control intravenous fl ow of any drug infusions tubing. Assuming that all these variables remain constant, which are caustic, viscous, or have vasoactive medications. the lone act of raising or lowering an intravenous bag—for Several types of fl ow control devices are available on the example, to go through a door or enter an ambulance—will market. Some work by a venturi effect, controlling the fl ow alter the height of the column of fl uid. Therefore, the pressure by adjusting an aperture, described as dial-a-fl ow devices. within the tubing is affected, and that will in turn change the Others work by placing pressure on the tubing, either through drip rate. This all happens without adjusting the roller clamp. a rotary piston or a linear compression (such as massaging Once a drip rate has been established, it is important to try to fi ngers), and “milking” the tubing at a precise rate. Smaller constantly maintain the intravenous bag at the same height. syringe pumps apply pressure to the plunger in precise pulsa- Even with the best efforts of the Paramedics involved in tions to inject the drug into the fl uid stream. a patient’s care, other factors that cannot be as easily con- The advantage of all of these devices is that they can trolled will infl uence a drip rate. For example, cold fl uids run more accurately control fl ow (Figure 27-23). Many are also through an IV access tend to cause vasospasm in the affected equipped with air-in-line alarms, indicating a break in the vessel. Efforts to warm fl uids can help prevent this occur- rence. However, warming an intravenous fl uid to room tem- perature still means that chilled (less than body temperature) fl uid is being infused. Temperature changes, which are not common in the hos- pital setting, are a fact of life for the Paramedic. Intravenous tubing exposed to cold temperatures, such as occurs when trans- ferring a patient to the ambulance in sub-zero degree weather, will stiffen the IV tubing and alter the tension applied by the roller clamp, as well as change the viscosity of the fl uid within the tubing. Even when the patient is safely secured within the ambulance’s temperature-controlled patient compartment, other factors (such as turbulence at the end of a catheter or slack in an armboard) can cause the IV catheter to migrate up against a valve or the wall of the vein, occluding the fl ow. With all of these variables in mind, it is important that a Paramedic regularly confi rm, and then re-confi rm, the drip rate, particularly if a medicated solution is being infused. Mini- mally, a drip rate should be rechecked after the patient is placed in the ambulance and then upon arrival at the hospital. Prefer- ably, the drip should be checked with every set of vital signs. Out-of-control drip infusions, called runaway infusions, can have serious implications. A runaway infusion of a medicated solution results in the patient being overmedicated. As is the Figure 27-23 Flow control device. 572 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. closed intravenous system, and fl uid empty alarms as well set. The secondary intravenous set would be connected to the as obstruction alarms. The greatest advantage of these fl ow continuous intravenous set, now called the primary infu- control devices may be the margin of safety that they bring sion, via a medication port. If a needle is used to attach the to the less-controlled environment of out-of-hospital emer- two sets, it will be necessary to fi rst cleanse the port with an gency medicine. While not impossible, the risk of a run- alcohol prep pad. away infusion is virtually eliminated by these devices. On With the two administration sets now attached, the pri- the downside, the costs of fl ow control devices, including mary set is placed lower than the secondary set. This is the costs of training Paramedics in their proper use, may be usually accomplished by using a plastic or metal hanger prohibitive. that comes with the secondary administration set. The sec- ondary administration set will now take dominance over Secondary Intravenous Infusions the primary administration as its fl uid column is higher If a continuous infusion is running and an intermittent and thus there is more pressure. When the column of fl uid infusion of a medicated solution is needed, the Paramedic in the secondary administration set equals the level of the can establish a secondary infusion, or piggyback infu- fl uid in the primary administration set’s drip chamber, sion, to the primary infusion. This practice has several then the primary drip will resume fl ow at its previous advantages, including the ability to immediately terminate adjusted rate. the intermittent infusion (e.g., if the patient had |
an aller- gic reaction) and permit a bolus and/or drug to counteract Intravenous Injection any ill effects, such as anaphylaxis-induced hypotension. Use of a secondary intravenous infusion also eliminates Paramedics frequently use IV access as a means for the rapid the need for a second IV access and the accompanying dif- injection of IV medications during an emergency. Early inser- fi culty, and time, of preparing and establishing an intermit- tion of an intravenous access device during patient care pro- tent infusion device (saline lock) which would normally be vides Paramedics a nearly instant ability to administer drugs necessary. directly into the circulation and to target organs. After assessing to ensure that the primary infusion is run- If the IV access site has an intermittent infusion ning and that the IV access is patent, the Paramedic would device attached, then the Paramedic would attach a syringe prepare the secondary IV. Special secondary administration and withdraw about 10 mL of fl uid from the device and sets which have a shorter length are available (Figure 27-24). discard the waste into an approved sharps container. The The secondary set would be run out as per the procedure Paramedic would then attach another syringe, either fi lled described previously for a continuous infusion administration or prefi lled with the medication, to the infusion device and inject the medication. This process is called IV push. Note that if a needle is used then the self-sealing membrane of the injection port must be cleansed. Immediately after injecting the medication, the device is fl ushed with 10 to 20 mL of NSS to clear the medication from the device and assure that all of the medication goes into the circulation (Figure 27-25). Figure 27-24 Secondary intravenous administration set. Figure 27-25 Saline fl ush with prefi lled syringe. Intravenous Access 573 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. If the IV access site has a continuous infusion in place, then the Paramedic would fi rst clamp the tubing, using the roller clamp or slide clamp, and then attach the syringe or prefi lled ampoule, as just described. Once the IV push is completed, the Paramedic may elect to fl ush the tubing with 20 mL of NSS and then unclamp the line. He may also choose to unclamp the line and allow a free fl ow of fl uid to fl ush the IV line for approximately one minute, then re-adjust the fl ow rate. If the patient is in cardiovascular collapse, then the patient’s arm should be raised to help the medication drain out of the limb. Similarly, if the patient is in cardiac arrest, then the limb should be raised and a minimum of one minute of external chest compressions performed to ensure that the drug is circulated. In every case it is important that the Paramedic observe the IV access site for swelling, pain, and other signs of infi l- tration while injecting the medication. Some Paramedics purposefully place the medication port proximal to the IV access site so that the IV insertion site can be observed. If an infi ltration is suspected, then the IV push is stopped and measures taken to counteract the effects of any medication that has leaked into the subcutaneous tissue. It is important Figure 27-26 Flashback of blood verifi es venous to report any intravenous infi ltration. If unchecked, some competency. medications (for example, 50% dextrose) can cause severe local tissue necrosis with the potential for subsequent tendon, constrictive. The distal circulation, sensation, and movement muscle, and nerve damage. should be checked periodically thereafter. An obstructed IV catheter should never be forcibly Obstruction of Intravenous Flow injected with solution (IV fl ush) to remove any obstruc- tions. The risk of forcing a thrombus into the circulation is The fl ow of an IV may slow, or even stop, for a number of rea- not equal to the benefi t of having an intravenous access. The sons. Before removing the IV catheter, the Paramedic should Paramedic should consider removing the suspect IV catheter assess the situation for correctable errors. Starting at the solu- and re-establishing a new IV access. tion bag, the Paramedic would methodically inspect the entire intravenous apparatus. For example, fl ow will stop if the solu- Complications of Intravenous tion bag is empty, a clamp has slipped, or the tubing is kinked. After assessing the administration set and determining that Infusions it is clear of mechanical obstructions, the Paramedic would Despite the best efforts of Paramedics, local or systemic then turn his attention to the IV access site. complications can occur as a direct result of an IV access An infi ltrated IV access site will eventually slow or stop or infusion. An attentive Paramedic can usually detect these an infusion. If the IV access site is infi ltrated, then the IV complications and mitigate the circumstances in order to catheter must be removed immediately (this process is dis- reduce the harm to the patient. cussed later in the chapter). Finding no visible obstructions Arteries and nerves tend to be bundled with veins, par- or infi ltration, the Paramedic may elect to see if there is a ticularly deep veins. Therefore, they are at risk for accidental return of blood, called a fl ashback, when the solution bag needle puncture. An unintentional arterial puncture would be is lowered below the level of the patient’s heart. A fl ashback recognized if the Paramedic noticed a pulsating column of (Figure 27-26) indicates that the IV access remains patent. blood within the fl uid column. However, recognition of an Some IV catheters are positional, meaning that the cath- arterial puncture is more diffi cult in zero fl ow states, such eter lodged up against the wall of a vein or a valve and the IV as cardiac arrest. Careful attention to anatomy, noting the fl ow has been obstructed. To correct a positional IV catheter, location of proximal arteries by their pulse points, can help the Paramedic may elect to withdraw the needle slightly. This decrease the incidence of accidental arterial puncture. process includes breaking the dressing down or raising the A nerve can also be accidentally punctured during an IV hub of the IV catheter off the skin with a gauze pad. If the insertion attempt. Patients usually alert the Paramedic imme- IV access is in a joint, it is advisable to place the joint onto a diately following an accidental nerve puncture. The patient padded splint. If a padded splint is used, then distal circula- will complain loudly of shooting pain, numbness, and tingling tion, sensation, and movement should be assessed before and in the affected limb. Immediate withdrawal of the offending after the splint’s application to ensure that the splint is not needle should provide the patient with immediate relief. 574 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Immediately following successful cannulation of a vein Signs of thrombophlebitis include warmth in the area, by an IV catheter, and frequently thereafter, the Paramedic pain upon palpation, and reddened and swollen tissues. As should assess the IV access for signs of infi ltration or infec- the infection progresses, the infection can advance up the tion. Infi ltration can occur by several mechanisms puncture of vein, creating a visible red trail along the course of the vein the posterior wall, enlargement of the initial incision site, or and pain along the vein’s length. displacement of the catheter. Regardless of the mechanism, While a Paramedic may rarely see a thrombophle- the IV solution seeps into the interstitial fl uid compartment bitis related to a fresh IV, Paramedics may be witness to a (ICF) (i.e., the third space). The resultant swelling can create pyrogenic reaction, a devastating systemic complication increased pressure within a compartment, which can lead to of intravenous therapy. A pyrogenic reaction occurs when impingement of nerves, muscle damage, and compression of a contaminated fl uid, or fl uid run through a contaminated blood vessels (compartment syndrome). administration set, is infused and leads to nearly immedi- One of the earliest signs of infi ltration can be a slow infusion. ate sepsis. Symptoms of a pyrogenic reaction usually occur Other signs of infi ltration include local edema, complaints of within 30 minutes of the initiation of the infusion and include pain at the site, and localized cooling of the skin (Figure 27-27). complaints of headache, chills, and backache. Signs that will An infi ltration of an unmedicated solution should be treated by accompany a pyrogenic reaction include fever, tachycardia, immediate removal of the catheter and application of a warm and, in severe cases, cardiovascular collapse. Examination of compress to the site. Any infi ltration of medicated solutions the solution for contaminants as well as verifi cation of the should be reported and treated immediately. expiration date can help reduce the incidence of pyrogenic Occasionally IV sites become infected. While a Para- reaction (Figure 27-28). medic would not see an infection of an IV site from a recently If a pyrogenic reaction is suspected, the Paramedic should placed IV, patients receiving at-home intermittent intravenous immediately discontinue the infusion. The administration set infusions with temporary indwelling intravenous catheters and intravenous solution should be retained for microbiological and those who are discharged home after a short hospital examination and the lot numbers of the solution recorded on the stay may have signs of an infection at the insertion site. An patient care report. Fortunately, with the advent of disposable infection at the insertion site is called a thrombophlebitis. single-use administration sets and tightly controlled manufactur- An IV access site is essentially a puncture wound, and the ing processes, the number of pyrogenic reactions is very low. body responds to an IV cannulation as it would any wound. Another potentially devastating complication of intra- A thrombus is formed at the wound and the injury healing venous infusions is volume overload. A volume overload process begins. However, the catheter keeps the wound open. occurs when a positional IV access is inadvertently adjusted Bacteria tends to track into the wound, by capillary action, and the infusion fl ow is unrestricted. It can also occur when and the area becomes infl amed.40–42 a clamp is released (e.g., to administer a fl uid bolus) and the infusion rate is not re-adjusted. The symptoms of a volume overload include a nonpro- ductive cough, wheezing, and complaints of shortness of breath or headache. Accompanying signs of volume overload include hypertension, marked jugular venous distention, and crackles in the lung fi elds that are indicative of pulmonary Figure 27-28 Grossly contaminated solution Figure 27-27 Infi ltration of medication at (on the right), as compared with clean solution intravenous site. (on the left). Intravenous Access 575 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. edema. Initially, the Paramedic should reduce the infusion to gloved nondominant hand. With the gloved dominant hand, KVO/TKO or consider using an intermittent infusion device the Paramedic would gently apply traction to the catheter’s (a saline well). Prehospital care of the patient with a sus- hub in the opposite direction of the insertion. With the entire pected volume overload centers on symptomatic relief and length of the |
catheter out of the vein, the Paramedic would supportive care. continue to apply direct pressure to the wound and elevate the Another serious complication of intravenous infusions is limb. If the IV access was in the antecubital fossa, the patient an air embolism. An air embolism can occur when the Para- should be encouraged to keep the limb straight and elevate it. medic fails to run fl uid through an intravenous administration Bending the elbow will widen the opening created by the IV set to fl ush the line prior to use. Symptoms of air embolism catheter and thus increase bleeding. The catheter and admin- include chest pain and lightheadedness. Signs of air embo- istration set should be discarded safely in a biohazard bag and lism include cyanosis, as well as hypotension which can, in a notation made of the removal of the IV access, including the severe cases, lead to cardiovascular collapse. If an air embo- exact location of the access site. lism is suspected, the infusion should be stopped. The patient should then be placed in the left lateral recumbent position, with the right lung superior and the feet elevated above the Intraosseous Access level of the heart. The Paramedic should provide supportive Before the invention of the plastic IV catheter, venous access care and contact medical control for further instructions. was obtained using large metal needles, needles that would be resharpened, sterilized, and reused again and again. These Infusion-Induced Hypothermia large gauge needles often made venous access in the elderly or the vasculopathic patient diffi cult to obtain and alterna- An all too common complication of intravenous infusions tives were sought to peripheral venous access. is hypothermia. The infusion of large quantities of room- In 1922, Dr. C.K. Drinker, of Harvard University, dem- temperature solutions will rapidly cool the body and lead to hypothermia.43,44 onstrated that the use of metal needles inserted into the bone If it is necessary to infuse large quantities marrow of the sternum (intraosseous (IO)) could provide of solutions, then consideration should be given to provid- venous access to the circulation. Dr. Drinker confi rmed that ing a warming blanket (hypothermia blanket) or other similar these intraosseous infusions rapidly infused into the bone device. Some Paramedics use commercially available blood marrow and then later into the central venous circulation. warmers, special heated compartments or thermal sleeves to Later, Dr. Tocantins and Dr. O’Neill expanded on ster- warm the intravenous fl uids prior to administration. Abbott nal intraosseous access sites and included the long bones Corporation, a major supplier of intravenous solutions, rec- (tibia and femur). With multiple sites readily available, and ommends the use of a “conventional warm air oven” which the invention of the bone needle for intraosseous access, IO warms the fl uids before administration. Once the fl uids are access became practical and convenient. During the 1940s removed from the oven, they should be used within 24 hours and 1950s, IO infusion in critically ill patients became some- and not re-warmed again. what commonplace and was used by military medics in World The use of microwave ovens to warm intravenous solutions War II in over 4,000 documented cases. is commonly practiced in emergency departments and operat- However, with the advent of plastic catheters and ing rooms. Caution should be used when microwave ovens are improved venous catheter technology, IO use saw a decline used to warm intravenous solutions because microwave ovens after World War II and remained an historic relic of past med- can create “hotspots” of fl uid within the solution that, during ical practice until 1984. In 1984, Dr. Orlowski, after witness- infusion, could scald the epithelial (inner) lining of the vein. ing IO use in children affl icted with cholera in India, wrote an The use of warm water baths is also not recommended. article in the American Journal of Diseases in Children citing Water from the warm water bath may cross the plastic fl exible the advantages of IO in pediatrics. IO infusion was reborn for container wall and contaminate the solution. Such contami- pediatrics and is now commonplace. Pediatric IO is discussed nation could lead to a potential pyrogenic reaction. in detail at the end of the chapter. Removing Intravenous Access More recently, due to a growing population of aged patients, vasculopathic patients, and emerging new medical Paramedics may be called upon to remove, or discontinue technologies that hold promise for use in the fi eld, the need (DC), an intravenous infusion. A careful step-by-step proce- for venous access has grown more acute. Therefore, the inter- dure will minimize pain for the patient and the potential of est in IO infusion for adults has been revisited. contamination to the Paramedic. The fi rst step is to clamp the administration set and stop the infusion. With the infu- Anatomy and Physiology sion stopped, the Paramedic should gently loosen any tape that is securing the IV catheter. An alcohol prep pad can be of the Long Bones used to undermine the tape’s adhesive. With the tape loose, A long bone has two ends (the epiphyses) and a shaft (the dia- the Paramedic would then place a small gauze pad over the physis). Within the shaft of the bone or the medullary cavity is insertion site and apply gentle downward pressure with the the bone marrow. At the ends of the bones, within the epiphysis, 576 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. is the soft, sponge-like cancellous bone. Together the medullary on the device and the manufacturer’s recommendations, an space and the cancellous bone make up the intraosseous space. IO needle can be placed in the sternum, the tibia, the femur, The IO space contains a complex network of blood ves- or the humerus. Next, the exact point of placement must be sels that connect to the major veins of the central circulation identifi ed, often using adjunct landmarks, and properly pre- via a series of longitudinal Haversian canals that exit the bone pared with povidone-iodine or similar antiseptic (Skill 27-3). and connect directly into the major veins. Infusing fl uids into For a step-by-step demonstration of Intraosseous the intraosseous space ultimately infuses fl uids into the cen- Access, please refer to Skill 27-3 on pages 589–590. tral veins via these Haversian canals. After inserting the needle, following the manufacturer’s Intraosseous Devices recommendations, the needle should be fl ushed with 5 to 10 cc of sterile saline to ensure patency. If the patient is con- A number of IO devices are presently on the market. These scious, an additional bolus of lidocaine (approximately 10 cc) devices range from manually inserted IO needles, the type can help to reduce the pain of infusion. used primarily in children, to medical drills that create a pre- cise opening for insertion of an IO needle. Because of the large number of IO devices on the market, Paramedics are advised to read the accompanying medical literature that Street Smart comes with each device and to familiarize themselves with the device by practicing on a manikin or model before trying to utilize the IO in the fi eld. Improper placement of an IO needle in an obese patient can be avoided if the Paramedic monitors the Indications and Contraindications insertion. If bone resistance cannot be felt once the There are several indications for adult IO placement. One needle has been placed to a depth of approximately indication is cardiac arrest.45, 46 During cardiac arrest, the 5 cm, indicated by a black band on some IO needles, cardiovascular system is in collapse and venous access can then the needle should be withdrawn and an be a challenge. Intravenous access can be diffi cult to obtain or is obtained at a cost of prolonged scene times. The rigid alternative site prepared. container of the IO, the bone, provides a ready access even during zero blood fl ow states. Other indications include any time there is a need for an immediate access for medication Medication Administration administration for the patient in extremis. The majority of prehospital medications can be administered Advantages of IO access are also several-fold. IO access via the IO route (Table 27-1). The exceptions to IO admin- is rapid, quicker than IV access in many cases, and generally istration include 9% saline, also known as super saline, and requires less skill and training to master. In one study, IO adenosine. access was able to be obtained in the fi eld within 20 seconds This list includes medications typically used during or less with a 97% success rate.47–50 a cardiac arrest. Considering the speed of attaining thera- However, IO insertion is not without its risks. IO insertion peutic levels of these drugs via the IO route, IO is consid- can be painful in conscious patients, although that is not always ered by most authorities to be preferable over endotracheal the case. Some patients have compared the pain of an IO inser- administration. tion to the discomfort of a large bore IV. IO infusions can also be painful, but with a bolus of lidocaine can further reduce the pain Phlebotomy of infusion. Finally, the IO has a potentially higher risk of osteo- myelitis. However, the incidence of osteomyelitis is uncommon. A sample of the patient’s blood, for laboratory analysis, may It has been reported that the osteomyelitis rate for IO infusions be drawn at the time that the IV access is obtained. However, is about one in 200 cases. Other attendant risks include fat embolism, fracture, extravasation, and compartment syndrome. Table 27-1 List of IO Medications It should be noted that these complications are rare and can usu- ally be prevented by careful insertion and monitoring. • Amiodarone • Furosemide The single largest drawback to IO may be the inability to • Atropine • Lidocaine infuse large bolus of fl uids. The IO infusion is generally similar • Dextrose 50% • Naxolone to that of a 20 gauge IV catheter.51 The addition of a pressure • Diazepam • Rocuronium infusion bag enhances fl ow rates to more acceptable levels. • Dopamine • Succinylcholine • Epinephrine • Vasopressin Intraosseous Placement • Etomidate • Vecoronium Preparation of the IO site is similar to preparation for an IV • Fentanyl • Versed insertion. First the Paramedic needs to select a site. Depending Intravenous Access 577 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. there are times when a blood sample is required but IV access then advanced, bevel up, into the skin and then the vein, at is not necessary. In this case, a Paramedic would perform a about a 15 to 20 degree angle. Once the Paramedic is con- phlebotomy, drawing blood through a straight needle, to fi dent that the needle is in the vein, then the blood tube is obtain the sample. joined with the sheaved needle inside the barrel and blood is Prior to performing the venipuncture, the Paramedic automatically drawn up. needs to assemble the necessary equipment, including blood After the fi rst fl ash of blood occurs, confi rming place- sample tubes. There are a number of blood sample tubes and ment, the tourniquet is released and the blood tube allowed each has a specifi c purpose. The color of the stopper indicates to fi ll completely. Red-topped tubes should be placed aside a blood tube’s use. The patient’s condition usually dictates while other colored-topped tubes are generally gently inverted which blood tubes will be used and is based upon the expec- approximately 10 times, but not shaken, before being set tation that |