Chapter 20. Airway Management in the Emergency Department

An unconscious 19-year-old morbidly obese man is brought into the emergency department (ED) by emergency health services (EHS) paramedics, having been found unresponsive at a fraternity initiation party. He had been drinking heavily, although the amount of alcohol consumed is unknown. The patient is unidentified and there is no available past medical history. Respirations are shallow, and paramedics have inserted a nasal trumpet and an oral airway and are assisting ventilation with a bag-mask. They had attempted oral and nasal intubation three times in the field but failed due to the patient being combative and obesity.

The vital signs are: blood pressure (BP) 114/70 mm Hg, heart rate (HR) 103 beats per minute (bpm), respiratory rate (RR) 8 to 10 breaths per minute and shallow, and oxygen saturation is 92% by assisted bag-mask-ventilation. The patient responds only to pain with purposeful movement. His blow by breath sample for ethanol reads at 220 mg/dL or 47.7 mmol·L−1 and his blood sugar is 90 mg/dL or 5 mmol·L−1. There are no signs of trauma.

In summary, we have no information as to his identity, his history of present or past illnesses, history of allergies or medications, his past medical history, his family or social history, or what or how much might be in his stomach.

20.2.1 What Is It About Managing the Airway in the ED that Makes It "Different"?

Making crucial decisions in the face of incomplete information is fundamental to the practice of emergency medicine. Expert management of the emergency airway is a defining skill of emergency medicine. All necessary equipment and medications, including neuromuscular blocking agents, must be readily available to emergency practitioners who must be skilled in all aspects of airway management. Patients requiring immediate emergency airway management present, sometimes unexpectedly, to the ED. Many of the patients have characteristics associated with difficult laryngoscopy and intubation, but the urgency of the airway problem frequently prevents deferral or even consultation. Frequently, others have already tried and failed to manage the airway, resulting in trauma and other complications which compound the difficulty faced by the next practitioner. Such issues serve to highlight the importance of the verbal report given by field personnel as they deliver patients to an ED.

Accordingly, the emergency practitioner must be both capable and constantly prepared to undertake skilled and timely intervention in patients with compromised airways, and to plan an approach that takes into account all potential difficulties and incorporates within it backup plans (Plan B, Plan C, etc).

20.2.2 Who Is Primarily Responsible for Managing the Airway in the ED?

Airway evaluation and management is the first priority of resuscitation, and establishing a patent airway and oxygenating the brain and vital organs takes precedence over all other activities. That is not to say that concurrent evaluation and management activities should not occur, it simply says "Do this first!" Identifying that the patient requires airway management does not necessarily mandate that the management be undertaken immediately; it simply establishes that early, deliberate airway management is indicated. In some cases, the patient will be apneic with an unprotected airway, and airway management will supersede virtually all other evaluation and management. In other cases, the examining practitioner will identify that early airway management is required, and plan to provide it early during the course of comprehensive and coordinated examination and intervention.

The emergency practitioner has final responsibility for ensuring definitive management of the airway for patients presenting to the ED, which might, at times, require the advice and help of consultants from anesthesia, or, more rarely, otolaryngology, or any of a number of other specialties.

20.2.3 What Are the Indications for Tracheal Intubation in the ED?

The indications for endotracheal intubation in the ED are straightforward:

• Inability of the patient to maintain the airway
• Failure to protect the airway
• Failure to effect adequate gas exchange
• A predictable deterioration in maintaining or possible loss of the airway, including the need for medications that might threaten airway maintenance or ventilation

Early establishment of a patent airway and provision of adequate oxygenation are critical to patient survival. Equally important is the ability to predict an impending loss of airway patency or gas exchange capability, particularly if the patient will be subjected to diagnostic studies in other specialty areas beyond the ED, or transported by land or air to another facility.

Subsequent decisions as to how and when the airway should be managed will depend on numerous factors, including the skills and experience of the practitioner, the equipment available, the condition of the patient, and the anatomy of the airway.

20.2.4 Is There a Conceptual Framework Which the Emergency Practitioner or a Consulting Anesthesiologist Employs in Approaching the Airway in the ED?

It is widely recognized that a conceptual framework focusing on rapid airway evaluation, critical action analysis and performance, and facility with an array of airway management techniques minimizes the risk of failure and improves outcome.1 To be precise, in an emergency, the airway practitioner must be capable of the following:

• Rapidly assessing the urgency of the situation and the patient's need for intervention
• Determining the best method of airway management for the particular circumstances at hand and having at least a backup plan in the event of failure
• Understanding the risks and benefits of each possible approach
• Deciding which pharmacological agents to use, in what order, and in what doses
• Managing the airway in the context of the patient's overall condition
• Using any of a number of airway devices to achieve a definitive airway while minimizing the likelihood, severity, and duration of hypoxemia or hypercarbia
• Recognizing when the planned airway intervention has failed and an alternative (rescue) technique is required
• Being able to rapidly identify when to call for assistance and what type of assistance might be required

20.3.1 How Did Airway Management in the ED Evolve to Where It Is Today?

Emergency airway management for much of history consisted of various forms of back-pressure/arm-lift artificial respiration, or mouth-to-mouth, mouth-to-nose, and bag-mask-ventilation (BMV) by minimally trained providers until the 1960s when resuscitation research identified airway management failure as a crucial issue affecting outcome.2-5 By the early 1970s, endotracheal intubation was recognized as an essential part of the skill set for physicians providing emergency care, but most physicians staffing emergency departments were trainees or practicing physicians with little or no formal training in emergency medicine. Intubation was generally accomplished without neuromuscular blocking agents, using either the oral or the nasal routes, sometimes requiring heavy sedation before airway management could be attempted. Intubation using a sedative, such as a benzodiazepine, often accompanied by an opioid, such as morphine, became a common practice despite its frequent failures and complications.

The advent of emergency medicine residency training programs in 1969 and the rapid growth of the specialty through the ensuing two decades established a large cadre of trained emergency medicine specialists and led to the rapid deployment of neuromuscular blockade to facilitate orotracheal intubation. By the late 1980s, the use of neuromuscular blockade for this purpose was well established in emergency medicine residency training programs, and had been dubbed "rapid sequence intubation" (RSI) in distinction to the anesthesia term "rapid sequence induction."6 By the mid to late 1990s, neuromuscular blockade was widely used and it became evident that neuromuscular blockade not only made the technical task of intubation easier and faster, but also resulted in greater success with lower complication rates.6

However, a need clearly emerged for a consistent framework to identify patients at risk for difficult and possibly failed laryngoscopy and intubation, to develop a reliable approach to such patients, and to expand the rescue options beyond the single choice of cricothyrotomy.

The challenges facing emergency airway practitioners today include:

1. Restricting the use of neuromuscular blockade only to patients in whom there is a strong likelihood that tracheal intubation will be successful or that gas exchange can be maintained by some other technique in the event of failure

2. Selecting an alternative approach for those patients in whom a difficult or impossible intubation may be anticipated

3. Ensuring the success for alternative rescue devices or techniques in the event of intubation failure

20.4.1 How Common Is the Difficult and Failed Airway in the ED?

Difficult airways are common in emergency practice, the incidence being as high as 20% of all emergency intubations. However, the incidence of intubation failure is quite uncommon, being in the 0.5% to 2.5% range. Moreover, the disaster of being unable to intubate or ventilate rarely occurs (0.1%-0.5%).6

It is crucial to realize that in the case of a difficult airway, the same standard applies as for a routine airway: the practitioner must secure the trachea with a cuffed endotracheal tube. In the case of a failed airway, the approach is focused on rescue and in keeping the patient alive and well oxygenated until the airway can be definitively secured.

Thus, the devices, techniques, and even the approach differ in these two situations. A difficult airway is managed in an anticipatory way; a failed airway is managed in a reactive way. In 2002, Walls coined the phrase "The Difficult Airway is something you anticipate; the Failed Airway is something you experience."7

20.4.2 What Is Unique About Airway Management in an ED?

Emergency airway management may be in an ED, or extend beyond the ED to those locations where emergency practitioners are called to manage airway, or to be directly responsible for their management by surrogate providers such as paramedics. These locations include the out-of-hospital setting, in-patient wards, intensive care units, diagnostic units such as x-ray or radiotherapy, and other sites.

Emergency airway management situations are characterized by several unique features:

• Clinical evaluation, rather than blood gases, is used to assess the adequacy of ventilation and judge the need for intubation in the acutely ill patient.
• The patient is usually at high risk for aspiration.
• The airway must be secured by a cuffed endotracheal tube. Canceling the case, awakening the patient, or significantly delaying airway management is not an option, nor in most cases, is any other form of airway management that does not protect the airway (beyond the temporary use of an extraglottic device).
• Crucial decisions must be made on the basis of less information than in almost any other setting. This, in fact, is the essence of emergency medicine and highlights the importance of expeditious and planned strategies for airway evaluation and management (see Chapters 1 and 2 for details).
• The need for intubation is ordinarily obvious, but in an emergency, the decision to intubate is often dependent on having knowledge of the natural course of the disorder or injury rather than on the patient's precise clinical status at the time of the evaluation. There are few other situations in medicine in which judgment and knowledge of the anticipated clinical course of a disorder are so crucial.
• Erring on the side of caution:
  • Intubate earlier rather than later. Be especially cautious of penetrating neck wounds with evidence of injury to the airway itself (subcutaneous air) or the vascular system (hematoma—it does not have to appear to be expanding). Both the presence of such injuries and their apparent time course are important. The patient who presents 12 hours after sustaining a penetrating neck injury has withstood the test of time. A similar-appearing injury 10 minutes after injury is an unknown, and must be assumed to present an imminent risk. "Do not paralyze a patient (ordinarily RSI) if you are not confident that you can oxygenate the patient successfully with a BMV unit or an EGD. If these fail, a surgical airway is required, and this procedure must be planned for. Anticipating this procedure requires assessing the difficulty for each approach to managing the airway prior to embarking on Plan A (see Chapter 2).
  • Do not sit on patients with upper airway obstruction or insist on taking the patient out of the ED (eg, to the CT scan or to the OR) unless it is absolutely clear that the patient's condition is stable enough and you are confident you can successfully secure the airway if needed. Observing the patient presents the risk that anatomy will worsen and obstruction will ensue, at which time the patient will be much more difficult to intubate and the need for doing so will be much greater.

20.4.3 How Should One Proceed in Managing the Airway in an Emergency?

Once it has been decided that intubation is indicated, the focus must be on what kind of airway problem is present, and what the correct course of action is (see Chapter 2).

• Is this a "crash airway" situation in which the patient is unconscious, unresponsive, and near death?
• Is this a "difficult airway" in which one anticipates difficulty with bag-mask-ventilation, EGD use, laryngoscopy and intubation, or cricothyrotomy?
• If neither of these two situations exists, then an RSI is the method of choice.
• Has a failed airway supervened?

This systematic approach to airway management in the ED takes into account all possible presentations, and properly identifying the type of airway situation permits the practitioner to select an appropriate course of action. Algorithms that address these situations are expeditious management strategies often used in crisis and are described in Chapter 2.

Rapid sequence intubation (RSI) by emergency practitioners is associated with a high rate of success and low incidence of complication. However, some patients should not be paralyzed and to successfully manage their airways will require alternative procedures, such as awake bronchoscopic intubation. The current challenge then is how to identify these patients in whom intubation or ventilation with bag-mask or extraglottic devices would not suffice.

In the case presented here, the emergency practitioner recognized multiple difficult airway indicators, including obesity, a large tongue, and a high larynx. Because the patient was adequately oxygenating via the bag-mask, and after assessment determined that there was not significant bleeding in the airway caused by the failed earlier intubation attempts, the patient received topical anesthesia with lidocaine (see Chapter 3) and underwent uneventful nasal intubation using a flexible bronchoscope. The patient did not require sedation, was ventilated for 2 hours, then weaned to a T-piece. He was extubated 12 hours after presentation and discharged home after evaluation by an alcohol-abuse counselor.