Here, the very condition that mandates intubation may also render it much more difficult and prone to failure. Direct airway injury may be the result of

In cases of distorted anatomy, the approach must be one that minimizes the potential for catastrophic deterioration. Airway disruption may be marginal or significant, real or potential. In either case, the guiding principle is to secure the threatened airway early, while more options are preserved, and the patient’s stability permits a more deliberate approach. Careful decisions guided by the airway algorithms will need to be made about the use (or not) of neuromuscular blockade, the primary method of airway management, and the airway rescue plan. The importance of mobilizing resources (equipment and personnel), strong leadership, and effective communication with the entire team cannot be overemphasized.

As for any other anatomically distorted airway, application of the difficult airway algorithm will often lead to a decision to perform an awake intubation. In patients with signs of significant airway compromise (e.g., stridor, respiratory distress, and voice distortion), both the urgency of the intubation and the risk of using neuromuscular blockade are high. When symptoms are more modest, there is more time to plan and execute the airway intervention, but in neither case is delay advisable. The patient’s oxygenation should be assessed (i.e., “Is there time?”), and it should be determined if RSI is advisable, possibly under a double setup, even though the airway is difficult (see Chapter 3). This will depend on the clinician’s confidence about the likelihood of success of oxygenation using a bag and mask or an EGD, and intubation by direct or video laryngoscopy. Often, an airway not amenable to direct laryngoscope can be managed using a video laryngoscope. When airway management is required immediately, RSI (preferably using a video laryngoscope) with a double setup may be used, but when time permits and the airway is not obscured by blood, the best approach often is awake intubation using a flexible endoscope technique with sedation and topical anesthesia (see Chapter 15). This permits both examination of the airway and careful navigation through the injured area, even when the airway itself has been violated. This is especially true if a tracheal injury is suspected, as no other method of intubation allows the airway to be visualized both above and below the glottis. When the airway is disrupted, the endotracheal tube used should be as small as is reasonable to maximize the likelihood of success and to minimize the likelihood of additional airway injury.

Smoke inhalation can present on a spectrum from mild exposure to complete airway obstruction and death. The initial assessment is designed to identify the presence or absence of high-risk historical features (e.g., closed space fire) and physical findings (e.g., singed nasal hairs, perinasal or perioral soot, carbon deposits on the tongue, hoarse voice, and carbonaceous sputum). When evidence of significant smoke inhalation is present, direct examination of the airway, often with intubation, is important. This is best done with flexible endoscopy, which permits evaluation of the airway and immediate progression to intubation, if indicated. Supraglottic edema is an indication for intubation, even if the edema is mild, because progression can be both rapid and occult. Observation in lieu of airway examination can be hazardous because the airway edema can worsen significantly without any external evidence, and by the time the severity of the situation is apparent, intubation is both immediately required and extremely difficult or impossible. If examination of the upper airway identifies that the injury is confined to the mouth and nose, and the supraglottic area is spared (normal), then intubation safely can be deferred, with subsequent examination at the discretion of the operator. If it is unclear whether edema is present, it is useful to periodically perform a repeated upper airway examination (e.g., 30 to 60 minutes), even if symptoms or signs do not develop or worsen.

In the NEAR studies, head injury is the most common indication for emergency department trauma airway management. Traumatic brain injury (TBI) is the number one cause of injuryrelated death worldwide. The principles of management of the patient with TBI and elevated intracranial pressure are discussed in more detail in Chapter 32.

When neurologic status is altered, whether by traumatic brain injury, spinal injury, or both, a rapid, but thorough neurologic examination is important before intubation is undertaken, so that baseline neurologic status is documented to guide subsequent assessments and therapeutic decisions. Airway management decisions in the patient with severe TBI are centered around the prevention of secondary injury, that is, minimizing the magnitude and duration of hypoxia or
hypotension. Secondary injury is the term applied when the insult to the injured brain is worsened by hypoxia, hypotension, or both.

Concrete steps can be taken to reduce the risk of secondary injury before, during, and after airway management:

First—Bring the principles of secondary brain injury prevention to the field. EMS providers should be educated and equipped to begin neuroresuscitation before the patient arrives in the ED. Maintenance of adequate perfusion pressure (mean arterial blood pressure) and oxyhemoglobin saturation are the keys.

Second—Optimize brain perfusion before intubation, if possible. Appropriate volume replacement with normal saline solution may mitigate or prevent hypotension caused by RSI drugs or positive-pressure ventilation.

Third—Don’t delay. Often, fentanyl and lidocaine are given as pretreatment agents for patients with elevated intracranial pressure (see Chapters 19, 20, and 32). If the patient is hypoxic because of hypoventilation or lung injury, intubation should not be delayed for administration of these pretreatment drugs. Similarly, if respirations are depressed, fentanyl should be avoided. Often, despite the presence of known or suspected elevated intracranial pressure, conflicting clinical considerations argue for a simple approach, such as rapid RSI using etomidate and succinylcholine. However, it is precisely the brain injured patient who has the most to gain by mitigating the adverse physiologic responses to intubation, especially the very young who are endowed with the greatest potential for recovery.

Fourth—Select induction agents and doses carefully. Etomidate, because of its balance of preservation of hemodynamics and modest cerebroprotective properties, is frequently the agent of choice. The dose should be reduced from 0.3 mg per kg to 0.¹⁵ to “0.2” mg per kg in the face of compensated or decompensated hypovolemic shock. If the patient is severely compromised, ketamine, if available, is the agent of choice. The dose of ketamine is reduced to 0.5 mg per kg if the patient is in shock. The historical dogma that ketamine causes a clinically meaningful rise in intracranial pressure (ICP) is not evidence based. However, ketamine may raise the systemic blood pressure, so it probably should be avoided in head injured patients who are hypertensive.

Fifth—Avoid hyperventilation. Once felt to be a basic tool in the management of severe TBI, the use of hyperventilation is now known to lead to poorer outcomes. There is no question that hyperventilation transiently reduces intracranial pressure (ICP). It does so, however, by reducing CNS perfusion, violating the central tenant of secondary injury prevention.

Severely injured blunt trauma patients are assumed to have cervical spine injury until proven otherwise, and require in-line stabilization during airway management. Although in-line stabilization is believed to help protect against spinal cord injury during intubation, it can create several problems as well. Intoxicated or head injured patients typically become agitated and difficult to control when strapped down on a backboard. Physical and chemical restraint may be required. Aspiration is a significant risk in the supine patient with traumatic brain injury or if they are vomiting. In the supine position, ventilation may be impaired, particularly for obese patients, and chest injury may make matters even worse. High-flow oxygen should be provided to all patients, and suction must be immediately available.