The Head-Injured Patient

Traumatic brain injury (TBI) is the most common cause of mortality in trauma patients. Airway management in this cohort of patients is often performed for airway protection. Given the relatively high incidence of peri-intubation desaturation, hypocapnea, and hypotension in emergency intubations, the benefit of ETI for airway protection to prevent aspiration must be weighed against the risk of the occurrence of physiologic adverse events known to increase morbidity and mortality in TBI patients. If intubating for the purpose of airway protection, it is usually less time sensitive and should not be rushed. Every precaution should be taken to adequately preoxygenate and resuscitate first.

Apnea resulting from head injury requires immediate intervention. There are 3 mechanisms by which apnea may occur in TBI:

• 1.
  

  Severe or catastrophic brain injury

  
  
• 2.
  

  Impact brain apnea (IBA)

  
  
• 3.
  

  Loss of consciousness with resultant functional airway obstruction

Severe or catastrophic brain injury is usually nonsurvivable, and associated with early death. Predictions of outcome are usually not made until the patient has undergone a full trauma resuscitation, which often includes ETI. Contrastingly, IBA and functional airway obstruction may be correctable with simple airway opening maneuvers, with or without brief ventilation support. IBA from head trauma results in a primary respiratory arrest without significant parenchymal injury to the brain. In contrast to patients with head injury with functional airway obstruction, patients with IBA do not respond to simple airway opening maneuvers alone, and may require brief ventilation support to prevent secondary hypoxic insult. With appropriate treatment, prognosis is generally good.

Head-injured patients with a decreased level of consciousness frequently receive prehospital advanced airway management. In one series, 30% to 40% of patients are assessed as having partial or complete airway obstruction on EMS arrival. A proportion of these patients will respond to basic maneuvers, and those who do not usually have more severe, less survivable injuries. This observation in part explains the comparatively poor survival rates for trauma patients who are intubated in the prehospital setting

Airway Management in Patients with Suspected Cervical Spine Injuries

Trauma resuscitations typically proceed under the assumption that the patient has an unstable cervical spine (c-spine) injury until proven otherwise. In the prehospital environment, trauma patients are often placed in a cervical spine collar and secured to a rigid backboard with blocks. Although a long-standing tradition in emergency medicine and trauma care, there is very limited published evidence to support the notion that cervical spine collars and immobilization prevent secondary spinal cord injury. Although the incidence of c-spine injuries is relatively low (occurring in approximately 2% in the general trauma population and 6%–8% in patients with head and facial trauma), practitioners often operate with deep concern that intubation may cause secondary spinal cord injury, making it one of the most frequently encountered reasons for difficulty in trauma airway management.

A frequently studied outcome is the amount of translational or angular movement of the cervical spine caused by airway manipulation. Although it appears that spinal movement occurs to a variable degree depending on the airway technique used, it is unclear whether or not this results in any important differences in clinical outcomes. In cadaveric studies of unstable c-spine injuries, movement occurring with both direct laryngoscopy (DL) and indirect laryngoscopy do not significantly exceed the physiologic values observed with intact spines. Despite the need to be cautious, even in patients with known cervical spine injuries, secondary neurologic deterioration is rare, with a reported incidence of 0.03%.

Trauma patients with suspected spinal injury are typically fully supine, inhibiting the practitioner’s ability to optimally position the patient for DL. Manual inline stabilization (MILS) worsens the view obtained with DL in up to 50% of cases. Minimizing challenges with laryngoscopy and intubation mandates proper application of MILS, whereby the provider tasked with this role immobilizes the head and neck without immobilizing the mandible ( Fig. 1 ). C-spine collars and improperly applied MILS will restrict mouth opening and tongue and mandibular displacement required for optimal laryngoscopy. Despite properly applied MILS, the provider should still expect a higher occurrence of a poor view with DL, longer intubation times, and more frequent failed intubation attempts. This scenario is often easily managed by applying external laryngeal manipulation or use of a bougie.

( A ) MILS applied incorrectly limiting mandibular range of motion (ROM). ( B ) MILS applied correctly with hands over the ears (ear-muff approach) not limiting mandibular ROM.

Another theoretic concern is that application of MILS results in the need for an increased applied force during laryngoscopy, which paradoxically may lead to more movement during intubation than occurs without MILS. Recognizing our inability to correct the fundamental geometric challenge of DL, the provider may opt to use a “look-around-the-corner” indirect device, such as a video laryngoscope with a hyperangulated blade. The 3 classes of video laryngoscopes are described in Box 1 .

It would seem intuitive that because indirect hyperangulated video laryngoscopy (VL) consistently provides an improved glottic view and that c-spine immobilization consistently impairs the glottic view with DL, that VL is the better choice for trauma patients. However, having a good view with VL does not mean that easy ETI will follow. When using a hyperangulated video laryngoscope, a deliberate restricted view may be desired to facilitate the often seemingly frustrating paradox of having a great view of the glottis but not being able to deliver the ETT.

Literature comparing intubation devices in c-spine immobilized patients has yielded inconsistent findings, and no consensus as to the optimal approach. A recent meta-analysis by Suppan and colleagues reported more failed intubations for DL compared with several alternative intubating devices in patients with c-spine immobilization. Although the investigators acknowledge the weaknesses of available literature, they note there was no statistically significant difference in first-attempt success between the more commonly used VL devices (GlideScope, C-MAC) and DL. It is less likely that there is a “the right device” for the unstable c-spine and more important is the right experienced practitioner, using a device with which he or she is the most comfortable.

Airway management in the patient with a possible c-spine injury must strike a balance between minimizing movement and the need to quickly and successfully intubate on first attempt, thereby minimizing the harm of hypoxemia that may be associated with multiple attempts at intubation. It seems reasonable to consider that if the patient’s spinal cord has survived the massive forces of the crash, as well as repositioning during extrication and immobilization, that the chances that movement occurring during controlled airway management will result in cord injury is extremely low. As suggested by Aprahamian and colleagues, the primary benefit of a rigid cervical collar is to serve as a reminder about the potential existence of an unstable c-spine injury

The Contaminated Airway

The presence of airway contamination with either blood or vomitus has been shown to decrease the rate of first-attempt intubation success, regardless of the device used. Blood and vomit in the airway can lead to early and late complications related to difficult airway management and/or aspiration. The bloody airway is not uncommon in trauma patients with injuries to the face and/or neck and may range in severity from scant bleeding, which is easily managed, to significant hemorrhage. The combination of altered levels of consciousness, diminished protective airway reflexes, delayed gastric emptying, and full stomachs place trauma patients at high risk of vomiting and aspiration during airway management. Management of contaminated airway must begin with the expectation that the degree of blood, vomit, and secretions appreciated externally represents only a fraction of what may be encountered on initiation of an RSI. As such, providers must ensure that adequate suction is available (at least 2 large rigid suction catheters). Consideration must be given to positioning, placing the patient in reverse Trendelenburg or, if safe to do so, seated upright or even leaning forward to allow drainage of blood and secretions. For c-spine immobilized patients, suction must be immediately within reach, and restraints securing the patient to the bed should be avoided. During the preoxygenation phase, positive-pressure ventilation (PPV) should be used only if necessary balanced against the patient’s oxygenation status, as ventilatory pressures of 20 cm H2O or more are likely to ventilate the stomach, increasing the risk of regurgitation and aspiration.

When blood or vomitus is overwhelming suction capabilities, the provider may place either one rigid suction or an ETT in the upper esophagus to divert the offending contaminants. The ETT or rigid suction may then be stabilized to the left of the laryngoscope and the second suction used during laryngoscopy in search of the epiglottis ( Fig. 2 ). Often the epiglottis may be “lifted” (more easily accomplished in a reverse Trendelenburg) out of the contaminant during laryngoscopy, providing an anatomic reference for placing a bougie.

Suction in upper esophagus stabilized to left of laryngoscope (SALAD approach).

( Courtesy of Ruben Strayer, MD.)

Most of the literature comparing DL with VL in the bloody or vomitus-filled airway is simulation-based, and concern exists about the vulnerability of VL camera lens in the contaminated airway. Recently, Sakles and colleagues retrospectively reviewed more than 4600 intubations and demonstrated that, although airway contamination was associated with a decreased first-attempt success rate, this was irrespective of the choice of GlideScope or DL as the first-attempt device used. The use of DL or Macintosh VL, in which a direct approach can be used if the camera is obscured with the aid of a bougie, may be preferred approaches.

Although not studied in a clinical setting, the Ducanto suction-assisted laryngoscopy airway decontamination (SALAD) approach has gained acceptance as a method to manage the soiled airway. In the uncommon circumstance in which blood or vomit is overwhelming these management strategies, intubation is not possible and the patient is critically desaturating, rescue oxygenation with a BVM (bag-valve-mask) or SGA (supraglottic airway) is unlikely to work and an FONA approach is indicated

The Uncooperative or Agitated Patient

Uncooperative, violent, or agitated patients can encumber adequate assessment, leading to missed injuries and inadequate resuscitation. Agitation can be multifactorial and may be the result of head injury, hypoperfusion, hypoxemia, or intoxication. It may not be clear why a patient is agitated and providers must determine if the patient is agitated AND injured or agitated BECAUSE the patient is injured.

The EAST guidelines recommend that aggressive behavior refractory to initial pharmacologic intervention is a discretionary indication for intubation; specifically that if a patient’s level of agitation prevents assessment and resuscitation, intubation and sedation should follow. Sise and colleagues reviewed 1078 trauma patients intubated for discretionary indications (eg, agitation, alcohol intoxication) and found that 62% of patients, once investigated, had a significant head injury. Importantly, there was no significant difference in complications associated with acute airway management in patients intubated for discretionary indications, as compared with those intubated for higher acuity reasons.

In severely agitated patients, RSI is at times undertaken before optimal hemodynamic resuscitation and preoxygenation has been achieved. Patients rendered apneic as part of an RSI without adequate preoxygenation are at high risk of desaturation. The use of ketamine to facilitate cooperation and allow interventions including preoxygenation has been described as “delayed-sequence intubation” by Weingart and colleagues. If given slowly, a dissociative intravenous dose of 1 to 1.5 mg/kg poses little risk of respiratory depression. However, the use of any sedative, particularly in the presence of other intoxicating ingestions, may inhibit airway reflexes. Concerns that ketamine may raise intracranial pressure and worsen outcomes in TBI is not supported by evidence

Maxillofacial Injuries

Maxillofacial fractures may present dramatically and affect airway management in one of several ways. Posterior displacement from fractured maxillofacial segments may cause soft tissue collapse and occlude the airway, which may be worsened by the presence of c-spine collar. Bleeding may be significant and cause airway management challenges, as previously discussed. In the supine position, the pooling of blood in the oropharynx may stimulate a gag response or vomiting, which in turn may worsen bleeding. Although patients with mandibular fractures in 2 or more locations may be easier to intubate due to increased mobility of the mandible and attached soft tissues, associated condylar fractures may cause a mechanical obstruction limiting mouth opening, making laryngoscopy and intubation difficult. Maxillofacial fractures may also cause trismus that may resolve with the neuromuscular blockade; however, differentiating this from a mechanical obstruction before intubation is required and is often difficult.

Airway management begins with careful consideration to patient positioning. Awake, neurologically intact patients without neck pain should be allowed to position themselves however they are most comfortable to control tissue obstruction and allow drainage of blood and secretions. They may be given a rigid suction catheter to use themselves, which is more often tolerated, effective, and less likely to stimulate a gag and resultant vomiting. Adherence to protocols requiring rigid spinal immobilization and supine positioning may result in catastrophe.

The provider should presume that preoxygenation in patients with facial trauma may be difficult, and that reoxygenation with mask ventilation during RSI if the first attempt is unsuccessful may be difficult or impossible. Distortion of facial structures may make obtaining a seal with a BVM device difficult and patients may poorly tolerate PPV, as disruption of tissues may result in worsening bleeding and in cases of associated lower airway trauma, significant subcutaneous emphysema. Practitioners must proceed with the assumption that structural collapse of the airway may occur during an RSI.

The choice of approach is based on the patient’s ability to maintain a patent airway and their oxygenation status. For a “have no time” scenario (obstructing and hypoxemic), the primary approach may require a FONA, facilitated by a dissociative ketamine dosing. Alternatively, a “double set-up” may be used: RSI with a single attempt at oral intubation followed immediately by FONA rescue if needed ( Fig. 3 ).

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