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  Rapid-sequence intubation (RSI) is the preferred method for endotracheal tube placement in the emergency department.

  
  
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  The decision to intubate should always be made on clinical grounds. Time permitting, assess for factors predictive of a difficult airway before RSI.

  
  
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  General criteria for endotracheal intubation include a failure to protect the airway, a failure to adequately oxygenate, and a failure to expire accumulating CO₂.

  
  
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  Pursue alternative techniques (eg, cricothyrotomy) in patients when the initial airway intervention has failed and the patient cannot be adequately ventilated.

Successful airway management depends on the prompt recognition of an inadequate airway, the identification of risk factors that may impair successful bag-valve-mask (BVM) ventilation or endotracheal tube (ETT) placement, and the use of an appropriate technique to properly secure the airway. The decision to intubate is a clinical one and should be based on the presence of any 1 of 3 major conditions: an inability to successfully protect one’s airway against aspiration/occlusion, an inability to successfully oxygenate the blood (hypoxemia), or an inability to successfully clear the respiratory byproducts of cellular metabolism (hypercapnia). Additional indications including the desire to decrease the work of breathing (sepsis), the need for therapeutic hyperventilation (increased intracranial pressure [ICP]), and the need to obtain diagnostic imaging in noncooperative individuals (altered mental status) should be taken into account on a patient-by-patient basis.

Techniques for the management of unstable airways range from basic shifts in patient positioning to invasive surgical intervention. Standard basic life support recommendations such as the head-tilt chin-lift maneuver may open a previously occluded airway. Oropharyngeal and nasal airway adjuncts are both simple to use and highly effective in this setting, but are unfortunately often underutilized. Failure to respond to these measures warrants the placement of an ETT. Rapid-sequence intubation (RSI) combines the careful use of pretreatment interventions with the administration of induction and paralytic agents to create the ideal environment for ETT placement and is the preferred method in the emergency department (ED).

A patient who cannot be intubated within 3 attempts is considered a failed airway. This scenario occurs in ~3–5% of all cases. Numerous alternative devices including laryngeal mask airways (LMA), introducer bougies, and fiberoptic instruments have been developed to facilitate airway management in these situations. That said, these methods are not failsafe, and roughly 0.6% of patients will require a surgical airway. Emergent cricothyrotomy is the preferred surgical technique for most ED patients.

History

The need for immediate airway intervention in emergency situations always supersedes the need for a comprehensive history and physical exam. Time permitting, perform a rapid airway assessment to identify any risk factors predictive of a difficult airway, inquire about any current medication use and known drug allergies, and try to ascertain the immediate events leading up to ED presentation.

Risk factors predictive of a difficult airway include those that impair adequate BVM ventilation and those that preclude successful placement of an ETT. Examples of the former include patients with facial trauma and distorted anatomy, obese patients with excessive cervical soft tissue, and asthmatic patents with excessively high airway resistances. Examples of the latter include patients with a history of degenerative changes of the spine that limit cervical mobility (eg, rheumatoid arthritis, ankylosing spondylitis), patients with underlying head and neck cancers that distort the normal cervical anatomy, and those with excessive swelling of the airway and surrounding tissues (eg, angioedema).

Physical Examination

Rapidly examine the airways of all critically ill patients. Always consider the presence of concurrent cervical spine injury in victims of trauma and immobilize as appropriate. Carefully examine the face, noting any signs of significant facial trauma and the presence of a beard, both of which frequently impair adequate BVM ventilation. Inspect the oropharynx, noting the presence of dentures; the size of the teeth and presence of a significant overbite; visibility of the soft palate, uvula, and tonsillar pillars (ie, Mallampati classification); and the presence of significant airway swelling. The pooling of blood or secretions in the oropharynx indicates an inability to properly protect the airway. A good adage to remember when assessing the airway is the 3-3-2 rule. The inability to open the mouth 3 finger breaths, a distance from the tip of the chin to the base of the neck less than 3 finger breaths, or a distance between the mandibular floor and the prominence of the thyroid cartilage of less than 2 finger breaths all predict more difficult ETT placement. Assess the range of motion of the cervical spine, provided there is no concern for occult injury.

Laboratory

Although abnormalities on either blood gas analysis (hypercapnia) or pulse oximetry (hypoxemia) may be indicative of an inadequate airway, normal values on either of these studies should not justify the delay of definitive intervention in the appropriate clinical scenario. Progressive abnormalities on serial testing (increasing PaCO₂, decreasing PaO₂) in patients who are clinically decompensating indicates the need for airway intervention.

Imaging

Imaging studies should not be used to predict the need for airway intervention. Obtain a chest x-ray (CXR) in all patients after intubation to confirm proper ETT placement. The tip of the ETT should be visualized approximately 2 cm above the carina. Deeper insertion results in placement into the right mainstem bronchus.