Airway loss under general anesthesia with an ETT is rare outside of the induction and extubation period. A sudden loss of ETCO₂ tracing in an intubated patient during the maintenance phase of the anesthetic is more likely due to a capnograph disconnect or a mucus plug at the sampling port. It can also relate to a CO₂ production defect, such as embolism or cardiac arrest.

ETT dislodgment can occur, however. Occasionally, a tube may have been “perched” above the cords initially, acting more like a supraglottic airway. This results from intubating without sufficiently advancing the ETT through the cords. In such cases, it can slip out during the case and require immediate replacement.

An LMA is by definition not a secure airway. Loss of ETCO₂ tracing should prompt the following:

• Call for assistance.
  
• Switch to manual ventilation.
  
• Attempt to reposition the LMA either by placing it deeper or retracting it slightly.
  
• If ineffective, don’t waste time with repositioning. If the patient is desaturating, remove the LMA and mask-ventilate the patient.
  
• Consider laryngospasm or bronchospasm and treat accordingly.

Mask ventilation allows for adequate oxygenation and buys time to reassess the situation while maintaining surgical conditions. In general, light planes of anesthesia are a poor strategy with an LMA in place. Movement, swallowing, or coughing is much more likely to dislodge the LMA.

Sedation cases present a unique set of challenges, as you are continuously walking a fine line: sedation and analgesia on one end, and spontaneous ventilation on the other. Airway obstruction is common, but fortunately, often easy to fix:

Start with:

• jaw thrust;
  
• chin lift; and
  
• oral or nasal airway placement (with caution to the nose in patients with bleeding disorders, pregnant patients, or patients with recent nasal surgery).

If these fail to restore ventilation immediately:

• call for help;
  
• stop the anesthetic; and
  
• wake the patient up.

There are varying strategies on airway management during MAC cases, depending on the type of sedation (benzodiazepine/opiate, or propofol-based), the procedure, the patient, and the provider. Some providers opt to deepen the anesthetic and take control of the airway with an oral airway, CPAP, or other airway adjuncts. This is essentially a general anesthetic with a natural airway. This is an acceptable practice, but risky if applied too broadly. As a trainee, this is not the time to improvise alone. Err on the side of a more awake patient who is breathing than a patient who is deeply sedated with periods of apnea.