Airway Management: Prediction, Device Choice, and Confirmed Placement
This domain tests whether you can predict a difficult airway before sedation starts, choose a device matched to the intended depth of anesthesia, and confirm placement with objective data rather than impression. Items typically give a vignette and ask for the next best step among mask ventilation, a supraglottic airway, video laryngoscopy, or front-of-neck access.
Pre-procedure assessment
- Mallampati is graded with the patient seated, head neutral, mouth wide, tongue maximally protruded and no phonation: class I-II lower risk, III-IV higher risk.
- Thyromental distance under 6 cm, sternomental distance under 12.5 cm, interincisor opening under 3 cm, and limited cervical extension all raise risk.
- Also note dentition, beard, obesity, radiation or surgical changes, and prior difficulty. A documented previous difficult intubation is the strongest single predictor available.
- No single test excludes difficulty. Combine tests and prepare for the airway you cannot secure.
Optimizing first attempt
Preoxygenate to end-tidal oxygen above 90 percent where feasible, use ramped or head-elevated positioning in obesity, provide apneic oxygenation by nasal cannula during laryngoscopy, and limit attempts. Each repeated laryngoscopy increases edema and bleeding and lowers success.
Confirmation
Continuous waveform capnography is the standard for confirming tracheal placement and is required whenever an advanced airway is placed; colorimetric devices are adjuncts only. Pulse oximetry lags desaturation by seconds to minutes and cannot confirm tube position.
Worked example
A 58-year-old with BMI 41, Mallampati III, thyromental distance 5.5 cm and limited neck extension requires deep sedation for a procedure. Reasoning: several independent predictors plus obesity mean a plan for difficulty, not a routine plan. Prepare video laryngoscopy, a second-generation supraglottic airway, suction and a functioning oxygen source at the head of the bed; preoxygenate; position ramped; identify who will perform surgical airway access; and do not induce apnea in a patient you cannot mask-ventilate without a rescue pathway.
Traps that cost marks
- Grading Mallampati with the tongue not protruded or the patient supine.
- Treating one reassuring measurement as clearance for any depth of sedation.
- Accepting a good capnogram without watching the waveform over time.
- Confusing Cormack-Lehane laryngoscopic grades with Mallampati oropharyngeal classes.
- Omitting suction and a backup oxygen source from the setup.