A 42-year-old male with a Mallampati class III airway, a thyromental distance of 5 cm, and a mouth opening of 3 cm is scheduled for elective cholecystectomy. Which single airway feature is the MOST reliable predictor of a difficult laryngoscopy in this patient?

• A Thyromental distance less than 6 cm
• B Mallampati class III
• C Combination of multiple predictors rather than any single feature ✓
• D Mouth opening of 3 cm

Explanation

No single bedside predictor reliably identifies a difficult airway in isolation; sensitivity and specificity of individual tests such as Mallampati score and thyromental distance are both limited when used alone. The predictive accuracy improves substantially when multiple tests are combined, which is the basis of multivariate scoring systems like the Wilson score. Thyromental distance < 6 cm and Mallampati III are both concerning but each alone has a high false-positive rate. A mouth opening of 3 cm is at the lower threshold but does not by itself predict laryngoscopic grade.

Reference: Morgan & Mikhail's Clinical Anesthesiology, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.