Thyromental Height Predicts Difficult Direct Laryngoscopy

Thyromental height is the vertical distance between the thyroid cartilage and the anterior border of the mentum in a supine patient. Researchers recorded several anatomic measurements in 314 adult elective surgery patients to determine if thyromental height is a better predictor of difficult direct laryngoscopy than the modified Mallampati test, thyromental distance, or sternomental distance. Difficult direct laryngoscopy was defined as a Cormack-Lehane grade view of III or IV. The laryngoscopist was blinded to anatomic measurements.

At a cutoff value of 5 cm, thyromental height was 83% sensitive and 99% specific for predicting difficult direct laryngoscopy. All other measurements had poor sensitivity (<26%) but good specificity (>80%) for d…