Can the Modified LEMON Score Predict Difficult Intubation?

The LEMON score is a mnemonic for predicting difficult intubation. It stands for Look, Evaluate the 3-3-2 rule, Mallampati score, Obstruction, and Neck mobility (NEJM JW Emerg Med Mar 2005 and Emerg Med J 2005; 22:99). Using a prospective registry of emergency department intubations in Japan, researchers assessed the sensitivity and specificity of the modified LEMON criteria for predicting difficult intubation (defined as requiring >1 attempt). The modified LEMON criteria do not include assessment of the Mallampati score or measurement of thyroid-to-mouth distance (part of the 3-3-2 rule).

Of 4034 intubations, 84% were performed with a direct laryngoscope and, of these, 5.4% were difficult (required more than 1 attempt). Among the direct lar…