Anaes · Airway management

Airway assessment: the LEMON tool, Mallampati classification & prediction of difficult direct laryngoscopy

Also known as LEMON assessment · Mallampati classification · Mallampati score · Cormack-Lehane grade · Difficult airway prediction · 3-3-2 rule · Wilson score · El-Ganzouri index

Pre-operative airway assessment is the single bedside exercise most consistently examined in the airway viva and short-answer question, because it is the one step that converts an unanticipated crisis into a planned event. The framework rests on four ideas: a small set of anatomical axes — mouth opening, mandibular space, laryngeal position, neck mobility — determines whether a direct line of sight from the incisors to the glottis can be made; the LEMON tool (Look externally, Evaluate the 3-3-2, Mallampati, Obstruction, Neck mobility) packages those axes into a reproducible screen; the Mallampati classification grades the oropharyngeal view and correlates, imperfectly, with the Cormack-Lehane laryngoscopic grade that defines a difficult intubation; and the honest limitation — individual bedside tests have poor positive predictive value, so combined multi-factor scores are used and the assessment exists to inform preparation, not to guarantee prediction. Anchored to contemporary evidence spanning syndromic and physiological difficult airways, the optimisation of video-laryngoscopic intubating conditions, the bronchoscopic management of dynamic airway obstruction, and the airway compromise of anaphylaxis. Built on the Mallampati original prospective study (n=210), the Cormack-Lehane obstetric grading paper, the Shiga bedside-test meta-analysis (35 studies, 50,760 patients), the MACOCHA ICU score derivation and validation (1,000 plus 400 intubations), the modified-LEMON trauma correlation study (n=114), and the El-Ganzouri multivariate risk index (n=10,507).