Predicting difficult airways using the intubation difficulty scale: a study comparing obese and non-obese patients.

STUDY OBJECTIVE To compare intubation difficulty in obese and non-obese patients by intubation difficulty scale (IDS), intubation duration measurement, and oxygen saturation (SaO(2)) levels. DESIGN Prospective, controlled study. SETTING Operating room of a tertiary-care hospital. PATIENTS 204 ASA physical status I, II, and III adult patients who underwent elective surgery with endotracheal intubation. INTERVENTIONS AND MEASUREMENTS Preoperative airway parameters, intubation duration, IDS scores, and lowest SaO(2) during intubation were recorded. MAIN RESULTS IDS scores were higher in the obese group than the non-obese (2.29 +/- 0.45 and 1.26 +/- 0.2, respectively, P = 0.03). Intubation duration was 45.1 +/- 6 sec for obese versus 36.8 +/- 2.6 sec for the non-obese group (P = 0.20). The lowest SaO(2) recorded was 97%, with no difference noted between groups. Mallampati class >or=3 was found to positively predict intubation difficulty scores greater than 5. CONCLUSIONS Difficult intubation was more prevalent among obese than non-obese patients, but intubation duration and lowest SaO(2) levels during intubation were not. Moreover, the modified Mallampati test was found to be a moderately good (60%) predictor of difficult intubation among obese patients.