Predictors of a difficult intubation in the bariatric patient: does preoperative body mass index matter?

The incidence of difficult intubations in morbidly obese patients has been reported to be 12-20%; however, no well-established predictors of a difficult intubation exist for this patient population. Our objective was to evaluate the factors associated with a difficult intubation in morbidly obese patients undergoing laparoscopic Roux-en-Y gastric bypass at an integrated multispecialty health system with a 325-bed community teaching hospital serving 19 counties.

The anesthetic records of patients undergoing LRYGB from 2001 to 2010 were reviewed. Difficult intubations were defined as direct laryngoscopy graded ≥1 on a 0-2 difficulty scale and unplanned fiberoptic intubations. Statistical analysis included chi-square, univariate, and multivariate logistic regression.

A total of 915 consecutive patients underwent LRYGB during the study period. Of these, 3 patients were excluded because of incomplete data. Of the 912 included patients, 25 (2.7%) underwent planned fiberoptic intubation, 830 (91%) had an uneventful intubation, and 57 (6.3%) had a difficult intubation. Difficult intubations were more common in men than in women (11% versus 6%, P = .027). Difficult intubations were not associated with an increasing preoperative body mass index (P = .073), the presence of obstructive sleep apnea (P = .784), or the presence of gastroesophageal reflux disease (P = .335). Multivariate predictors of a difficult intubation were Mallampati class 4 (odds ratio [OR] 2.76, P = .035), abnormal thyromental distance (OR 4.39, P = .001), restricted jaw mobility (OR 3.26, P = .018), and a history of a difficult intubation (OR 4.17, P = .002).

An increased Mallampati class, abnormal thyromental distance, restricted jaw mobility, and a history of difficult intubations were independent predictors of a difficult intubation. An increasing body mass index did not predict for a difficult intubation.