Pre-selection of primary intubation technique is associated with a low incidence of difficult intubation in patients with a BMI of 35 kg/m² or higher

Background: The incidence of difficult intubation (DI) in obese patients may reach a two-digit figure. No studies have assessed the effect of primary use of special intubation devices on lowering the incidence of DI. We assessed the effect of primary selection of special intubation techniques on the incidence of DI in patients with a BMI of 35 kg/m² or higher.

Patients and methods: Data from 546 patients with a BMI of 35 kg/m² or higher who underwent bariatric surgery at Wolfson Medical Center from 2010 through 2014 was retrospectively extracted and analyzed for demographics, predictors of DI and intubation techniques employed. Difficult intubation was defined as the presence of at least one of the followings: laryngoscopy grade 3 or 4, need for >1 laryngoscopy or intubation attempt, need for changing the blade size, failed direct laryngoscopy (DL), difficult or failed videolaryngoscopy (VL-Glidescope), difficult or failed awake fiberoptic intubation (AFOI) and using VL or awake AFOI as rescue airway techniques. Primary intubation techniques were direct DL, VL and AFOI. We correlated the predictors of DI with the actual incidence of DI and with the choice of intubation technique employed.

Results: The overall incidence of DI was 1.6% (1.5% with DL vs. 2.2 with VL + AFOI, p = 0.61). With logistic regression analysis, age was the only significant predictor of DI. Predictors of DI that affected the selection of VL or AFOI as primary intubation tools were Mallampati class 3 or 4, limited neck movement, age, male gender, body mass index and obstructive sleep apnea syndrome.

Conclusion: The lower incidence of DI in our study group may stem from the primary use of special intubation devices, based on the presence of predictors of DI.