The effect of body mass index on intubation success rates and complications during emergency airway management

Abstract

We evaluated the effect of body mass index (BMI) on intubation success rates and complications during emergency airway management. We retrospectively analyzed an airway registry at an academic medical center. The primary outcomes were the incidence of difficult intubation and complication rates, stratified by BMI. We captured 1,075 (98 %, 1,075/1,102; 95 % CI 97-99) intubations. Four hundred twenty-six patients (40 %) had a normal BMI, 289 (27 %) were overweight, 261 (25 %) were obese, and 77 (7 %) were morbidly obese. In a multivariate analysis, obesity (OR 1.90; 95 % CI 1.04-3.45; p = 0.04), but not morbid obesity (OR 2.18; 95 % CI 0.95-4.99; p = 0.07), predicted difficult intubation. BMI was not predictive of post-intubation complications. Airway management in the morbidly obese differed when compared with lean patients, with less use of rapid sequence intubation and increased use of fiberoptic bronchoscopy in the former. During emergency airway management, difficult intubation is more common in obese patients, and morbidly obese patients are more commonly treated as potentially difficult airways.

Complications of Airway ManagementDiscussion

“…Colton House et al 20 found that weight does not appear to have a significant correlation with the incidence of laryngeal injury. Likewise, Dargin et al 25 concluded that body mass index was not predictive of postintubation complications. Interestingly, they also found that obesity, but not morbid obesity, predicted difficult intubation.…”

Effect of patient weight on first pass success and neuromuscular blocking agent dosing for rapid sequence intubation in the emergency department

“…In one retrospective study in 1435 patients with trauma in the ED, there was no significant association between BMI and intubation failure, complications or death 15. Another investigation (n=1053) evaluated the effect of obesity and morbid obesity on the presence of a difficult airway, which was defined as the need for three or more intubation attempts 5. Interestingly, obesity predicted a difficult airway, but morbid obesity did not.…”

“…RSI is a technique involving the near simultaneous administration of an anaesthetic agent and a neuromuscular blocking agent (NMBA) to facilitate placement of an endotracheal tube 4. There is the potential that obesity could increase the difficulty of RSI 5. With increased difficulty, patients are more likely to require repeated attempts to place the endotracheal tube, which increases the risk of complications 6 7…”

“…In one study conducted in the ED setting, the body mass index (BMI) of patients with trauma was not a risk factor for failed intubations 15. Another study in the ED showed that obese patients were more likely to have a difficult airway 5. However, weight rather than BMI may be a more practical measure in the ED because BMI is not routinely calculated prior to intubation.…”

The degree of intubation difficulties and the frequency of complications in obese patients at the Hospital Emergency Department and the Intensive Care Unit

“…[10] Some authors postulate that every obese patient can be considered as potentially difficult to intubate, regardless of the indicators. [11] Moreover, the literature reports that not all determinants are always good predictors. [5] There are some findings reporting that for example not only Mallampati classification but also the thyromental distance can produce false-positive results.…”