Influence of Patient Weight on Prehospital Advanced Airway Procedure Success Rates

Previous investigations of the relationship between obesity and difficult airway management have provided mixed results. Almost universally, these studies were conducted in the hospital setting, and the influence of patient body weight on successful prehospital airway management remains unclear. Because patient weight could be one readily identifiable risk factor for problematic airway interventions, we sought to evaluate this relationship.

We conducted a retrospective analysis using the 2020 ESO Data Collaborative dataset. The inclusion criteria consisted of adult patients weighing >30kg with an attempted orotracheal intubation (OTI) and/or blind insertion airway device (BIAD) placement. Separate logistic regression models were developed to determine the influence of weight (dichotomized at 100 kg) on cumulative procedure success for OTI and BIAD, and linear regression models were used to identify trends for each across weight strata.

A total of 45,344 patients met inclusionary criteria, among which 40,668(89.7%) suffered from a medical emergency, followed by 3,130(6.9%) with traumatic injuries, and 1,546(3.4%) attributable to a combined medical-trauma etiology. Cardiac arrest occurred either prior to EMS arrival or at some point during EMS care in 38,210(84.3%) patients. OTI was attempted in 18,153(40.0%) patients, while 21,597(47.6%) had a BIAD attempt and 5,594(12.3%) had both airway types attempted. The overall cumulative insertion success rates for OTI and BIAD were 79.5% and 92.7%, respectively. Altogether, 2,711(6.0%) had no advanced airway of any type successfully placed, which represents the overall failed advanced airway rate. After controlling for patient age, sex, minority status, and call type (medical vs. trauma), weight >100kg was associated with decreased likelihood of cumulative OTI success (OR = 0.64, p < 0.001), but higher likelihood of cumulative BIAD success (OR = 1.31, p < 0.001). Cumulative OTI success was associated with a negative 0.6% linear trend per 5 kg of body weight (p < 0.001) while cumulative BIAD success had a 0.2% positive trend (p < 0.001).

This retrospective analysis of a national EMS database revealed that increasing patient weight was negatively associated with intubation success. A positive, but smaller, linear trend was observed for BIAD placement. Patient weight may be an easily identifiable predictor of difficult oral intubation and may be a consideration when selecting an airway management strategy.