In-Flight Medical Events on Commercial Airline Flights.

Importance: In-flight medical events are an inevitable challenge in commercial aviation. Managing these events is complicated by constrained medical resources and delayed access to definitive care. Objective: To characterize the epidemiology of in-flight medical events and identify factors associated with aircraft diversion, hospital transport, and in-flight mortality. Design, Setting, and Participants: This cohort study included 77 790 in-flight medical events reported to a global ground-based medical support center from January 1, 2022, through December 31, 2023. All passengers experiencing an in-flight medical event across 84 participating airlines during the study period were included. Data were collected from consultations initiated by flight crew via radio or satellite communication with a dedicated ground-based physician. No demographic or clinical exclusions were applied. Exposures: Medical conditions occurring during commercial flights that prompted contact with the ground-based support center. Data included clinical presentation, in-flight management, passenger demographics, involvement of volunteer medical professionals, and disposition. Main Outcomes and Measures: Primary outcome was aircraft diversion, and secondary outcomes were hospital transport and in-flight mortality. Descriptive statistics, univariate analyses, and multivariable analyses were used to identify clinical and operational variables associated with these outcomes. Results: Among 77 790 in-flight medical events, the overall incidence was 39 events per 1 million enplanements, with 1 event per 212 flights, or 17 events per billion revenue passenger kilometers. The median (IQR) age of affected passengers (42 316 females [54.4%]) was 43 (27-61) years. Aircraft diversion occurred in 1.7% of cases, most frequently due to neurologic (41%) and cardiovascular (27%) conditions. Suspected stroke (adjusted OR [AOR], 20.35; 95% CI, 12.98-31.91) and acute cardiac emergencies (AOR, 8.16; 95% CI, 6.38-10.42) were the factors associated with the highest odds of diversion. The involvement of a physician volunteer was also associated with increased odds of diversion (AOR, 7.86; 95% CI, 4.49-13.78). Conclusions and Relevance: In this cohort study of 77 790 in-flight medical events, these events occur more frequently than previously reported. Serious neurologic conditions, cardiac events, and physician volunteer involvement are each associated with higher odds of diversion. These findings contribute to the understanding of in-flight medical event frequency and outcomes and may inform policy, flight crew training, and diversion protocols.