Interhospital patient transport by rotary wing aircraft in a combat environment: risks, adverse events, and process...

Helicopter transport of injured or ill patients in Operation Iraqi Freedom is a necessary but often high-risk endeavor. Our facility initiated a thorough process improvement and standardization initiative after several adverse outcomes. This report describes the results after this initiative, and evaluates the applicability of a civilian transport risk assessment tool to the combat environment.

Review of all preflight, in-flight, and postflight records for helicopter medevac missions over a 7-month period. Adverse events included major equipment failures, clinical deterioration, or the need for urgent interventions on arrival. Transport risk scores (TRS) were calculated and assessed for correlation with adverse events.

There were 149 patient transports identified, 95 (64%) for trauma (mean Injury Severity Score, 21) and 54 (36%) for medical illness. Major surgical intervention before the flight was required in 66 (44%), massive transfusion in 29 (20%), and the majority were transported within 8 hours of surgery. In-flight mechanical ventilation was required in 53%, and 20% required vasopressors or cardioactive medications. Adverse events included equipment failures in 17% of flights, in-flight clinical deterioration in 30%, and 9% required an urgent intervention on arrival. However, there were no deaths or significant flight-related morbidities identified. The mean TRS was significantly higher in patients with adverse events (9.1) versus those without (7.4, p < 0.05), but it showed only moderate discriminative ability (area under curve = 0.65, p < 0.01).

Helicopter transport in a combat environment carries significant risk of adverse events because of the patient characteristics and inherent limitations of the transport platform. Strict attention to standardization, training, and process improvement is necessary to achieve optimal outcomes. The civilian TRS had lower discriminative ability in this military setting.