In-Flight Deterioration Occurs Early in Aeromedical Trauma Patients

Reliably defining the risk of adverse in-flight events in aeromedical trauma patients could enable more informed pre-departure treatment and guide central asset allocation to achieve better system-level outcomes. Unfortunately, the current literature base specifically examining the in-flight period is sparse. Flight duration is often considered a proxy for the risk of in-flight deterioration; however, there is limited data to support this commonly held assumption. This paper examines the association between flight duration and the risk of in-flight deterioration in aeromedical trauma patients. A total of 2927 cases of aeromedical transport for acute trauma were retrospectively examined, and the time to first hypotension was recorded. Cases were categorised as either primary or inter-hospital transfer retrievals. Cases were also subclassified as being a primary Traumatic Brain Injury or not based on several criteria, including initial GCS. The median time to hypotension was 11.5 min overall, 10 min in primary retrieval cases, and 15 min in inter-hospital transfer cases (p = 0.049). Notably, after approximately 50 min, a significant plateau in cumulative risk was observed. Isolated TBI cases had a significantly higher overall rate of in-flight hypotension, at 39.5% compared to 9.2%. Overall, this paper supports the physiologically plausible assumption that longer aeromedical transfer times are associated with an increased risk of deterioration during flight. It also demonstrates that deterioration tends to occur early in flight, raising questions as to why this might occur.