Characterization of Long-range Aeromedical Transport and Its Relationship to the Development of Traumatic Extremity Compartment Syndrome: A 7-year, Retrospective Study

Background: Military aeromedical transport evacuates critically injured patients are for definitive care, including patients with or at risk for developing traumatic compartment syndrome of the extremities (tCSoE). Compartment pressure changes of the extremities have not been determined to be associated with factors inherent to aeromedical transport in animal models, but the influence of aeromedical evacuation (AE) transport on the timing of tCSoE development has not been studied in humans. Using a registry-based methodology, this study sought to characterize the temporal features of lower extremity compartment syndrome relative to the timing of transcontinental AE. With this approach, this study aims to inform practice in guidelines relating to the timing and possible effects of long-distance AE and the development of lower extremity compartment syndrome. Using patient care records, we sought to characterize the temporal features of tCSoE diagnosis relative to long-range aeromedical transport. In doing so, we aim to inform practice in guidelines relating to the timing and risks of long-range AE and postulate whether there is an ideal time to transport patients who are at risk for or with tCSoE. Methods: We performed a retrospective record review of patients with a diagnosis of tCSoE who were evacuated out of theater from January 2007 to May 2014 via aeromedical transport. Data abstractors collected flight information, laboratory values, vital signs, procedures, in-flight assessments, and outcomes. We used the duration of time from injury to arrival at Landstuhl Regional Medical Center (LRMC) to represent time to transport. We compared groups based on time of tCSoE (inclusive of upper and lower extremity) diagnosis relative to injury day and time of transport (preflight versus postflight). We used descriptive statistics and multivariable regression models to determine the associations between time to transport, time to tCSoE diagnosis, and outcomes. Results: Within our study window, 238 patients had documentation of tCSoE. We found that 47% of patients with tCSoE were diagnosed preflight and 53% were diagnosed postflight. Over 90% in both groups developed tCSoE within 48 hours of injury; the time to diagnosis was similar for casualties diagnosed pre- and postflight (P =. 65). There was no association between time to arrival at LRMC and day of tCSoE diagnosis (risk ratio, 1.06; 95% CI, 0.96-1.16). Conclusion: The timing of tCSoE diagnosis is not associated with the timing of transport; therefore, AE likely does not influence the development of tCSoE.