Simulated Cold-Weather Casualty Evacuations: An Initial Comparison Between a Traditional and Novel Casualty...

Military units must prepare for combat and casualties in cold-weather environments that will produce unique medical intervention and evacuation requirements. An early technology demonstration of a cold-weather casualty evacuation (CASEVAC) Ecosystem (version 0.5), composed of a Casualty Protection Unit (CPU) and a tent shelter, has been engineered to provide a "bubble of warmth" that provides for rapid environmental sheltering with active heating of the casualty. The system also serves as an environmental shelter for a casualty care practitioner to perform their duties safely. This contrasts with the non-insulated design of the traditional plastic rescue litter (SKED), which does not provide any additional sheltering from cold weather. The purpose of this study was to compare human physiological responses during CASEVAC transport with the SKED and CPU systems during cold-weather military field training. Specifically, this study compared heart rate, skin temperature, and core temperature of simulated human casualties and medical team members during CASEVAC transport with the SKED and CPU systems.

Twenty-five military personnel (all male; mean ± SD age: 24 ± 3 year; height: 181 ± 7 cm; weight: 84.4 ± 14.6 kg) volunteered for the study. Teams consisting of one medic and 4 litter bearers worked to simulate casualty treatment at a point of injury, package the casualty in the respective CASEVAC transport system, and then haul the casualty 400 m from the point of injury to their respective casualty collection points over snow-covered ground.

Casualty core (SKED: 37.1 ± 0.2 °C, CPU: 36.9 ± 0.4 °C) and skin (SKED: 31.3 ± 0.9 °C, CPU: 30.2 ± 0.7 °C) temperature did not reveal any significant differences between CASEVAC systems, nor were there any differences between packaging (SKED: 7.3 ± 4.4 minute, CPU: 5.0 ± 2.8 minute; P = .46) or transport (SKED: 12.0 ± 2.9 minute, CPU: 9.5 ± 2.1 minute; P = .13) times between systems.

Findings suggest that the CASEVAC Ecosystem was not inferior to the SKED system, given there were no differences in heat loss protection performance, packaging times, and transport efficiency between systems. It is anticipated that further development and testing of the novel CASEVAC Ecosystem system will benefit from this study's outcomes to improve heat loss protection performance for casualties.