Physiological Demands of Canadian Armed Forces Reserve Medics During Simulated Tactical Combat Casualty Care

The objective of this study was to measure the physiological demands of reserve medics performing tactical combat casualty care (TCCC) within evacuation scenarios.

Seven active reservist medics (three female) in the Canadian Armed Forces (CAF) completed three self-paced TCCC scenarios developed by a casualty evacuation subject matter expert, based on one- and multi-person evacuations determined to be the most relevant to current CAF operations. Patrol and stretcher carry, trench evacuation, and vehicle extrication were performed on three consecutive days. The casualty was an 86.1 kg manikin dressed in military attire. Participants performed a 1-kilometer pre-fatigue approach march prior to the "patrol" and "trench evacuation" scenario. Oxygen consumption (VO₂) and heart rate (HR) were measured continuously, and rating of perceived exertion (RPE) were recorded at the end.

Participants' mean age was 26 ± 5 years, mean height 179.7 ± 9.6 cm, and mean unloaded mass 83.4 ± 12.2 kg. They wore minimal tactical equipment weighing 27.0 ± 2.1 kg. The patrol scenario total time was 12 ± 2 min, mean relative VO₂ was 26.4 ± 5.8 mL/kg/min (load adjusted 19.6 ± 4.1 mL/kg/min), which was 54% of estimated VO₂max, and mean HR was 166.0 ± 11.3 bpm (88% of HRmax). Final RPE was 16.0 ± 0.8. The trench scenario total time was 12 ± 2 min, mean relative VO₂ was 30.2 ± 4.0 mL/kg/min (load adjusted 22.8 ± 2.5 mL/kg/min), which was 64% of estimated VO₂max, and mean HR was 159.0 ± 13.7 bpm (84% of HRmax). Final RPE was 16.4 ± 1.1. The vehicle extrication scenario total time was 102 ± 25 s, mean relative VO₂ was 22.2 ± 5.5 mL/kg/min (load adjusted 18.2 ± 4.4 mL/kg/min), which was 46% of estimated VO₂max, and mean HR was 153.0 ± 15.8 bpm (81% of HRmax). Final RPE was 13.4 ± 1.1.

Reserve medic TCCC training scenarios demonstrate high relative physiological demand as determined through directly measured VO₂ and HR. The VO₂ demands of these tasks exceed those required to successfully perform the CAF physical employment standard. Due to these physiological requirements, occupational training courses should prioritize combining fitness training at a relatively high intensity with medical tasks to best simulate the occupational environment.