Evaluation Of Cardiovascular Stress And Mental Workload During Simulated Casualty Evacuation (CASEVAC) Medical Scenarios

Abstract

Service members injured on the battlefield are treated and stabilized by medical providers such as Navy Hospital Corpsmen (HMs) and Search and Rescue Medical Technicians (SMTs). Emerging military strategies have increased reliance on the MV-22 Osprey aircraft to transport injured warfighters from the battlefield to higher levels of care. Unique design and flight dynamics of the MV-22 may introduce substantial environmental and ergonomic barriers to providing high-quality care while en route. This work assesses performance and stress responses of HMs and SMTs during medical scenarios in an MV-22 simulator. PURPOSE Determine performance, cardiovascular stress, and mental workload while providing medical care in an MV-22 fuselage. METHODS Fourteen medical providers (7 HMs, 7 SMTs; mean ± SD age: 27 ± 6 yrs; ht: 177 ± 10 cm; wt: 84.0 ± 14.1 kg) completed two scenarios requiring recognition and management of medical emergencies on a high-fidelity mannequin. Scenarios occurred in a quiet room with ample space, lighting, and comfortable temperature (CON) and in an MV-22 with confined space, noise (105 dB), low light, and temperature variations (21-33°C;OSP). Heart rate (HR) was measured during each scenario while medical experts evaluated participants’ medical performance. Mental workload was assessed using the NASA Task Load Index. Considering training duration between HMs (10 weeks) and SMTs (50 weeks), a mixed-design analysis of variance was used to compare HM and SMT responses between CON and OSP. Significance was set at p < 0.05. RESULTS Medical performance was lower in OSP (mean ± SD: 55 ± 22%) compared with CON (68 ± 15%; p < 0.01). SMT performance was superior to HM in CON (SMT: 77 ± 11, HM: 59 ± 13%; p < 0.01) but not in OSP (p = 0.147). HR was lower in OSP (134 ± 19 bpm) compared with CON (146 ± 21 bpm; p < 0.001). In CON, SMTs had lower HR (135 ± 18 bpm) compared with HMs (157 ± 18 bpm), but similar HR was observed in OSP (p = 0.068). Mental workload was not different between CON and OSP (p = 0.176) or SMTs and HMs (p = 0.151). CONCL Findings suggest that performing simulated medical care in the MV-22 deteriorates performance with no appreciable increases in cardiovascular stress or mental workload between SMTs or HMs. This information is critical to military commands and leadership who oversee medical operations for the Department of Defense.