Casualty Evacuation by Female Litter Teams Under Hot-Dry Conditions
ARMY RESEARCH INST OF ENVIRONMENTAL MEDICINE NATICK MA
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A Defense Womens Health Research Program sponsored protocol was conducted at Yuma Proving Ground YPG, AZ, on 19-27 September 1995. Four female subjects participated in four activities in a hot, dry environment walk-rest exercise in MOPP-0 and MOPP-4 at 3 mph for a maximum of 2 h 40 min and self-paced, two-person litter carriage with a 68 kg 150 lbs casualty in the same uniforms. Metabolic rates for the walking and self-paced litter carriage tasks were also measured. The results are summarized in Table 1. For walking in MOPP-0, mean endurance time ET was 140 plus or minus 40 min and the increase in rectal temperature Tre was 0.93 plus or minus 0.27 C vs. an ET of 29 plus or minus 8 min and a Tre of 1.28 plus or minus 0.40 C in MOPP-4. For the litter carriage the ET values in MOPP-0 and MOPP-4 were 59 plus or minus 35 min vs. 43 plus or minus 19 min and for Tre the values were 0.69 plus or minus 0.51 C vs. 0.76 plus or minus 0.41. For walking, the increased physiological strain related to the chemical protective CP clothing worn in MOPP-4 was the apparent reason for the reduced activity time on the second day. During both days of litter carriage, the most common reason for termination was skeletal-muscular problems rather than heat stress, but the last subject in MOPP-4 stopped with indicators of thermal strain. This suggests that although muscular-skeletal problems were the proximate limiting factor for most subjects, thermal strain would have occurred within a short time. Mean results for Tre were compared with values predicted by two models the Heat Strain Decision Aid HSDA and the SCENARIO model. Comparisons of predictive modeling results to subject responses show reasonable agreement with mean subject responses for both models.
- Stress Physiology