Casualty Evacuation by Female Litter Teams Under Hot-Dry Conditions

Abstract

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" m 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+40 min and the mcrease in rectal temperature (Tre) was 0.93+0.27 C vs. an ET of 29+8 min and a Tre of 1.28+0 40 C in MOPP-4 For the litter carriage the ET values in MOPP-0 and MOPP-4 were 59±35 min vs. 43 + 19 min and for Tre the values were 0.69+0.51 C vs. 0.76+0.41. For walking, the increased physiological strain related to the chemical protective (CP) clothing worn m 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 m 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. v 14. SUBJECT TERMS Chemical Protection; hot dry climate; heat or thermal stress; litter carriage 17. SECURITY CLASSIFICATION OF REPORT Unclassified