Portable Prehospital Methods to Treat Near-Hypothermic Shivering Cold Casualties

• Published in: Wilderness & environmental medicine Vol. 27; no. 1; pp. 125 - 130
• Main Authors: Oliver, Samuel J., PhD, Brierley, Jennifer L., PhD, Raymond-Barker, Philippa C., MSc, Dolci, Alberto, MSc, Walsh, Neil P., PhD
• Format: Journal Article
• Language: English
• Published: Los Angeles, CA Elsevier Inc 01.03.2016; SAGE Publications
• Subjects: Adolescent; Adult; Body Temperature; Cold Temperature - adverse effects; Cross-Over Studies; Emergency; frostbite; Humans; hypothermia; Hypothermia - therapy; Male; multiple trauma; Random Allocation; rewarming; Rewarming - methods; Shivering; Skin Temperature; thermogenesis; wilderness medicine; Young Adult; frostbite; wilderness medicine; thermogenesis; hypothermia; multiple trauma; rewarming
• ISSN: 1080-6032; 1545-1534
• DOI: 10.1016/j.wem.2015.11.012

Objective To compare the effectiveness of a single-layered polyethylene survival bag (P), a single-layered polyethylene survival bag with a hot drink (P+HD), a multi-layered metalized plastic sheeting survival bag (MPS: Blizzard Survival), and a multi-layered MPS survival bag with 4 large chemical heat pads (MPS+HP: Blizzard Heat) to treat cold casualties. Methods Portable cold casualty treatment methods were compared by examining core and skin temperature, metabolic heat production, and thermal comfort during a 3-hour, 0°C cold air exposure in 7 shivering, near-hypothermic men (35.4°C). The hot drink (70°C, ~400ml, ~28kJ) was consumed at 0, 1, and 2 hours during the cold air exposure. Results During the cold air exposure, core rewarming and thermal comfort were similar on all trials ( P = .45 and P = .36, respectively). However, skin temperature was higher (10%–13%; P < .001; large effect sizes d > 2.7) and metabolic heat production lower (15%–39%; P < .05; large effect sizes d > .9) on MPS and MPS+HP than P and P+HD. The addition of heat pads further lowered metabolic heat production by 15% (MPS+HP vs MPS; P = .05; large effect size d = .9). The addition of the hot drink to polyethylene survival bag did not increase skin temperature or lower metabolic heat production. Conclusions Near-hypothermic cold casualties are rewarmed with less peripheral cold stress and shivering thermogenesis using a multi-layered MPS survival bag compared with a polyethylene survival bag. Prehospital rewarming is further aided by large chemical heat pads but not by hot drinks.