title: Portable Prehospital Methods to Treat Near-Hypothermic Shivering Cold Casualties.
abstract: 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, ~400 ml, ~28 kJ) 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.
authors.affiliation: Extremes Research Group, School of Sport, Health and Exercise Sciences, Bangor University, Bangor, United Kingdom. Electronic address: s.j.oliver@bangor.ac.uk.
authors.forename: Samuel J
authors.initials: SJ
authors.lastname: Oliver
authors.affiliation: Extremes Research Group, School of Sport, Health and Exercise Sciences, Bangor University, Bangor, United Kingdom.
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Brierley
authors.affiliation: Extremes Research Group, School of Sport, Health and Exercise Sciences, Bangor University, Bangor, United Kingdom.
authors.forename: Philippa C
authors.initials: PC
authors.lastname: Raymond-Barker
authors.affiliation: Extremes Research Group, School of Sport, Health and Exercise Sciences, Bangor University, Bangor, United Kingdom.
authors.forename: Alberto
authors.initials: A
authors.lastname: Dolci
authors.affiliation: Extremes Research Group, School of Sport, Health and Exercise Sciences, Bangor University, Bangor, United Kingdom.
authors.forename: Neil P
authors.initials: NP
authors.lastname: Walsh
mesh_terms: D000293:Adolescent; D000328:Adult; D001831:Body Temperature; D003080:Cold Temperature / Q000009:adverse effects*; D018592:Cross-Over Studies; D006801:Humans; D007035:Hypothermia / Q000628:therapy*; D008297:Male; D011897:Random Allocation; D017694:Rewarming / Q000379:methods*; D012768:Shivering; D012881:Skin Temperature; D055815:Young Adult
keywords: frostbite; hypothermia; multiple trauma; rewarming; thermogenesis; wilderness medicine