Henriksson O, Lundgren PJ, Kuklane K, Holmer I, Giesbrecht GG, Naredi P, Bjornstig U. Wilderness Environ. Med. 2015; 26(1): 11-20.
Affiliation
Division of Surgery, Department of Surgical and Perioperative Sciences, Umeå University, Umeå, Sweden (Drs Henriksson, Lundgren, Naredi, and Bjornstig).
OBJECTIVE: The purpose of this study was to evaluate the effect of wet clothing removal or the addition of a vapor barrier in shivering subjects exposed to a cold environment with only limited insulation available.
METHODS: Volunteer subjects (n = 8) wearing wet clothing were positioned on a spineboard in a climatic chamber (-18.5°C) and subjected to an initial 20 minutes of cooling followed by 30 minutes of 4 different insulation interventions in a crossover design: 1) 1 woolen blanket; 2) vapor barrier plus 1 woolen blanket; 3) wet clothing removal plus 1 woolen blanket; or 4) 2 woolen blankets. Metabolic rate, core body temperature, skin temperature, and heart rate were continuously monitored, and cold discomfort was evaluated at 5-minute intervals.
RESULTS: Wet clothing removal or the addition of a vapor barrier significantly reduced metabolic rate (mean difference ± SE; 14 ± 4.7 W/m(2)) and increased skin temperature rewarming (1.0° ± 0.2°C). Increasing the insulation rendered a similar effect. There were, however, no significant differences in core body temperature or heart rate among any of the conditions. Cold discomfort (median; interquartile range) was significantly lower with the addition of a vapor barrier (4; 2-4.75) and with 2 woolen blankets (3.5; 1.5-4) compared with 1 woolen blanket alone (5; 3.25-6).
CONCLUSIONS: In protracted rescue scenarios in cold environments with only limited insulation available, wet clothing removal or the use of a vapor barrier is advocated to limit the need for shivering thermogenesis and improve the patient's condition on admission to the emergency department.