Cold injury complicating trauma in subzero environments

Trauma sustained in freezing and subzero conditions may be complicated by secondary cold injury, either locally to non‐perfused tissue or generally throughout the body, causing hypothermia. A series of experiments, in which the cooling pattern of exposed tissue from which the epidermis was removed was studied, in simulated tissue injury in a subfreezing environment, is reported. Cooling curves for mammalian tissues (simulated exposed wounds) have been constructed for varying conditions of dry bulk temperature and wind speed. For low wind speeds, the time for tissue freezing was reduced by two minutes for every degree Celsius fall in the environmental temperature. The use of a simple polythene “survival bag” halved the rate of cooling to the freezing point of mammalian tissue. Practical implications for first aid and wound management in the subzero environment are discussed.