[Accidental hypothermia in Switzerland (1980-1987)--case reports and prognostic factors]

This retrospective study comprises 234 cases of accidental hypothermia (core temperature less than 35 degrees C) hospitalized in 95 Swiss clinics between 1980 and 1987. The most frequent accidents were alpine (n = 78) in origin, followed by cold exposure after injuries (n = 63) and suicide attempts (n = 43). Hypothermia was induced by cold air in 129 cases and by water in 47 cases. Patients were divided evenly between the degree of hypothermia: 75 mild (32-35 degrees C), 79 moderate (28-32 degrees C) and 66 severe (less than 28 degrees C). Among the survivors the coldest patient had a core temperature of 17.5 degrees C and the longest cardiac arrest with a favourable outcome lasted 4.75 hours. Out of the 234 patients 68 died (29%). We assessed all variables relative to outcome, in particular the mechanism of the accident, the mode of cooling, temperature, circulation, age and sex, underlying diseases, rewarming methods, medication and complications during the hospital course. All variables were tested in two multiple regression analysis models (retrospective model n = 181: prospective model n = 128) with regard to significance (p less than 0.05) and survival. Results are expressed with ODD's ratios (OR). The negative survival factors are asphyxia (OR 30), invasive rewarming methods (OR 20), slow rate of cooling (OR 10), asystole on arrival (OR 9), pulmonary edema or ARDS during hospitalization (OR 8), elevated serum potassium (OR 2/mmol/l) and age (OR 1.03/year). The positive survival factors are rapid cooling rate (OR 10), presence of ventricular fibrillation in cardiac arrest patients (OR 9) and presence of narcotics and/or alcohol during hypothermia (OR 5).(ABSTRACT TRUNCATED AT 250 WORDS)