Development of a primate model of exposure hypothermia.

A nonhuman primate model of exposure-induced hypothermia was developed and the hemodynamic effects of hypothermia were evaluated in five animals. With decreasing core temperature from 37 degrees C to 33 degrees C there was a 47% increase in heart rate, a 23% increase in mean arterial pressure, a 48% increase in cardiac output, a 260% increase in oxygen consumption, and a 237% increase in minute ventilation. As the core temperature decreased from 33 degrees C to 29 degrees C there were decreases in the heart rate, blood pressure, and cardiac output such that at 29 degrees C these values were not significantly different from the values obtained at 37 degrees C. However, the oxygen consumption was still 180% increased and the minute ventilation 40% higher at 29 degrees C than at 37 degrees C. This model will allow the evaluation of the physiology of hypothermia and the effectiveness of different rewarming techniques.