AN EVALUATION OF HAND IMMERSION FOR REWARMING INDIVIDUALS COOLED BY IMMERSION IN COLD-WATER

The hypothesis that hypothermic individuals can be actively rewarmed i n the field by immersion of the extremities in hot water was investiga ted. Three techniques for rewarming subjects with lowered deep body te mperatures were compared: a) whole body immersion to the neck in water at 40 degrees C: b) immersion of two hands plus forearms only in wate r at 42 degrees C; and c) passive rewarming. The suggestion that the f all in deep body temperature resulting from immersion to the neck in w ater at 15 degrees C could be: arrested by immersing both arms in wate r at 42 degrees C war also investigated. Results indicated that immers ion to the neck in hot water was clearly the most effective rewarming technique. No significant difference (p > 0.05) was observed in the de ep body temperature response during passive rewarming or during immers ion of both hands and forearms in water at 42 degrees C. In the later condition some increase in peripheral blood flow to the hands may have occurred and resulted in a heat input of approximately 12 W, but any benefit from this war negated by an associated significant decrease (p > 0.05) In intrinsic heat production, immersing the arms in hot water during immersion to the neck in cold water appeared to accelerate rat her than decelerate the rate of fall of deep body temperature. We conc luded that hand rewarming, although theoretically attractive, is ineff ective in practice and could be detrimental in some circumstances, by suppressing intrinsic heat production or precipitating re warming coll apse.