Hypothermic protection against cerebral edema of ischemia.

Abstract

HYPOXIA and ischemia are well documented as causal agents of cerebral edema and irreversable brain damage. 1-7 Since the permanent deleterious effects of lowered O 2 tension can, to some extent, be protected against by hypothermia, it was of interest to explore the influence of low temperature on the development of cerebral edema during circulatory arrest. In the experiments on rats presented here, deep hypothermia was induced by the closed vessel method of Andjus and resuscitation was accomplished with ultrashortwave diathermy in the early stage of rewarming. 8-11 Significant brain edema was not observed after one hour of circulatory arrest with hypothermia of 3 to 5 C, while moderate hypothermia of 20 C without hypoxia was observed to cause a contraction of the brain. Materials and Methods Forty-six male, Sprague-Dawley rats weighing 150 to 200 gm were used. Twelve of these had hypothermic circulatory arrest while under hypercapnic