Effect of high oxygen pressure on ground squirrels in hypothermia and hibernation

Abstract

The protective role of hypothermia has been demonstrated in barometric depression or hypoxia, in X irradiation, after intoxication with carbon monoxide or after intoxication with other substances, after severe hemorrhage, hyperuremia, or insulin shock. In the present work ground squirrels (hibernators) in three different metabolic states (euthermia, hypothermia, and hibernation) were exposed to 6 atm of pure oxygen and their survival was measured. The hibernating ground squirrels exposed to 6 atm of pure oxygen lived for over 18 hr, the hypothermic ground squirrels for over 6 hr, and the euthermic ground squirrels for a half-hour only. The oxygen consumptions of ground squirrels in three different physiological states—in hibernation, in hypothermia, and in euthermia—were in the proportion of 1:12:40, while the survival times of these animals show an inverse correlation of 33:13:1. Thus it appears that the lowering of body temperature has a protective role against high oxygen pressure mainly because of a decreased metabolism.