Increased tolerance to cold induced by hyperoxia in hypothermic dogs.
In dogs acutely immersed in cold water (8-13 degrees C) oxygen uptake increased and rapidly reached a maximum value (CV02 Max). A few minutes after the start of immersion colonic temperature began to fall more or less rapidly depending on the dog but always in a linear fashion. Twenty min. after the start of immersion the inspired air was switched from air to a 60% O2/40% N2 gas mixture. The switch to the hyperoxia gas mixture slowed down or even stopped the fall in colonic temperature. Concomitantly a lowering of plasma lactate concentration was observed. It may be concluded that hyperoxia improves the cold tolerance of dogs exposed to a severe cold stress. This improvement may be due to a direct effect of hyperoxia on cellular metabolism. However other effects induced by hyperoxia cannot be ruled out.
D000818:Animals; D001784:Blood Gas Analysis; D001831:Body Temperature / Q000187:drug effects; D001833:Body Temperature Regulation / Q000187:drug effects; D004285:Dogs; D006454:Hemoglobins / Q000378:metabolism; D007036:Hypothermia, Induced; D007101:Immersion; D007700:Kinetics; D010100:Oxygen / Q000097:blood / Q000494:pharmacology*; D010101:Oxygen Consumption; D013997:Time Factors
D006454:Hemoglobins; D010100:Oxygen