Physiologic Changes in Acute Anoxia With Anesthesia and Hypothermia

¹ From the Department of Surgery (Anesthesia) and Medicine (Neurology), University of California Medical Center, Los Angeles, California

The effects of anoxia induced by the inhalation of 100% nitrogen were studied in 47 cats. Measurements were made of the animals' physiologic responses to anoxia, combined with the effects of barbiturate and hypothermia. Results suggest that resuscitation was easier with those cats which had been subjected to severe hypoxia under light or no anesthesia rather than deep anesthesia. The electroencephalogram was found to be the most sensitive index of the physiologic state of the animal. There was a great variability in sensitivity to anoxia in different animals subjected to identical experimental conditions. Hypothermia afforded a significant protection against the effects of anoxia. This protective effect was enhanced if no anesthetic drug had been previously administered.