Metabolic Alterations in Brain During Anoxic-Anoxia and Subsequent Recovery

Until a few years ago, it was generally thought that irreversible brain damage would result from any condition that produced a profound cerebral anoxia of greater than eight to ten minutes' duration. This conclusion was based on observations made by physicians during clinical emergencies and by investigators using experimental models in which the onset, degree, and duration of anoxia could be controlled.1-6Most techniques for producing anoxia in the intact animal also produce ischemia and there is some evidence to suggest that cerebral anoxia is exacerbated by ischemia.7However, the results of recent studies with totally ischemic brain tissue suggest that many of the variables measured approach normal after reoxygenation. This has led some workers to question whether cerebral anoxia actually causes irreversible brain damage within so short a period as ten minutes.8-11 If proper protocols are to be established for the treatment of cardiac arrests and