ABSTRACT
When oxygen delivery is reduced below the level of mandatory oxygen con sumption, there is a forced reduction in oxidative metabolism (1,2). This is known as oxygen debt and is associated with an increase in the metabolic pa rameters of ischemia, which can be most directly related to the induction of anaerobic metabolism. The major metabolic fuel that cannot be effectively me tabolized in the absence of oxygen is glucose. Consequently, there is a rise in the arterial blood lactic acid (lactate), which occurs when muscle beds, liver, and kidney are hypoperfused below a critical level. Enzyme systems that me tabolize substrates other than glucose also are forced into anaerobic metabolism and, as a result, amino acids and other metabolic acids also accumulate into plasma, together with phosphoric acid, due to the breakdown of adenosine tri phosphate (ATP) and its degradation products.
