Hypoxia (10% and 5% oxygen) maintained total left ventricular oxygen consumption via increased coronary flow, while complete anoxia caused negative arteriovenous differences for lactate and pyruvate.
How do different degrees of hypoxia affect myocardial metabolism and coronary blood flow in intact dogs?
In intact dogs, myocardial oxygen consumption is maintained during moderate to severe hypoxia through compensatory increases in coronary flow and oxygen extraction, but complete anoxia leads to myocardial lactate and pyruvate production.
Coronary blood flow and myocardial oxygen and carbohydrate metabolism were studied in normal intact dogs subjected to different Degreess of hypoxia. Total left ventricular oxygen consumption was maintained during administration of 10 per cent and 5 per cent oxygen owing to increase in coronary flow and myocardial oxygen extraction. Ten per cent oxygen administration had little effect on carbohydrate uptake by the heart. Five per cent oxygen resulted in decreased coefficients of extraction for glucose, lactate and pyruvate, but total utilization was maintained. Complete anoxia resulted in negative arteriovenous differences for lactate and markedly decreased or negative values for pyruvate.
Hackel et al. (Mon,) conducted a other in Normal intact dogs. Hypoxia vs. Baseline/normal oxygenation was evaluated on Coronary blood flow and myocardial oxygen and carbohydrate metabolism. Hypoxia (10% and 5% oxygen) maintained total left ventricular oxygen consumption via increased coronary flow, while complete anoxia caused negative arteriovenous differences for lactate and pyruvate.