Effects of halothane anesthesia on myocardial contractility, coronary as well as systemic hemodynamics, and myocardial metabolism in dogs.

Halothane depressed coronary and other systemic circulations as arterial halothane concentration rose in dogs. Myocardial oxygen consumption decreased as the cardiac action, especially "myocardial contractility", was depressed, while the whole-body oxygen usage remained steady. Lactate and pyruvate levels in arterial, mixed venous, and coronary venous blood did not show any signs of tissue hypoxia or development of anaerobic metabolism even in very deep halothane anesthesia. Coronary blood flow seemed well maintained for the demand, and changed almost in parallel with the myocardial oxygen consumption during the observation.