Effects of morphine and halothane on canine cardiac function before and after cardiopulmonary bypass.

In an effort to compare the effects of anesthetics on cardiac functions and metabolism, mongrel dogs were anesthetized with morphine (3 mg/kg, N2O 50% in oxygen) or halothane (0.7%, N2O 50% in oxygen). Hb, Ht, pO2, pCO2, pH, O2 content, lactate, and pyruvate in the arterial and coronary sinus blood were measured and ECG, LVP, CVP, AP, and CO were recorded. Aorta was cross-clamped for 30 min under cardiopulmonary bypass (CPB). Hemodynamic and metabolic survey were continued until 120 min of recovery period. Results were as follows: Hemodynamics, such as LVP, AP, and CO, were depressed after CPB, then gradually returned to control level. Subendocardial ischemia observed through ST depression and QRS widening on ECG, as well as DPTI/TTI ratio under 1.0, disappeared in the recovery period. Lactate was produced by the heart after anoxic arrest and was extracted at 120 min after CPB. Halothane and morphine did not show any significant differences of effects on cardiac function and metabolism in this study.