Hemodynamics during General Anesthesia in Patients Receiving Propranolol

To determine whether orally administered propranolol contributes to untoward hemodynamic function during general anesthesia, the authors divided patients undergoing myocardial revascularization into two groups: One group (n = 9) did not receive propranolol orally in the preoperative period. The other group (n = 10) received oral doses until five to six hours before induction of anesthesia, and the majority had demonstrable serum propranolol levels. Control (preanesthetic) hemodynamic values were determined following morphine—scopolamine premedication and percutaneous vascular cannulation. Post-intubation measurements were done following the sequence of thiopental, 2-3 mg/kg, succinylcholine, 1 mg/kg, and orotracheal intubation. Measurements were repeated at the following intervals after starting halothanenitrous oxide and pancuronium, 0.1 mg/kg: 5, 15, 30, and 60 min. Comparison of hemodynamic values in the propranolol and nonpropranolol groups revealed significantly lower heart rates at all measurement periods in the propranolol group. The groups showed no differences in cardiac output, mean arterial pressure, stroke volume, systemic peripheral vascular resistance, blood-gas, pH, or acid—base values. Patients in both groups responded to the “stress” of endotracheal intubation with increased heart rates and mean arterial pressures. In the absence of overt resting myocardial pain and frank left ventricular power failure, continuing oral administration of propranolol in moderate doses (average 140 mg/ day) until a few hours before general anesthesia with thiopental-succinylcholine-nitrous oxide- halothane and pancuronium does not appear to lead to unusual hemodynamic function in patients who have coronary-artery disease.