Influence of propranolol plasma levels on hemodynamics during coronary artery bypass surgery

Hemodynamic effects of propranolol during coronary artery surgery were investigated in 26 patients who chronically took propranolol and who received a standardized morphine/diazepam/pancuronium/halothane anesthetic. Effects were shown by correlating logarithm of the plasma propranolol concentrations versus percentage change in hemodynamics following stressful events (induction, intubation, skin incision, sternotomy, and sternal retraction). Log propranolol and hemodynamics following cardiopulmonary bypass also were correlated. A broad range of propranolol levels were observed. Levels (range and mean +/- SD) were preinduction 0-96 (25.6 +/- 21.6) ng/ml; preincision 0-86 (27.2 +/- 24.4) ng/ml; and sternal retraction 0-92 (28.2 +/- 25.4) ng/ml. The range of hemodynamic responses to stressful events also was broad. Representative changes between preincision control and sternotomy were (range and mean +/- SD): HR-8-30 (7 +/- 10) beats/min; PCWP 1-21 (8.5 +/- 4.6) mmHg; CI -0.2-1.1 (-0.2 +/- 0.7) 1 X min-1 X m-2, and SVR -244-1,288 (310 +/- 388) dyn X s X cm-3. By the time of sternal retraction, CI had declined from preincision values in 14 patients. Linear regression analysis demonstrated an inverse correlation between log propranolol and magnitude of HR, MAP, PCWP, and CI response to stressful stimulation. A direct but statistically weaker correlation with SVR also was seen. Significant correlations between log propranolol versus hemodynamic response to anesthetic induction and versus postcardiopulmonary bypass hemodynamics were not observed.