Original Article

Altered Hemodynamic Response To Epinephrine Before and During Cardiopulmonary Bypass in Man

Department of Anesthesiology, American University of Beirut, Beirut, Lebanon

^* Address correspondence to: Anis Baraka, MD, Professor & Chairman, Department of Anesthesiology, American University of Beirut, 850 Third Avenue, 18th Floor, New York, NY 10022.

Abstract

The hemodynamic response to epinephrine was investigated in 10 patients undergoing aorto-coronary bypass surgery. Prior to bypass, the intravenous injections of epinephrine 10 μg increased the mean arterial pressure by 32.6 ± 5.1% associated, with a significant increase of the cardiac output, while the systemic vascular resistance did not show a significant change. In contrast, injection of the same dose of epinephrine during cardiopulmonary bypass and aortic cross-clamp only produced 17.9 ± 8.9% increase of mean arterial pressure associated with a corresponding increase of systemic vascular resistance. The results suggest that the pressor response to epinephrine is significantly lower during bypass as compared to the pre-bypass period.