Serum epinephrine and norepinephrine during valve replacement and aorta-coronary bypass.

A comparison of the levels of serum epinephrine, norepinephrine and blood pressure was made in 25 patients undergoing aorta-coronary bypass or valve replacement who were anaesthetized with a nitrous oxide-narcotic technique. Serum epinephrine and norepinephrine were measured in arterial samples drawn pre-induction, post-induction, before cardiopulmonary bypass, two and eight minutes after initiation of cardiopulmonary bypass, 20 minutes before termination and after termination of cardiopulmonary bypass. In both patient groups significant increases in epinephrine and norepinephrine occurred befored cardiopulmonary bypass, with accompanying increase of blood pressure in the valve replacement patients. During cardiopulmonary bypass an initial hypotensive response (p less than 0.001) was recorded, followed by a significant increase in blood pressure and epinephrine in both groups. After cardiopulmonary bypass, aorta-coronary bypass patients had epinephrine, norepinephrine and blood pressure equal to levels before cardiopulmonary bypass. In contrast, serum epinephrine continued to rise in the valve replacement patients, with a gradual recovery of blood pressure to pre-bypass levels. These findings demonstrate significant differences in blood pressure and catecholamine response in patients with valvular disease from patients with coronary artery disease.