Postoperative complications after cardiac surgery are mainly caused by the detrimental effects of cardiopulmonary bypass (CPB) on hemodynamics and humoral factors. We studied the effects of prostaglandin E1 (PGE1) infusion on CPB induced organ failure. Twenty-four patients who underwent coronary bypass surgery with normal preoperative cardiac and renal function were divided into two groups. PG group (n = 11) was given PGE1 (0.03-0.05 microgram/kg/min) during CPB while the control group (n = 13) was not. Hemodynamic studies with the Swan-Ganz catheter and renal function tests including serum creatinine (Cr), serum beta 2-microglobulin (s-BMG) and urine beta 2-microglobulin (u-BMG) measurements were performed 24 hours after surgery. After CPB, alpha-adrenergic agent requirement was higher in the PG group than in the control group. In the PG group, the mean cardiac index was slightly higher and the mean left ventricular stroke work index was lower than in the control group. Although the mean systemic vascular resistance index was lower in the PG group, the mean pulmonary vascular resistance index was higher because of the vasoconstrictive action of alpha-adrenergic agents. These differences were seen only immediately after surgery; hemodynamic parameters in both groups were at the same level 3 hour postoperatively. Immediately after surgery, creatinine in the PG group was significantly lower than in the control group. While there was no significant differences in s-BMG between the two groups, u-BMG at 6 and 12 hours postoperatively in the PG group were significantly lower than in the control group.(ABSTRACT TRUNCATED AT 250 WORDS)