Prostaglandin synthesis inhibitor improves hypotension during normothermic cardiopulmonary bypass.

Hypotension is a major systemic side effect during cardiopulmonary bypass (CPB), especially at normothermia. We previously reported that prostaglandin (PG) might play a substantial role in hypotension. The purpose of this study was to clarify whether a PG synthesis inhibitor (PGSI) could improve hypotension during CPB. Thirty-six patients undergoing cardiac surgery with normothermic CPB (35-37°C) were divided into two groups: a PGSI group (n = 18), whose members were given a PGSI before and during CPB, and a control group (n = 18). In both groups, perfusion flow was sufficient and pressure was maintained at above 45 mm Hg by infusion of metaraminol, a vasoconstrictor. The mean arterial pressure throughout CPB was significantly higher in the PGSI group than in the control group (57 ± 4 vs. 48 ± 3 mm Hg, p < 0.01), whereas the dose of infused metaraminol was significantly lower in the PGSI group (13 ± 7 vs. 21 ± 6 mg, p < 0.01). The blood base excess was not significantly different (1.0 ± 1.6 vs. 1.7 ± 1.9 mmol/L, p = 0.28), and urine output was significantly higher in the PGSI group (503 ± 179 vs. 354 ± 112 ml/hr, p < 0.01). In conclusion, PGSI can improve hypotension during CPB and increase urine output without impairing peripheral circulation.