Effects of hemofiltration on serum aprotinin levels in patients undergoing cardiopulmonary bypass

Objective: To determine the effects of hemofiltration on serum aprotinin levels during cardiopulmonary bypass (CPB) surgery. Design: Prospective, randomized study. Setting: University of Washington Medical Center, single institution. Participants: Patients undergoing cardiac surgery without contraindications to aprotinin administration. Interventions: Patients were randomized to full-Hammersmith and half-Hammersmith dosing regimens of aprotinin and were further randomized to hemofiltration or no hemofiltration. Measurements and Main Results: Serum aprotinin levels were studied before CPB, 60 and 120 minutes into CPB, and at the end of CPB before protamine administration. Each group experienced a decrease in serum aprotinin levels with the institution of CPB, attributable to hemodilution and redistribution of aprotinin outside of the vascular compartment. During CPB, aprotinin levels declined further, but no significant difference was observed between patients who received hemofiltration and those who did not. Hematocrit values were significantly higher at the end of CPB in the hemofiltration groups. Patients receiving half-Hammersmith dosing regimens maintained aprotinin levels throughout CPB, which have been shown to inhibit plasmin but were lower than levels previously shown to inhibit kallikrein. Conclusions: Hemofiltration during CPB did not significantly alter serum aprotinin levels in patients receiving half-Hammersmith and full-Hammersmith dosing regimens of aprotinin. Copyright (C) 2000 W.B. Saunders Company.