Use of aprotinin in knee replacement surgery.

We have studied the effect of aprotinin on blood loss and subsequent blood transfusion in 17 patients undergoing knee replacement surgery. Patients receiving aprotinin (total dose 2,000,000 kallikrein inhibiting units) received fewer units of blood than control patients (P < 0.05), although there was no significant difference in blood loss between the two groups. The study was stopped when one patient in the aprotinin group needed an above-knee amputation because of ischaemia secondary to arteriovenous thrombosis after knee replacement surgery. Although the patient had peripheral vascular disease which could have accounted for the thrombosis, the role of aprotinin under tourniquet conditions is unclear.