Efficacy of aprotinin in different doses and autologous blood transfusions in cardiac surgery.

A study was undertaken to compare the two doses of aprotinin and the amount of autologous blood transfused in order to determine the optimal dose of this inhibitor for use in cardiac surgery. A total of 120 patients undergoing elective cardiac surgery from November 1990 to April 1992 took part in this randomized double-blind study. Two groups of 60 patients were treated. Patients in the high-dose group were given the dose of aprotinin recommended by the Hammersmith group (6 million kallikrein inactivator units), the other 60 (the low-dose group) received half the dose. Blood loss from thoracic drains in the postoperative period showed a statistically significant difference between the two groups between 6 and 12 h (a mean loss of 69 ml in the high-dose group versus 109.5 ml in the low dose, P = 0.003). The overall postoperative drainage losses were very similar (537.2 ml in the high-dose group versus 610.9 ml in the low dose). The blood and clotting markers did not differentiate between the high- and low-dose patients. In combination with autologous blood transfusions, a low dose of aprotinin appears as efficient in reducing postoperative blood loss as the high-dose regimen.