Successful use of a reduced dose of protamine after cardiopulmonary bypass.

The dose of protamine necessary to reverse heparin was examined in 60 patients. Half the patients (controls) received a reversal dose of protamine equal to the entire amount of heparin given them, while half received a reversal dose based on a heparin half-life of 2 hours. Postoperative chest drainage for the first 12 hours and for 48 hours was markedly reduced in patients given the reduced dose of protamine. Platelet counts were higher and postoperative clotting studies varied less from control in patients receiving the smaller dose of protamine. The authors suggest reevaluation of the dose of protamine necessary to reverse the anticoagulant effects of heparin in patients for cardiopulmonary bypass, since larger doses protamine may contribute to the conditions which increase postoperative bleeding.