Use of the activated coagulation time in cardiac surgery. Effects on heparin-protamine dosages and bleeding.

A standard heparin-protamine protocol was used for a series of 44 patients. In a second series of 82 patients. Activated Clotting Time (ACT) by the Hemochron method was used to control heparinization and its reversal with protamine. The two groups was similar in regard to surgical procedures, pump-times and perfusion technique. Patients in group II controlled by Hemochron received in average 13% less heparin and 48% less protamine than patients in group 1 (p less than 0.001 Student's t-test). The intra-operative blood loss was on an average 50% less in group II than in group I (p less than 0.001). There was, however, no significant difference in regard to postoperative bleeding. The introduction of the ACT test thus resulted in reduced dosages of heparin and protamine and in a reduction of intra-operative bleeding, while surgical technique seems to be the main factor in the control of postoperative bleeding.