Safe use of cardiopulmonary bypass (CPB) requires massive doses of intravenous unfractionated
heparin. At end-CPB, residual heparin is neutralized with intravenous injection of protamine
sulfate. This prospective, randomized, controlled study will be conducted in 82 voluntary
subjects admitted for elective, first intention, cardiac surgery requiring cardiopulmonary
bypass. Each will be randomly assigned to one of two groups. The control group will be
submitted to a standard protamine infusion of 1.3mg :100U of the total heparin dose given
during bypass. The test group will receive an infusion of protamine (over 15 minutes) until
activated clotting time (ACT) values (determined every 3 minutes) depict a plateau, sign that
the optimal protamine to heparin ratio has been attained. The investigators hypothesize this
new in vivo titration method to be as efficient as the standard protocol (adequacy of heparin
neutralization, % heparin rebound, bleeding, and transfusion), and potentially safer by its
ability to prevent protamine overdose and its deleterious impact on platelet function.15
Principal Objective
Evaluate a new in vivo method of titration of protamine sulfate.
Secondary Objective
Evaluate the impact of this method on the adequacy of heparin neutralization by measuring:
1. platelet count
2. postoperative bleeding
3. transfusion exposure a
4. incidence of heparin rebound