Dose for Reversal of Heparin After Cardiopulmonary Bypass

Protamine sulfate is routinely used to reverse heparin anticoagulation after cardiopulmonary bypass (CPB). The conventional dosing strategy of 1 mg protamine per 100 IU of heparin may result in excess protamine exposure, which has been associated with anticoagulant effects, platelet dysfunction, and hemodynamic instability. Recent evidence suggests that lower protamine doses may provide adequate heparin reversal while reducing potential adverse effects.  This multicenter, prospective, randomized, double-blind, controlled trial aims to compare three protamine-to-heparin dosing ratios (1:1, 0.8:1, and 0.75:1) in adult patients undergoing elective cardiac surgery requiring cardiopulmonary bypass. The primary outcome is activated clotting time (ACT) measured 5 minutes after protamine administration. Secondary outcomes include the need for additional protamine administration, protamine-related adverse events, postoperative bleeding, blood product transfusion requirements, and length of intensive care unit stay.  The results of this study may help determine whether reduced protamine dosing can safely achieve effective heparin reversal while minimizing drug exposure and potential complications after cardiopulmonary bypass.