Protamine titration to optimize heparin antagonization after cardiopulmonary bypass

Objectives To optimize protamine titration for heparin antagonization after weaning from cardiopulmonary bypass (CPB). Design A prospective, observational trial. Setting Single-center, non-university teaching hospital. Participants Forty patients presenting for elective on-pump coronary artery bypass grafting with or without single valve surgery. Interventions At the end of CPB, the residual amount of heparin in the patient was estimated using a Bull-curve. The total protamine dose was calculated as 1 unit of protamine for 1 unit of heparin. Protamine was administered as 5 aliquots containing 20% of the total protamine dose each, with 2-min intervals. Measurements and main results Activated Clotting Time (ACT) values were measured 2 min after administration of each aliquot. ROTEM(®)-analysis was performed after the full dose of protamine had been administered. After 60% of the total protamine dose had been administered, ACT values were normalized in 86.5% of patients. After the complete dose of protamine had been administered, 61.1% of patients displayed signs of protamine overdose on ROTEM(®)-analysis. Conclusions In patients who present for on-pump coronary artery bypass grafting with or without single valve surgery, a 0.6-to-1 ratio of protamine-to-heparin to antagonize heparin may be sufficient and beneficial for patients.