Protamine

After aortic and atrial purse string sutures were placed, 300 IU/kg heparin (Pfizer, New York, NY, USA) was administered directly into the right atrium to maintain an activated clotting time (ACT) > 400 s. After CPB, 1 mg protamine (Fresenius Kabi, Lake Zurich, IL, USA) for every 100 IU of residual heparin activity was used for heparin reversal to an ACT of < 130 s. A standard non-pulsatile CPB technique with moderate hypothermia (bladder temperature 28–30 °C) or deep hypothermia (bladder temperature 18–20 °C) and hemodilution was used depending on the surgical repair. Cardioprotection was achieved with antegrade cold blood cardioplegia. Weaning-off CPB was performed after rewarming to a bladder temperature of at least 36 °C. The Hepcon® Hemostasis Management System Plus (Medtronic, Inc., Minneapolis, MN, USA) was used to optimize and monitor heparin and protamine dosing.
All patients were < 10 kg in body weight and had the CPB pump primed with one unit of packed red blood cells (PRBC). Target hemoglobin while on CPB was 9 g/dL; the transfusion trigger for additional units of PRBC was 7 g/dL. Patients < 3.5 kg or with an antithrombin III deficiency preoperatively also had one unit of FFP added to the prime. One partial unit of plateletpheresis (200 mL) was administered while rewarming prior to separation from CPB in all patients.