Abstract 2598: Individualized Heparin and Protamine Management Protocol in Infants Undergoing Cardiopulmonary Bypass for Cardiac Surgery Improves Immediate Post-operative Clinical Outcomes

Use of individualized heparin and protamine management in older children and adults undergoing cardiopulmonary bypass (CPB) has been associated with improved clinical outcomes. We sought to determine if using this method in infants was associated with similar enhancements. Infants 1 month to 1 year of age undergoing CPB were randomized in a controlled clinical trial to either weight based heparin and protamine management using the activated clotting time (ACT) to monitor anticoagulation, or the use of individualized heparin blood concentration calculated by the Hepcon Hemostasis Management System HMS (Medtronic, MN) using a modified protocol. Primary outcome measure was chest tube volume loss at 4 and 24 hours following cardiac critical care unit (CCCU) admission. Secondary outcomes included blood transfusion, duration of ventilation and hospital length of stay. A total of 34 patients (17 in each group), aged 1 month to 1 year, were enrolled in the study. Demographics and pre-operative variables were similar between groups. Patients in the HMS group received significantly more heparin (796 vs. 643U/kg, p<0.01) and protamine (6.1 vs. 3.9 mg/kg, p<0.01) than those in the ACT group. After accounting for age at surgery, bypass time and surgeon in multivariable regression models, patients in the HMS group experienced significantly less blood loss at 4 hours after CCCU arrival (7.6 vs. 9.2ml/kg, p=0.01). Difference in blood loss between 4 and 24 hours after CCCU admission (17.0 vs. 14.6ml/kg, p=0.88) was not significant. HMS group patients had significantly decreased blood transfusions in the CCCU (11 vs. 21ml/kg, p=<0.01), significantly shorter ventilation times (18 vs. 24hrs, p=0.01) and significantly shorter hospital length of stay (168 vs. 193hrs, p=0.01). Thrombosis was observed in 3 of the 17 patients in the ACT group, while none were noted in the HMS group. Higher heparin and protamine dosing, as managed by the HMS device, resulted in more stable levels of anti-Xa during CPB with improved immediate post-operative outcomes including reduced blood loss, transfusions, ventilation time and hospital length of stay. This study may support the use of the HMS device with a modified protocol for infants <1 year of age for heparin and protamine monitoring during CPB.