Anti-thrombin III (ATIII) vs Placebo in Children (<6mo) Undergoing Open Congenital Cardiac Surgery

The purpose of this study is to test whether the administration of ATIII during the intra-operative period results in improved anticoagulation for cardiopulmonary bypass (CPB) and an attenuation of the activation of the coagulation cascade, as represented by a decrease in fibrin degradation products. The investigators believe this benefit would extend into the post-operative period resulting in a decreased incidence of thrombosis generation, as represented by a decrease in fibrin degradation products in the ICU period.