 Coagulopathy after cardiopulmonary bypass CPB is associated with increased morbidity and mortality. Clot formation and clot stability are important factors in coagulation and hemostasis. As such platelet dysfunction and impaired thrombin generation play a central role in bleeding after cardiac surgery. The primary objective of this study is to evaluate the relationship between point-of-care determined platelet function and thrombin generation and postoperative bleeding in infants and young children undergoing cardiac surgery with cardiopulmonary bypass adjusting for clinically important confounding factors. 