ECMO (extracorporeal membrane oxygenation) functions to support pulmonary and cardiac systems to allow them to recover from illness or until surgical correction can be made. It continuously pumps blood through an oxygenator that imitates gas exchange in the lungs. ECMO is most commonly used for pediatric patients. Cardiopulmonary (CPB) functions as circulatory and pulmonary support to oxygenate and circulate the blood. It allows for the ability to warm and cool the patient as well as perfuse vital organs while the central circulation is being surgically corrected/changed. Both of these intensive life-supporting treatments can cause clotting and bleeding because of exposure of the blood to synthetic surfaces and the process of cannulation, among others. Transfusion support of patients undergoing CPB and ECMO are complex and require knowledge of coagulation and blood product management.