Evaluation and management of bleeding during cardiac surgery.

Patients undergoing cardiac surgery with and potentially without cardiopulmonary bypass (CPB) are at risk for excessive microvascular bleeding. This bleeding often leads to transfusion of allogeneic blood and blood components as well as reexploration. Excessive bleeding after cardiac surgery occurs because of alterations in the hemostatic system pertaining to dilutional thrombocytopenia, excessive hemostatic activation, and exposure to long-acting antiplatelet or antithrombotic agents. Pharmacologic interventions have been extensively reported as means to attenuate the alterations in the hemostatic system during CPB in an attempt to reduce excessive bleeding, transfusion, and reexploration. Prophylactic administration of agents with antifibrinolytic and antiinflammatory properties can decrease blood loss and transfusion. Aprotinin is the most extensively studied and effective blood conservation agent and has the most potent antifibrinolytic and antiinflammatory effects. Other agents, including the lysine analogues with isolated antifibrinolytic properties, may be effective in low-risk patients. The ability to reduce blood product transfusions and to decrease operative times and reexploration rates favorably affects patient outcomes, availability of blood products, and overall health care costs.