Mechanisms of bleeding common to virtually all patients after heart surgery are platelet dysfunction, enhanced fibrinolysis, dilution of all components of the coagulation system, and the presence of heparin and protamine. The use of warfarin is increasing in patients with heart disease requiring surgery. The replenishment of vitamin K-dependent factors beyond a normal prothrombin time is not assessable, and the dilution associated with cardiopulmonary bypass can reach coagulopathic levels. Optimal preoperative preparation is required and intraoperative therapy initiated when indicated. Individualized heparin and protamine dosing, antifibrinolytic drug administration, minimization of blood loss and dilution, and minimal time on cardiopulmonary bypass are basic adjuncts to meticulous surgical hemostasis. When bleeding is observed in the postoperative period, a sequential assessment of the probable cause leads to initial therapy while laboratory test results are obtained. Ongoing assessment for hemodynamic instability caused by accumulated mediastinal blood is needed while managing the bleeding patient. A chest radiograph and transesophageal echocardiogram can be useful in diagnosing cardiac tamponade.
Copyright 2000 by W.B. Saunders Company