Practical control of hemostasis
Hemostasis is a tripartite function depending on vascular integrity, platelet function, and coagulation factors. Bleeding represents a defect in hemostasis, and abnormal bleeding represents blood loss in excess of what Could be expected in a given patient at that stage in the procedure. For example, during cardiopulmonary bypass the hemostatic mechanism is essentially totally paralyzed by heparin and that is to be expected. Following bypass termination and heparin reversal, total hemostatic paralysis is not to be expected and would require evaluation and treatment before the chest could safely be closed. Evaluation of abnormal bleeding must include an examination of all three parts of the hemostatic mechanism.
This review is divided into four parts: (1) preoperative evaluation; (2) intraoperative period, pre-bypass and intrabypass; (3) intraoperative period, bypass, and postoperative period; and (4) an approach to the bleeding patient.
The best method for detecting hemorrhagic diathesis is a properly taken history. One of the most important items to be checked in the history is the hemostatic response to a prior surgical experience. With respect to any bleeding episode, the history should establish severity, site, duration, and etiology as well as similar episodes, age at onset of symptoms, family history, and any related information the patient may think relevant. Especially important in the history is a detailed record of drug ingestion. In addition to asking about the use of aspirin, drug history should include details about occupation and exposure to toxic agents or ionizing radiation. The age at onset is an . . .