The Evaluation of Hemorrhage in Cardiac Patients Who have Undergone Extracorporeal Circulation

Abstract

The present study defines excessive bleeding in patients who undergo cardiopulmonary bypass, and evaluates the use of coagulation testing to predict those patients that bleed excessively. Evaluation of 774 consecutive patients undergoing aortocoronary bypass surgery was carried out. Cardiopulmonary bypass consisted of a bloodless prime and a Harvey bubble oxygenator. In the postoperative period, excessive hemorrhage was defined as that exceeding 600 ml chest tube drainage in the first eight hours. One hundred and sixty-three patients (21%) were noted to be in this category. Excessive bleeding postoperatively was best predicted by a PTT greater than 45 seconds, a PT greater than 19 seconds, a fibrinogen level less than 225 mg/dl and a TFT equal to or less than 1:32. These laboratory findings occur singly or in combination. The assessment of platelet, numbers or function and fibrin(ogen) split products were of no prognostic value. Using these criteria, the re-exploration rate for excessive hemorrhage and/or tamponade was 0.6 per cent (5 out of 774 patients). No preoperative laboratory test of hemostatic function was useful in predicting coagulopathies resulting from cardiopulmonary bypass.

Changes in Blood Coagulation During and Following Cardiopulmonary Bypass:Lack of Correlation With Clinical Bleeding

“…Milam and colleagues 5 and other investigators have reported similarly low platelet levels in patients who did not require red cell transfusion, nor bleed excessively. 3,47 However, Holloway and coworkers 48 found that the combination of decreased platelet number and function and increased fibrinolysis correlated significantly with postoperative blood loss, whereas the individual changes did not. Khuri and coworkers 49 also suggested that increased fibrinolysis may play a role in platelet dysfunction following CPB.…”

Increased fibrinolytic activity in patients undergoing cardiopulmonary bypass operation

“…Occasionally, excessive hemorrhage occurs in patients after cardiopulmonary bypass (CPB) surgery [l-31. Bleeding is usually due to abnormal coagulation function rather than to a surgical cause [3][4][5]. A rational approach to the management of such bleeding requires careful assessment of hemostatic function.…”

Mulher de 69 anos de idade com infarto do miocárdio e choque no período pós-operatório de revascularização do miocárdio

“…O grande problema é identificar se o sangramento é de causa cirúrgica ou de anormalidades da coagulação 10 . A identificação destas últimas na avaliação pré-operatória pode ajudar a predizer coagulopatia após circulação extracorpórea 10 , assim como a utilização de medicamentos como: ácido aminocapróico, ácido tranexâmico, aprotinina e desmopresina reduzem o sangramento no pós-operatório 11,12 .…”