Hemorrhage and the use of blood products after adult cardiac operations: myths and realities.

BACKGROUND: Several patient-, procedure-, and prescriber-related factors are thought to influence the decision to administer allogeneic blood products. We reexamine a number of assertions applied commonly to the practice of transfusion in cardiac operations.
METHODS: More than 50 original articles including a total of more than 10,000 patients from 70 centers were reviewed. Data from 5,426 patients operated on between 1990 and 1994 at the Montreal Heart Institute are presented.
RESULTS: From our review of the literature, we conclude that postoperative mediastinal fluid drainage averages 917 mL and that aspirin therapy increases drainage by less than 300 mL in most studies, which should not increase use of blood products, insofar as a strict transfusional protocol is adhered to. Across centers, transfusions can vary eightfold for the same postoperative drainage. Data from our institution show that postoperative mediastinal drainage per se is not influenced by reoperation or by the type of operation. However, total blood losses and transfusion requirements remain increased in reoperative and complex procedures. Excessive mediastinal drainage resulting in increased transfusions occurs in 29% of patients.
CONCLUSIONS: Exposure to allogeneic transfusions remains institution dependent. Constant reevaluation of local practice is essential to implement efficient blood conservation strategies.