Effects of platelet transfusion on post cardiopulmonary bypass bleeding

A common complication of cardiopulmonary bypass (CPB) surgery is post-operative bleeding that may result in re-exploration. Bleeding is often due to the coagulopathy that follows the procedure, rather than the surgical technique. Etiology of this coagulopathy has been attributed to platelet dysfunction. We reviewed the medical records of 592 patients who had undergone CPB surgery between 1992 and 1994. Bleeding times (both pre and post operative) in treated (those who received platelets) and untreated patients were recorded where available. Both groups showed a rise in bleeding time (295 sec versus 192 sec, respectively, p<0.001). However, the treated group had a greater increase in the bleeding time compared to the un-treated (p<0.05). The result was the same when we compared 2 subgroups with similar pre-operative bleeding times. When the treated group was subdivided into those who received >10 units of platelets and those who received <10 units, there was no significant difference in the increase in their bleeding times (p>0.1). Administration of platelets did not improve bleeding time abnormalities induced by CPB. Both treated and untreated groups had a significant rise in their bleeding times, irrespective of the amount of platelets administered. The mean rise in the bleeding time in patients who bled significantly to require surgical re-exploration (but did not receive platelets) was not significantly different from those who received platelets. These observations suggest that the administration of platelets has no clinical benefit in improving bleeding time following CPB.