Platelet function, coagulation tests, and cardiopulmonary bypass

Abstract

Platelet function and blood coagulation were studied and correlated with the post-operative red blood cell (RBC) loss in 41 patients that underwent cardiopulmonary bypass surgery. Before and after surgery, whole blood platelet aggregation and secretion were tested with different agonists, and the platelet count, prothrombin time, and activated partial thromboplastin time measured simultaneously. Post-operatively, RBC loss in chest fluid was also calculated. Platelet aggregation and secretion with different agonists (except with ristocetin and adenosine diphosphate (ADP)) were decreased significantly after protamine and platelet-rich plasma administration. There were no significant differences in aggregation and secretion immediately after cardiopulmonary bypass compared with after platelet-rich plasma administration With ADP, adenosine triphosphate (ATP) release was decreased significantly after the platelet-rich plasma infusion compared with post-protamine. Platelet count decreased significantly during surgery and remained low after platelet-rich plasma infusion. The clotting times were increased significantly after surgery, and after platelet-rich plasma infusion, the prothrombin time decreased significantly relative to the post-protamine value, the activated partial thromboplastin time being essentially unchanged. Postoperatively, the total volume of RBC collected after 36 h was 158 +/- 13 ml and there was no significant correlation with the above parameters. We conclude that pre-operative or intra-operative whole blood lumi-aggregometry is not a predictor of post-operative blood loss in patients receiving platelet-rich plasma intra-operatively.