The influence of the duration of cardiopulmonary bypass on coagulation, fibrinolysis and platelet function.

BACKGROUND: The duration of cardiopulmonary bypass (CPB) might influence blood coagulation. This appears particularly relevant in the light of new, less invasive techniques that propose smaller incisions at the expense of a possible prolongation of time on CPB. METHODS: The time-dependent effects on coagulation, fibrinolysis and platelet function were investigated in 94 patients scheduled for elective coronary artery bypass grafting. Tests on coagulation, fibrinolysis, and platelet function (flow cytometric assay of expression densities of glycoprotein IIb/IIIa and P-selection were performed the day before surgery and after completion of surgery. RESULTS: A significant correlation was found between the duration of CPB and parameters of increased coagulation, decrease of platelet counts during CPB and platelet function. Longer duration of CPB led to an increased need for transfusion of red blood cells. CONCLUSIONS: The duration of CPB affects thrombin formation as well as platelet count and function, but not the fibrinolytic system. This may prove to be a disadvantage when employing minimally invasive techniques that prolong the duration of CPB.