Influence of long-term plasmapheresis on blood coagulation

The influence of serial, double plasmapheresis on blood coagulation was evaluated in two groups of plasma donors that had undergone from 3 to 306 plasmapheresis sessions. Averages of 375 and 660 ml of plasma, respectively, were harvested weekly from the donors. No statistically significant changes were observed in platelet count, activities of factor V and factor VIII, fibrinogen, plasminogen, alpha 2-macroglobulin, antithrombin III and prothrombin time, irrespectively of the frequency and the number of the plasmapheresis sessions. The concentration of alpha 1-antitrypsin was already increased after seven plasmapheresis sessions in both groups of donors. The kaolin-cephalin clotting time was progressively shortened with the increasing volume of harvested plasma (p less than 0.05) and the thrombin time was prolonged (p less than 0.05).