BIOCOMPATIBILITY IN HEMAPHERESIS - BLOOD-COAGULATION

Hemapheresis may influence the coagulation system with effects of activation and dilution. Dilution can lead to reduced levels of platelets, fibrinogen and antithrombin III. Activation initially causes increased clotting activity, but the consumption of the activated factors generally induces a subsequent phase of hypocoagulability. In the donor, apheresis diminishes platelet count and function, as well as the levels of many other clotting factors. Depletion of fibrinogen and antithrombin III are less transient than others because their rates of synthesis are lower. In spite of the wide variety in hemapheretic procedures, all of them (or at least, those that are the most commonly used) are associated with similar activation phenomena, that appear to be mediated by the formation of a fibrinogen layer on the artificial surfaces of the circuitry.