BIOCOMPATIBILITY IN HEMAPHERESIS - BLOOD-COAGULATION

Hemapheresis may influence the coagulation system with effects of acti vation and dilution. Dilution can lead to reduced levels of platelets, fibrinogen and antithrombin III. Activation initially causes increase d clotting activity, but the consumption of the activated factors gene rally induces a subsequent phase of hypocoagulability. In the donor, a pheresis diminishes platelet count and function, as well as the levels of many other clotting factors. Depletion of fibrinogen and antithrom bin III are less transient than others because their rates of synthesi s 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 a ssociated with similar activation phenomena, that appear to be mediate d by the formation of a fibrinogen layer on the artificial surfaces of the circuitry.