Hematologic responses to prolonged extracorporeal circulation (ECC) with microporous membrane devices.

Twenty-four to 48 hr veno-arterial bypass with microporous membrane oxygenators causes moderate progressive thrombocytopenia associated with decreased platelet function, no significant change in clotting factors, fibrinogen, or the fibrinolytic system, and minimal change in white blood count, differential, and plasma hemoglobin. These effects are identical to those seen in previous studies following the same protocol with solid silicone rubber membrane oxygenators. Microporous membrane is suitable for prolonged extracorporeal support systems. This study suggests that the deleterious effects of a direct blood gas interface are caused by continuous renewal of the surface rather than the nature of the interface itself.