Thrombus formation in a staged capillary membrane oxygenator associated with a microaggregate blood filter: a scanning electron microscope study.

Blood contact at interfaces in extracorporeal devices is a source of traumas. Proteins are very rapidly adsorbed; then, depending on which proteins are left various degrees of platelet aggregation follow and thrombi develop. The scanning electron microscope reveals very instructive information on the morphology of the blood deposits which adhere to foreign surfaces. Oxygenators such as the Awad D, which is a staged one made of silicone rubber, become "thrombus invaded" after prolonged extracorporeal circulation in spite of adequate heparinization of the blood. In most cases, evaluation of membranes and devices is assessed with respect to transfer of blood gases. Careful examination of the morphology of deposits should be developed. This study shows the importance of blood flow rate, design, and materials.