BLOOD - ARTIFICIAL SURFACE INTERACTIONS DURING CARDIOPULMONARY BYPASS - A COMPARATIVE-STUDY OF 4 OXYGENATORS

Evaluation of the biocompatibility of four different types of oxygenator (bubble, membrane, hollow fibre and 'hybrid') was performed on 26 patients undergoing cardiopulmonary bypass during elective coronary surgery. More platelet derangement and an increased degree of hemolysis, revealed by higher plasmatic concentration of beta-thromboglobulin, platelet factor 4 and plasmatic free hemoglobin (p<0.05), was seen when using the bubble oxygenator. Damage to blood cells was minimal with the membrane oxygenator while the 'hybrid' and the hollow fibre oxygenators proved to rank at an intermediate level. Complement activation at the beginning of the cardiopulmonary bypass occured via the alternative pathway as demonstrated by C3a [(des arg]) increase (up to nine times) without a concomitant elevation of C4a[(des arg.]) Cardiopulmonary bypass complement activation was quantitatively similar with all the oxygenators. A further activation via the classical pathway occurred in all the patients after protamine injection. Consistent differences as far as clinical and biological effects exist among the various commercially available cardiopulmonary bypass apparatus; our study provides guidelines for the evaluation and selection of devices which might reduce postoperative sequelae.