[Improvement of extracorporeal circulation on the basis of anaphylatoxin levels, with special reference to oxygenation mechanisms and plasma denaturation by oxygen bubbling].

Complement activation was evaluated in 76 patients undergoing cardiopulmonary bypass (CPB) with particular reference to anaphylatoxin levels. These patients were divided into membrane (MOG) and bubble oxygenator groups (BOG). The influence of primed homologous to circulating autologous blood volume (H/A) ratio was also examined. Each group was further divided into two subgroups: one was primed with homologous whole blood, and the other with fresh homologous concentrated red cells (CRC) and human albumin. C4a slowly increased during CPB in both groups, maintaining slightly higher levels in the BOG than in the MOG. A marked initial rise was observed in the BOG with high H/A ratios. C3a increased more steeply in the BOG than in the MOG. C5a levels in the BOG were higher than in the MOG. The influence of the H/A ratio was milder in the MOG than in the BOG. In the BOG, the anaphylatoxin levels in the group primed with CRC and human albumin were slightly lower than in the group primed with whole blood. However, anaphylatoxin levels rose most steeply in cyanotic patients even though they were perfused with a membrane oxygenator. In experimental studies using 20 monkeys (Macaca fascicularis), continuous intraaortic infusion with O2 bubbled autologous blood increased C4a and C3a levels, while autologous blood extracorporeally contacted with nylon increased C3a levels alone. C4a and C3a levels were unchanged by infusion with O2 microbubbles. In vitro studies revealed that human immunoglobulin denatured by O2 bubbling produced C4a, C3a, and C5a in a dose dependent manner, although human albumin treated identically as human immunoglobulin did not produce them.(ABSTRACT TRUNCATED AT 250 WORDS)