The Effect of Methylprednisolone on Complement Activation during Cardiopulmonary Bypass

Abstract

A prospective randomized trial in 80 patients having heart surgery was undertaken to test the hypothesis that steroids (ST) (methylprednisolone, 30 mg/kg) would prevent or reduce complement activation during cardiopulmonary bypass (CPB) with membrane (MEM) or bubble (BUB) oxygenators. Group I patients had MEM and ST; Group II, MEM without ST; Group III, BUB and ST; Group IV, BUB without ST. Complement activation was assessed by C3a radioimmunoassay determinations obtained before, during and after CPB. When Group I was compared to Group II, there was a significant increase in C3a generation in the presence of ST. Also, when Groups I and III combined — both with ST — were compared to Groups II and IV — both without ST — a significant increase in C3a with ST was observed. In contrast, comparing MEM to BUB (Group I vs. III or II vs. IV) no significant difference in C3a was seen. Thus the hypothesis- that ST would prevent or reduce complement activation — was not confirmed and ST appears to actually increase complement activation. Also, MEM oxygenators were not associated with less activation of C3a than BUB oxygenators.