Inflammatory mediators in adults undergoing cardiopulmonary bypass: Comparison of centrifugal and roller pumps

Background. The nonocclusive centrifugal pump is used for cardiopulmonary bypass (CPB) and mechanical cardiac assistance. This study examined its impact on proinflammatory cytokine release. Methods. Forty-one patients undergoing elective coronary artery bypass grafting were randomized prospectively to either a standard roller pump group (n = 21) or a centrifugal vortex pump group (n = 20) for CPB. The two groups were well matched in age, sex, severity of disease, and duration of CPB and aortic cross-clamping. Plasma levels of the cytokines tumor necrosis factor-alpha; interleukin-1 beta, interleukin-6, and interleukin-8, as well as terminal complement, neutrophil counts, and leukocyte elastase, were analyzed before, during, and after CPB. Results. In both groups, traces of tumor necrosis factor-cu were observed infrequently and interleukin-1 beta was not detected. Plasma levels of interleukin-6 and interleukin-8 increased during and after CFB, reaching a peak at 2 hours after protamine administration in both groups before returning toward baseline at 24 hours. The release of interleukin-6 was significantly greater in the centrifugal group (p < 0.05), whereas the interleukin-8 concentration did not differ between the groups throughout the study period. Levels of terminal complement increased in both groups perioperatively, reaching a peak 30 minutes after protamine administration, whereas neutrophil counts and elastase peaked 2 hours after protamine administration. Plasma terminal complement, neutrophil counts, and elastase release were significantly higher in the centrifugal group (p < 0.05). Peak terminal complement correlated (r = 0.64, p < 0.01) with peak elastase in the centrifugal group only. Conclusions. This study confirms the proinflammatory nature of CPB in adults and demonstrates that use of the centrifugal pump induces a greater systemic inflammatory response than use of the standard roller pump. (C) 1998 by The Society of Thoracic Surgeons.