Cytokine production and hemofiltration in children undergoing cardiopulmonary bypass

Multiorgan dysfunction still occurs after cardiopulmonary bypass and remains a major cause of morbidity and mortality, especially in the pediatric age group. This is consequent upon the so-called systemic inflammatory response to bypass with an increase in inflammatory mediators. Hemofiltration may be able to attenuate the effects of this response by elimination of some or all of these mediators. We undertook a prospective, randomized study to investigate the effect of hemofiltration on plasma levels of the cytokines tumor necrosis factor alpha, interleukin-8, and interleukin 6 in 18 infants and children undergoing deep hypothermic bypass. Serial plasma samples were taken before, during, and after bypass. Assay of the plasma samples revealed presence of the cytokines in a number of subjects in both groups, in some cases before operation. There were significant reductions in levels of tumor necrosis factor after hemofiltration, with no reduction noted in the group not undergoing hemofiltration. A similar difference (p < 0.05) was detected in the levels of interleukin-6 between the two groups after bypass, although this was largely due to changes in 2 subjects. Interleukin-8 was detected in a small number of subjects insufficient for statistical analysis, but with higher values in the group undergoing hemofiltration. We conclude that hemofiltration has the potential to remove cytokines from the circulation, with consequent beneficial effects.