The systemic inflammatory response that occurs after cardiopulmonary bypass shows many changes similar to those seen in sepsis. The mechanisms for these changes have been attributed to cellular and humoral activation, such as increased secretion of cytokines and complement. The aim of our study was to investigate the cytokine pattern of pro- and anti-inflammatory cytokines in young children during and after bypass surgery. Nineteen children undergoing either septal defect correction (n = 12), or more complex surgery (n = 7), were prospectively included in this study. There were significant higher pre-operative levels of circulating cytokines in the latter group. Cardiopulmonary bypass surgery induced in both groups a rise in circulating cytokine levels and a sharp decline in the capacity of the leucocytes to secrete interleukines-6 and -8 in response to ex vivo stimulation with lipopolysaccharide. Ex vivo production of interleukine-1 receptor antagonist was slightly attenuated by the procedure.
Conclusions: The downregulation of ex vivo pro- and, to some extent, anti-inflammatory cytokine production may be a reflection of a cellular stress response, induced by anaesthesia, cardiopulmonary bypass and surgery.