Acute-phase responses to cardiopulmonary bypass in children weighing less than 10 kilograms

Background. Cardiopulmonary bypass induces a systemic inflammatory response. This study investigated, in a pediatric population, cytokine-induced responses and their potential modification by intraoperative steroid administration. Methods. Markers of the acute-phase response were measured perioperatively in 24 children weighing less than 10 kg undergoing cardiac operations. Those having operations with cardiopulmonary bypass were randomized to receive either no steroid (group I, n=8) or 10 mg/kg methylprednisolone in the pump prime (group II, n=10); patients undergoing nonbypass procedures were controls (group III, n=6). Results. In all groups, plasma interleukin-6 level was elevated ( p p r s = 0.76; p Conclusions. This study demonstrated a marked acute-phase response to operation; the greater response to procedures with cardiopulmonary bypass was abrogated by intraoperative steroid administration. The importance of interleukin-6 as an inducer of acute phase proteins after bypass is supported by its association with C-reactive protein levels, but other factors must be important in the induction of pyrexia.