Increased levels of S-100 protein after cardiac surgery with cardiopulmonary bypass and general surgery in children

The aim of this study was to evaluate changes in concentrations of the neur ospecific protein S-100 in relation to cardiac surgery with cardiopulmonary bypass (CPB) and noncardiac general surgery in children below 3 years of a ge. Seventeen children underwent surgery for congenital heart disease and a ll survived without clinical signs of neurological complications. Samples f or plasma concentrations of S-100 in these patients were taken on three occ asions in connection with surgery: before the start of surgery, after CPB a nd finally 16-20 h after CPB. In the noncardiac group of 31 children, S-100 concentrations were measured on two occasions: before surgery and during s urgery. In both groups, a significant increase in S-100 concentrations was observed during surgery, although the increase in the CPB group was signifi cantly higher than in the noncardiac group. The CPB group included four chi ldren with Down's syndrome who had higher mean S-100 concentrations on all sampling occasions compared to the remaining patients. The peak S-100 conce ntrations after cardiac surgery were related to the duration of CPB, the ti me from the termination of CPB to the first post-CPB sample, as well as mea n arterial pressure and cerebral arteriovenous lactate difference during re warming. All the children studied (Down's patients excluded) had age-depend ent plasma concentrations of S-100 measured before surgery. It can be concl uded that CPB initiates a marked but transient release of S-100 into the sy stemic circulation during open heart surgery in children who are not develo ping clinical signs of neurological sequelae.