Serum S-100 protein levels after pediatric cardiac operations: a possible new marker for postperfusion cerebral injury.

BACKGROUND: The release of neuron-specific astroglial S-100 protein to the cerebrospinal fluid is a marker of cerebral damage. The aim of this study was to determine the pattern of release of S-100 protein to serum after pediatric cardiac operations and extracorporeal circulation. METHODS: Sequential blood samples from 97 children (up to 16 years) were taken after induction of anesthesia, immediately after the discontinuation of extracorporeal circulation, and 5 and 15 hours after extracorporeal circulation. The children were divided into five groups including three age groups, children with Mb Down syndrome, and children undergoing circulatory arrest. RESULTS: The serum concentrations of S-100 protein before the cardiac operation were found to be highest in neonates. Children with Down syndrome, regardless of age, had basal levels comparable to those in neonates. There was an increase in S-100 protein concentration immediately after extracorporeal circulation and a multivariate regression analysis showed this difference in S-100 protein concentration to be significant with respect to age (p = 0.002), perfusion time (p < 0.001), and circulatory arrest (p < 0.001), but the difference was not significant with respect to weight, Down syndrome, and core temperature (p > 0.8). In children younger than 1 month old and after circulatory arrest, levels of S-100 protein remained high at 5 hours after extracorporeal circulation. CONCLUSION: These findings emphasize the necessity of using age-matched reference values and taking perfusion time into consideration when S-100 protein levels are evaluated with respect to cerebral postperfusion injuries in pediatric patients undergoing cardiac operations.