Protein S-100 is present in extracerebral fluids before and after cardiac surgery in children

Background: Protein S-100 is found in extracerebral sources. The aim of our study was to examine the content of protein S-100 in native pericardial fluid as well as in postoperative extracerebral fluids after cardiac surgery in children. Methods: We conducted a prospective study in 90 children measuring protein S-100 concentration in pericardial fluid directly after opening the pericardial sac before starting with cardiac surgery. Postoperatively, we examined pleural, peritoneal and pericardial fluid. Results: Pericardial fluid sampled directly after opening the pericardial sac has a protein S-100 content of 3.2 (1.3-5.4) μg/L. Postoperatively, protein S-100 content was 0.89 (0.56-2.6) μg/L in pleural effusion, 0.14 (0.1-1.1) μg/L in peritoneal fluid and 2.75 (2.2-24.4) μg/L in pericardial fluid. The protein S-100 concentration in pericardial fluid before and after cardiac operation did not differ significantly. Pericardial protein S-100 concentrations were significantly higher than pleural and peritoneal protein S-100 concentrations. Conclusions: Protein S-100 is present in extracerebral fluids before and after cardiac surgery in children. The time point of fluid withdrawal after the operation did not influence the protein S-100 concentration.