The appearance of S-100 protein in serum during and immediately after cardiopulmonary bypass surgery: A possible marker for cerebral injury

Objective: To investigate the appearance and elimination of brain-specific S-100 protein in serum during and immediately after cardiopulmonary bypass. Design: Prospective study. Participants: Twenty-nine patients undergoing elective cardiac surgery. Interventions: Twenty-seven patients were operated on for coronary artery disease; two patients had valve replacement. Serial measurements of S-100 in arterial blood during and up to 48 hours after cardiopulmonary bypass were made. Measurements and Main Results: The perioperative and postoperative course was uneventful in 25 patients, with no clinical signs of neurologic complications. S-100 was not detected before extracorporeal circulation was started. Detectable concentrations (detection limit, 0.2 mu g/L) appeared in serum after 10 minutes of perfusion and reached maximum levels, 2.43 +/- 0.3 mu g/L, at the end of bypass. The levels then declined with elimination t(1/2) of 2.2 hours. Only two patients had detectable concentrations of S-100 48 hours after the end of bypass. In four patients who developed clinical signs of cerebral injury, levels of S-100 were significantly higher at the end of bypass and 24 hours after the end of bypass. Conclusions: Cardiopulmonary bypass initiates a release of brain-specific S-100 to the systemic circulation. The release and elimination of S-100 seem to follow a reproducible pattern in patients with no signs of cerebral injury. In patients who developed cerebral injury, the concentrations of S-100 in blood were increased, thus suggesting that S-100 may be a usable marker for cerebral injury after extracorporeal circulation. Copyright (C) 1997 by W.B. Saunders Company.