Serum S100B and hypothermic circulatory arrest in adults

Background. Cerebral injury is the most important complication of cardiac o perations with cardiopulmonary bypass. Prolonged total circulatory arrest ( TCA) can expose patients to an even greater risk of cerebral injury. We sou ght to detect the degree of cerebral injury in adults who had thoracic aort ic operations with TCA by measuring S100B protein, which is released into t he circulation after cerebral injury. Methods. Serial measurements of S100B protein, a highly specific serum mark er of astroglial damage, were performed in 26 patients who had complex aort ic operations, of whom 13 required cardiopulmonary bypass alone (for aortic root replacement), and in 13 patients who required an additional period of TCA (for type A aortic dissections and arch aneurysms). Blood samples were taken preoperatively, at skin closure, and 5 and 24 hours postoperatively. Results. There were significant increases in serum S100B concentrations in all patients, and peak levels occurred at skin closure. The magnitude of th e increase in S100B was significantly greater at all postoperative time poi nts and persisted longer in the TCA group. There was a significant correlat ion between the duration of the TCA and S100B concentration at 5 hours (r = 0.66, p 0.01) and 24 hours (r = 0.63, p = 0.02) postoperatively. Conclusions. S100B levels were higher in all patients who had complex aorti c operations and were significantly greater in patients requiring a period of TCA. The duration of the TCA period correlated with S100B levels 5 hours and at 24 hours postoperatively. Circumstantial evidence, in accordance wi th other studies, suggests that S100B protein is a marker for cerebral inju ry during cardiac operations. (C) 1999 by The Society of Thoracic Surgeons.