Correlation of S100B level and postoperative cognitive dysfunction (POCD) events among patients with ear, nose and throat (ENT) surgeries with controlled hypotension

Introduction: Controlled hypotension is one of the techniques applied to several microscopic ear, nose, and throat (ENT) surgeries. However, this technique has risks and complications, which result in impaired perfusion and oxygenation of organs including the brain that could trigger the postoperative cognitive dysfunction (POCD). Damage that occurs in brain cells can trigger the secretion of biomarker proteins in the blood, one of which is S100B which can indicate nerve damage in the intra and postoperative period. This study aimed to analyze the correlation between S100B protein level and the incidence of POCD in patients who received ENT surgeries with controlled hypotension. Methods: A cross-sectional study was conducted among patients that underwent elective ENT surgeries at Dr. Soetomo General Academic Hospital, Surabaya, from July to August 2022. Cognitive function was assessed using Mini-mental State Examination (MMSE) at 12 hours before and 2 and 24 hours after surgery. The level of S100B was measured using enzyme-linked immunosorbent assay (ELISA) 12 hours prior surgery and 30 minutes post-surgery. Results: A total of 31 patients were recruited in the study, including a mean age of 31.7 years. The mean S100B levels in POCD patients pre- and postoperative were 311.97 ng/L, and 415.34 ng/L, respectively. In non-POCD patients, the mean levels of S100B pre and postoperative were 436.90 ng/L, and 444.29 ng/L, respectively. There were 3 (9.7%) patients experienced POCD. Our data suggested there was a significant difference between preoperative and postoperative S100B levels in the groups of patients with POCD (103.37ng/L) and non-POCD (7.38 ng/L) (p<0.001). Patients that experienced POCD had significantly increased S100B compared to those who did not. Conclusion: There is a correlation between changes of S100B levels and the incidence of POCD in patients undergoing ENT surgeries with controlled hypotension.