Abstract
BACKGROUND AND AIMS: Postoperative delirium (POD) is a prevalent and serious complication in elderly patients undergoing surgery, contributing to prolonged hospital stays and increased morbidity. While the exact mechanism remains elusive, growing evidence suggests the involvement of the cholinergic system in delirium pathogenesis. MATERIAL AND METHODS: This observational study aimed to investigate the association between cholinergic biomarkers and POD in elderly patients under regional anesthesia. Eighty-seven patients scheduled for surgery under regional anesthesia were enrolled. Baseline cognitive function was assessed using the Mini-Mental State Examination preoperatively. POD assessment was conducted in the postoperative care unit on days 1, 2, 3, and 7 by using the Confusion Assessment Method. Severity of delirium was evaluated using the Memorial Delirium Assessment Scale. Plasma levels of choline acetyltransferase (ChAT), acetylcholinesterase (AChE), and butyrylcholinesterase (BuChE) were measured preoperatively and 24 hours postoperatively. RESULTS: Fourteen patients were diagnosed with POD. Compared to the non-POD group, the POD group exhibited significantly higher levels of ChAT and lower levels of AChE and BuChE both pre- and postoperatively (P < 0.0001). Receiver operating characteristic (ROC) curve analysis revealed that AChE, BuChE, and ChAT concentrations had high diagnostic values for POD, with BuChE being the most sensitive but least specific among the three markers. CONCLUSIONS: This study concludes that alterations in postoperative activity of AChE, BuChE, and ChAT are associated with the development of POD in elderly patients undergoing surgery under regional anesthesia. BuChE activity showed the greatest diagnostic value among the cholinergic biomarkers assessed. These findings underscore the potential importance of cholinergic dysfunction in POD pathogenesis and highlight the diagnostic utility of assessing cholinergic biomarkers in predicting POD risk.