The Role of C-Reactive Protein as a Biomarker for Postoperative Delirium Following Cardiac and Neurosurgical Surgery: A Retrospective Analysis

<b>Background/Objectives</b>: The increasing number and complexity of cardiac and neurosurgical procedures underscore the importance of effective perioperative care. One of the most serious postoperative complications is delirium, which prolongs hospitalization, increases treatment costs, worsens rehabilitation outcomes, and increases mortality. Identifying biomarkers that predict delirium can improve patient outcomes. The aim of this study was to assess the relationship between C-reactive protein (CRP) levels and the incidence of postoperative delirium in patients after cardiac and neurosurgical procedures hospitalized in the intensive care unit. <b>Methods:</b> A retrospective study was conducted on 408 patients (202 undergoing cardiac surgery and 206 undergoing neurosurgery) who underwent surgery between April 2024 to the end of August 2024. Medical records were reviewed for the occurrence of delirium assessed using the Confusion Assessment Method-Intensive Care Unit scale (CAM-ICU), its severity assessed using the Confusion Assessment Method-Intensive Care Unit 7 (CAM-ICU-7), and laboratory test results, with particular emphasis on C-reactive protein levels. CRP levels were measured on postoperative days 1 and 2. <b>Results:</b> Postoperative delirium was noted in both groups, more frequently in patients with elevated CRP levels, indicating an active inflammatory process. In the neurosurgical group, episodes of severe delirium occurred primarily after laminectomy, whereas in the cardiac surgery group, they were most common after coronary artery bypass grafting (CABG). <b>Conclusions:</b> Elevated CRP levels are associated with a higher risk of postoperative delirium. Monitoring inflammatory parameters and implementing early preventive measures may improve treatment outcomes and shorten hospital stays. Further prospective studies using standardized diagnostic tools are necessary.