Impact of ambient temperature on postoperative cognitive dysfunction in elderly patients surgery: A seasonal comparison in tropical regions

BACKGROUND To investigate whether seasonal differences in ambient temperature affect the incidence of early postoperative cognitive dysfunction (POCD) among elderly patients undergoing laparoscopic surgery in tropical regions. Additionally, it explored the perioperative risk factors associated with early POCD following abdominal laparoscopic surgery. AIM To investigate the influence of seasonal differences in ambient temperature on POCD of elderly patients METHODS A total of 125 patients aged ≥ 65 years from Hainan Province, China, who underwent laparoscopic surgery under general anesthesia with tracheal intubation, were enrolled. All patients completed the Mini-Mental State Examination one day before surgery and on postoperative days 1, 3, and 7. A decline of ≥ 2 points from baseline was considered indicative of cognitive dysfunction. Serum levels of S100 calcium binding protein B and neuron-specific enolase were measured using enzyme-linked immunosorbent assay at three time points: Preoperatively, immediately after extubation, and 24 hours postoperatively. Perioperative clinical data were collected to identify potential risk factors for POCD. Propensity score matching (PSM) was performed (1:1, caliper = 0.03), resulting in 41 matched patient pairs between winter and summer groups. RESULTS After PSM, baseline characteristics including age, gender, body mass index, education level, comorbidities, and surgical variables were well balanced between groups. There were no significant differences in the incidence of POCD on postoperative days 1, 3, and 7 between patients undergoing laparoscopic surgery in winter vs summer. However, multivariable logistic regression revealed that surgical duration (day 1, P value = 0.049), advanced age and elevated creatinine (day 3, P value = 0.044, P value = 0.008), and hypoalbuminemia (day 3, P value = 0.042; day 7, P value = 0.015) were independently associated with early POCD. CONCLUSION Ambient temperature differences between winter and summer in tropical regions did not significantly affect the incidence of early POCD in elderly patients undergoing laparoscopic surgery. Nonetheless, age, longer surgical duration, elevated creatinine, and hypoalbuminemia emerged as key risk factors. These findings underscore the importance of perioperative optimization to reduce the risk of POCD in elderly patients, regardless of seasonal temperature variations.