Factors associated with postoperative shivering in patients with maintained core temperature after surgery

Abstract Background Postoperative shivering is mainly associated with low body temperature. However, postoperative shivering can develop even at normal or high core temperatures. This study aimed to investigate the factors associated with postoperative shivering in patients with maintained core temperature after surgery. Methods This retrospective study involved 537 patients who had undergone radical surgery for pancreatic cancer under general anesthesia from January 2013 to December 2023. The final analysis included 441 patients whose core temperatures after surgery were ≥ 36.5℃. Logistic regression analysis was performed to estimate the odds ratio (OR) of the incidence of postoperative shivering. Results Postoperative shivering occurred in 119 patients. After multivariable-adjusted logistic regression, postoperative shivering was significantly associated with patient age (per 1 year increase; OR = 0.98; 95% confidence interval [CI]: 0.96–0.996; p = 0.02), operation time (per 30 min increase; OR = 1.10; 95% CI: 1.01–1.19; p = 0.03), postoperative core temperature (restricted cubic spline, p = 0.001), postoperative peripheral temperature (restricted cubic spline, p = 0.001), effect site fentanyl concentration at extubation (OR = 0.66; 95% CI: 0.24–0.99; p = 0.049), and acetaminophen use (OR = 0.32; 95% CI: 0.18–0.58; p