Effect of Intraoperative Forced-air Warming on Perioperative Hypothermia and Related Complications in Patients Undergoing Total Knee Arthroplasty: A Historical Control Study

This single-center historical control study was conducted at Shanghai 6th People's Hospital between May 2018 and December 2018 to evaluate the effectiveness of intraoperative forced-air warming for preventing perioperative hypothermia in patients undergoing total knee arthroplasty (TKA).

A total of 240 patients undergoing primary unilateral TKA were enrolled and divided into two groups according to the study period. Patients enrolled between May 2018 and August 2018 were assigned to the historical control group and received routine passive warming measures, including warmed intravenous fluids, warmed irrigation fluids, operating room temperature control, and cotton blanket coverage. Patients enrolled between September 2018 and December 2018 were assigned to the intervention group and received additional active warming using a forced-air warming system during the perioperative period.

The forced-air warming system was initiated 30 minutes before anesthesia induction and continued until transfer to the post-anesthesia care unit (PACU). Core temperature was continuously monitored using a temperature-sensing urinary catheter.

The primary outcomes included perioperative core temperature changes and the incidence of inadvertent perioperative hypothermia, defined as core temperature below 36°C at any perioperative time point. Secondary outcomes included postoperative shivering, emergence agitation, anesthetic recovery time, blood loss, postoperative complications, and safety outcomes including skin burns and surgical site infection.

This study was approved by the Ethics Committee of Shanghai 6th People's Hospital (Approval No. 05.12.19035). Written informed consent was obtained from all participants before enrollment.