Nudtapod Rutanaburee, MD¹ , Wanida Chongarunngamsang, MD¹ , Jutarat Luanpholcharoenchai, MD¹ , Nattasit Jivaganont, MD¹ , Phuntanit Chanta, RN¹ , Pimpira Ponkla, RN¹

Background: Perioperative hypothermia is a frequent complication of anesthesia, associated with delayed recovery, cardiovascular stress, infection, and coagulopathy. Current guidelines recommend active prewarming devices for at least 30 minutes before anesthesia induction; however, this duration is often impractical in routine clinical settings. Evidence suggests shorter prewarming may be beneficial, though data in gynecologic surgery with combined regional and general anesthesia are limited.

Objective: To compare the change in body temperature after anesthesia induction between patients receiving 5 minutes of prewarming and those without prewarming. Secondary objectives were to evaluate the incidence of intraoperative hypothermia, postoperative shivering, surgical site infections, and cardiovascular adverse effects.

Materials and Methods: A prospective randomized controlled trial was conducted in 39 patients undergoing elective gynecologic abdominal surgery with combined general-regional anesthesia. Patients were randomized to receive either 5 minutes of prewarming with an underbody forced-air blanket at 43℃ or no prewarming. Core temperature was measured using the 3M™ Spot-On™ system 60 minutes following anesthesia induction. Data were specifically recorded at induction and every 5 minutes until the conclusion of surgery. Statistical analyses were performed with significance set at p-value less than 0.05.

Results: The prewarming group demonstrated a significantly smaller decrease in body temperature at 60 minutes (0.48℃ vs. 0.92℃, mean difference –0.44℃, 95% CI –0.67 to –0.20, p<0.001). However, there were no significant differences in the incidence of intraoperative hypothermia, postoperative shivering, surgical site infections, or cardiovascular complications.

Conclusion: Brief prewarming with a forced-air underbody blanket reduced early intraoperative temperature decline but did not decrease the overall incidence of hypothermia or related complications. Short-duration prewarming may provide limited thermal benefit, though further studies are required to establish its clinical significance.

Received 27 August 2025 | Revised 6 May 2026 | Accepted 22 May 2026

J Med Assoc Thai 2026;109(10):808-15

DOI: 10.35755/jmedassocthai.2026.10.03571