Comparison of Remimazolam and Sevoflurane on Perioperative Body Temperature Changes in Older Patients Undergoing Transurethral Resection of Prostate or Bladder Tumors Under General Anesthesia: A Randomized Prospective Clinical Trial.

Purpose: Perioperative hypothermia is a common complication of general anesthesia, especially in older patients undergoing transurethral resection of the prostate (TURP) or bladder tumors (TURB). Age-related thermoregulatory impairment increases vulnerability to hypothermia, and large-volume irrigation during these procedures further elevates the risk. Preclinical and clinical studies suggest that remimazolam may reduce perioperative hypothermia and shivering compared with volatile anesthetics. This study compared remimazolam and sevoflurane on perioperative body temperature (BT) changes in older patients undergoing TURP or TURB. Patients and Methods: This prospective, randomized clinical trial enrolled 84 patients aged 65-85 years undergoing TURP or TURB under general anesthesia. Patients were randomized to receive either remimazolam (n = 42) or sevoflurane (n = 42). Preoperative tympanic temperature was measured immediately before induction, and intraoperative core BT was monitored with an esophageal temperature probe. Postoperative BT was recorded using tympanic thermometry. The primary outcome was the incidence of perioperative hypothermia (BT < 36.0°C). Secondary outcomes included intraoperative decrease in BT, incidence of profound hypothermia (BT < 35.0°C), need for active warming in the PACU, postoperative nausea, vomiting and shivering, pain scores, and perioperative hemodynamic variables. Results: The change over time in BT in operating room was significantly different between 2 groups (P = 0.010). The remimazolam group exhibited significantly smaller intraoperative reductions in core BT compared to the sevoflurane group (0.83 ± 0.38°C vs 1.08 ± 0.48°C, P=0.011). The incidence of profound hypothermia occurred in the sevoflurane group (17%) and was not observed in the remimazolam group (0%) (P = 0.029). Significantly fewer patients in the remimazolam group required active warming in the PACU (19% vs 40%, P = 0.032). Hemodynamic variables and postoperative shivering rates were comparable between the groups. Conclusion: These findings suggest that remimazolam may offer thermoregulatory advantages in older surgical patients at high risk for hypothermia.