Related Experiment Video
Updated: Mar 16, 2026
Esophageal Heat Transfer for Patient Temperature Control and Targeted Temperature Management
Published on: November 21, 2017
A randomized trial of prewarming on patient satisfaction and thermal comfort in outpatient surgery
Zohaib Akhtar1, Brian D Hesler2, Alexa N Fiffick3
1Clinical Research Fellow, Department of Outcomes Research, Anesthesiology Institute, Cleveland Clinic, Cleveland, OH.
Study Objective:
To test the primary hypothesis that forced-air prewarming improves patient satisfaction after outpatient surgery and to evaluate the effect on core temperature and thermal comfort.
Design:
Prospective randomized controlled trial.
Setting:
Preoperative area, operating room, and postanesthesia care unit.
Patients:
A total of 115 patients aged 18 to 75 years with American Society of Anesthesiologists status <4 and body mass index of 15 to 36kg/m(2) who were undergoing outpatient surgery (duration <4 hours).
Interventions:
Patients were randomized to active prewarming with a Mistral-Air warming system initially set to 43°C or no active prewarming. All patients were warmed intraoperatively.
Measurements:
Demographic and morphometric characteristics, perioperative core temperature, ambient temperature, EVAN-G satisfaction score, thermal comfort via visual analog scales.
Main Results:
Data from 102 patients were included in the final analysis. Prewarming did not significantly reduce redistribution hypothermia, with prewarmed minus not prewarmed core temperature differing by only 0.18°C (95% confidence interval [CI], -0.001 to 0.37) during the initial hour of anesthesia (P=.052). Prewarming increased the mean EVAN-G satisfaction score, although not significantly, with an overall difference (prewarmed minus not prewarmed) of 5.6 (95% CI, -0.9 to 12.2; P=.09). Prewarming increased thermal comfort, with an overall difference of 6.6 mm (95% CI, 1.0-12.9; P=.02).
Conclusion:
Active prewarming increased thermal comfort but did not significantly reduce redistribution hypothermia or improve postoperative patient satisfaction.
