Perioperative Medicine  |   May 2018
Effects of Ambient Temperature and Forced-air Warming on Intraoperative Core Temperature: A Factorial Randomized Trial
Author Notes
  • From the Departments of Anesthesia (L.P., Y.H.), Hepatic Surgery (Y.X., Y.Z., X.S.), and Thoracic Surgery (X.Z., S.L.), Peking Union Medical College Hospital, Beijing, China; Outcomes Research Consortium, Cleveland, Ohio (L.P., Y.H.); and the Departments of Quantitative Health Sciences (G.M., E.J.M.) and Outcomes Research, Anesthesiology Institute (G.M., E.J.M., D.I.S.), Cleveland Clinic, Cleveland, Ohio.
  • Corresponding article on page 871.
    Corresponding article on page 871.×
  • Supplemental Digital Content is available for this article. Direct URL citations appear in the printed text and are available in both the HTML and PDF versions of this article. Links to the digital files are provided in the HTML text of this article on the Journal’s Web site (www.anesthesiology.org).
    Supplemental Digital Content is available for this article. Direct URL citations appear in the printed text and are available in both the HTML and PDF versions of this article. Links to the digital files are provided in the HTML text of this article on the Journal’s Web site (www.anesthesiology.org).×
  • Submitted for publication March 17, 2017. Accepted for publication December 21, 2017.
    Submitted for publication March 17, 2017. Accepted for publication December 21, 2017.×
  • Address correspondence to Dr. Sessler: Department of Outcomes Research, Anesthesiology Institute, Cleveland Clinic, 9500 Euclid Ave—P77, Cleveland, Ohio 44195. DS@OR.org. Information on purchasing reprints may be found at www.anesthesiology.org or on the masthead page at the beginning of this issue. Anesthesiology’s articles are made freely accessible to all readers, for personal use only, 6 months from the cover date of the issue.
Article Information
Perioperative Medicine / Clinical Science / Cardiovascular Anesthesia / Central and Peripheral Nervous Systems / Endocrine and Metabolic Systems / Gastrointestinal and Hepatic Systems / Infectious Disease / Pain Medicine / Patient Safety / Pediatric Anesthesia / Pharmacology / Respiratory System / Technology / Equipment / Monitoring / Quality Improvement / Opioid
Perioperative Medicine   |   May 2018
Effects of Ambient Temperature and Forced-air Warming on Intraoperative Core Temperature: A Factorial Randomized Trial
Anesthesiology 5 2018, Vol.128, 903-911. doi:10.1097/ALN.0000000000002099
Anesthesiology 5 2018, Vol.128, 903-911. doi:10.1097/ALN.0000000000002099
Abstract

Background: The effect of ambient temperature, with and without active warming, on intraoperative core temperature remains poorly characterized. The authors determined the effect of ambient temperature on core temperature changes with and without forced-air warming.

Methods: In this unblinded three-by-two factorial trial, 292 adults were randomized to ambient temperatures 19°, 21°, or 23°C, and to passive insulation or forced-air warming. The primary outcome was core temperature change between 1 and 3 h after induction. Linear mixed-effects models assessed the effects of ambient temperature, warming method, and their interaction.

Results: A 1°C increase in ambient temperature attenuated the negative slope of core temperature change 1 to 3 h after anesthesia induction by 0.03 (98.3% CI, 0.01 to 0.06) °Ccore/(h.°Cambient) (P < 0.001), for patients who received passive insulation, but not for those warmed with forced-air (–0.01 [98.3% CI, –0.03 to 0.01] °Ccore/[h.°Cambient]; P = 0.40). Final core temperature at the end of surgery increased 0.13°C (98.3% CI, 0.07 to 0.20; P < 0.01) per degree increase in ambient temperature with passive insulation, but was unaffected by ambient temperature during forced-air warming (0.02 [98.3% CI, –0.04 to 0.09] °Ccore/°Cambient; P = 0.40). After an average of 3.4 h of surgery, core temperature was 36.3° ± 0.5°C in each of the forced-air groups, and ranged from 35.6° to 36.1°C in passively insulated patients.

Conclusions: Ambient intraoperative temperature has a negligible effect on core temperature when patients are warmed with forced air. The effect is larger when patients are passively insulated, but the magnitude remains small. Ambient temperature can thus be set to comfortable levels for staff in patients who are actively warmed.