Preventing inadvertent perioperative hypothermia

Abstract

Background: 25-90% of all patients undergoing elective surgery suffer from inadvertent postoperative hypothermia, i.e., a core body temperature below 36°C. Compared to normothermic patients, these patients have more frequent wound infections (relative risk [RR] 3.25, 95% confidence interval [CI] 1.35-7.84), cardiac complications (RR 4.49, 95% CI 1.00-20.16), and blood transfusions (RR 1.33, 95% CI 1.06-1.66). Hypothermic patients feel uncomfortable, and shivering raises oxygen consumption by about 40%.

Methods: This guideline is based on a systematic review of the literature up to and including October 2012 and a further one from November 2012 to August 2014. The recommendations were developed and agreed upon by representatives of five medical specialty societies in a structured consensus process.

Results: The patient's core temperature should be measured 1-2 hours before the start of anesthesia, and either continuously or every 15 minutes during surgery. Depending on the nature of the operation, the site of temperature measurement should be oral, naso-/oropharyngeal, esophageal, vesical, or tympanic (direct). The patient should be actively prewarmed 20-30 minutes before surgery to counteract the decline in temperature. Prewarmed patients must be actively warmed intraoperatively as well if the planned duration of anesthesia is longer than 60 minutes (without prewarming, 30 minutes). The ambient temperature in the operating room should be at least 21°C for adult patients and at least 24°C for children. Infusions and blood transfusions that are given at rates of >500 mL/h should be warmed first. Perioperatively, the largest possible area of the body surface should be thermally insulated. Emergence from general anesthesia should take place at normal body temperature. Postoperative hypothermia, if present, should be treated by the administration of convective or conductive heat until normothermia is achieved. Shivering can be treated with medications.

Conclusion: Inadvertent perioperative hypothermia can adversely affect the outcome of surgery and the patient's postoperative course. It should be actively prevented.

Figures

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Development process for the guideline “Preventing inadvertent perioperative hypothermia”

eFigure 1

Guideline research for the guideline “Preventing inadvertent perioperative hypothermia” • NICE guideline 2008 ([3], United Kingdom)—primary source guideline • Joanna Briggs Institute Guideline 2010 ([4], Australia) • Canadian and American colleges of surgery 2009 (5) • ASPAN guideline 2010, 2nd ed ([6], USA)

eFigure 2

Sample literature search for the section “intraoperative patient warming” for the guideline “Preventing inadvertent perioperative hypothermia” Search strings: – “hypothermia”[MeSH Terms] OR “hypothermia”[All Fields]) AND forced-air[All Fields] AND warming[All Fields]: 178 abstracts – “hypothermia”[MeSH Terms] OR “hypothermia”[All Fields]) AND resistive[All Fields] AND (“heating”[MeSH Terms] OR “heating”[All Fields]): 19 abstracts – “hypothermia”[MeSH Terms] OR “hypothermia”[All Fields]) AND intraoperative[All Fields] AND warming[All Fields]: 254 abstracts Number of studies finally remaining for evaluation: 41