Hypothermia (body temperature <36 °C) is present in the postoperative period in 26% to 90% of all patients who have undergone elective surgery (1). The risk of hypothermia is particularly high in patients over 60 years of age with poor nutritional status and pre-existing disease that impairs thermoregulation (e.g., diabetes mellitus with polyneuropathy) and in those who have had major or lengthy surgery. Lower temperatures in the operating room also increase the risk of hypothermia: the lower the temperature, the higher the risk.

If hypothermia does occur, the relative risk of severe complications such as impaired wound healing is 3.25 (95% confidence interval [CI] 1.35 to 7.84) compared to normothermia; for cardiac disorders it is 4.49 (95% CI 1.00 to 20.16), and for increased bleeding with blood transfusions it is 1.33 (95% CI 1.06 to 1.66) (2). Against this background, the existing evidence on preventing, recognizing, and treating perioperative hypothermia demands to be turned into recommendations for practice. This was the objective of the first German-language interdisciplinary S3 guideline, developed under the auspices of the German Society of Anaesthesiology and Intensive Care Medicine (DGAI, Deutsche Gesellschaft fur Anasthesiologie und Intensivmedizin), together with the German Surgical Society (DGCH, Deutsche Gesellschaft fur Chirurgie), the German Society of Pediatric Surgery (DGKIC, Deutsche Gesellschaft fur Kinderchirurgie), the German Society for Specialist Nursing and Ancillary Medical Staff (DGF, Deutsche Gesellschaft fur Fachkrankenpflege und Funktionsdienste), and the Austrian Society of Anesthesiology, Resuscitation, and Intensive Care Medicine (OGARI, Osterreichische Gesellschaft fur Anasthesiologie, Reanimation und Intensivmedizin) (Box). This article presents the main principles of the guideline. For further detail, the reader is referred to the long version ([3], in German).

Box
Members of the guideline group responsible for development of the guideline “Preventing inadvertent perioperative hypothermia”


German Society of Anaesthesiology and Intensive Care Medicine

(DGAI, Deutsche Gesellschaft fur Anasthesiologie und Intensivmedizin)


Prof. Dr. med. Berthold Bein (Hamburg)*1*2


Prof. Dr. med. Anselm Brauer (Gottingen)*1*2


PD Dr. med. Jan Hocker (Kiel)*1*2


PD Dr. med. Ernst-Peter Horn (Pinneberg)*1*2


PD Dr. med. Karl-Peter Ittner (Regensburg)*1*2


Prof. Dr. med. Alexander Torossian (Marburg)*1*2 – Coordinator


Prof. Dr. med. Wolfgang Weyland (Dusseldorf)*2


Prof. Dr. med. Hinnerk Wulf (Marburg)




German Surgical Society

(DGCH, Deutsche Gesellschaft fur Chirurgie)


Prof. Dr. med. Ernst Klar (Rostock)




German Society of Pediatric Surgery

(DGKIC, Deutsche Gesellschaft fur Kinderchirurgie)


Prof. Dr. med. Peter Schmittenbecher (Karlsruhe)*2




German Society for Specialist Nursing and Ancillary Medical Staff

(DGF, Deutsche Gesellschaft fur Fachkrankenpflege und Funktionsdienste)


Tillmann Muller-Wolff (Reutlingen)


Ina Welk (Kiel)*2




Austrian Society of Anesthesiology, Resuscitation, and Intensive Care Medicine (OGARI, Osterreichische Gesellschaft fur Anasthesiologie, Reanimation und Intensivmedizin)


PD Dr. med. Oliver Kimberger (Wien)




Swiss Society of Anesthesiology and Resuscitation

(SGAR, Schweizerische Gesellschaft fur Anasthesiologie und Reanimation)


Prof. Dr. med. Robert Greif (Bern) – not mandated





*1member of steering group; *2authors with chapter responsibility; bold: lead author

Preventing inadvertent perioperative hypothermia.

Background
Hypothermia, defined as a core body temperature less than 36°C (96.8°F), is a relatively common occurrence in the unwarmed surgical patient. A mild degree of perioperative hypothermia can be associated with significant morbidity and mortality. A threefold increase in the frequency of surgical site infections is reported in colorectal surgery patients who experience perioperative hypothermia. As part of the Surgical Care Improvement Project, guidelines aim to decrease the incidence of this complication.

Unintended Perioperative Hypothermia

Summary
The aim of our study was to evaluate the performance of different durations of active pre-operative skin-surface warming (pre-warming) to prevent peri-operative hypothermia and postoperative shivering. We randomly assigned 200 patients, scheduled for surgery of 30–90 min under general anaesthesia, to receive passive insulation or forced-air skin surface warming for 10, 20 or 30 min. Body temperature was measured at the tympanic membrane. Shivering was graded by visual inspection. There were significant differences in changes of core temperature between the non-pre-warmed group and all the pre-warmed groups (p < 0.00001), but none between the three pre-warmed groups (p = 0.54). Without pre-warming, 38/55 (69%) patients became hypothermic (< 36 °C) at the end of anaesthesia, whereas only 7/52 (13%), 3/43 (7%) and 3/50 (6%) patients following 10, 20 or 30 min pre-warming, respectively, became hypothermic (p < 0.001 vs no pre-warming). Shivering was observed in 10 patients without, and in three, three and one patients with pre-warming in the respective groups (p = 0.02). Pre-warming of patients for only 10 or 20 min before general anaesthesia mostly prevents hypothermia and reduces shivering.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-2044.2012.07073.x

The effect of short time periods of pre-operative warming in the prevention of peri-operative hypothermia.

Update to the Centers for Disease Control and Prevention and the Healthcare Infection Control Practices Advisory Committee Guideline for the Prevention of Surgical Site Infection (2017): A summary, review, and strategies for implementation.

All patients undergoing surgery are at risk of developing hypothermia; up to 70% develop hypothermia perioperatively. Inadvertent hypothermia is associated with complications such as impaired wound healing, increased blood loss, cardiac arrest and increased risk of wound infection. Anaesthesia increases the risk as the normal protective shivering reflex is absent. Ambient temperature also has a major effect on the patient's body temperature. Prevention of hypothermia not only reduces the incidence of complications, but patients also experience a greater level of comfort, and avoid postoperative shivering and the unpleasant sensation of feeling cold. Nurses should be aware of the risks of hypothermia so that preventative interventions can be employed to minimize the risk of hypothermia. Preoperative assessment is essential to enable identification of at-risk patients. Simple precautionary measures initiated by nurses can considerably reduce the amount of heat lost, minimize the risk of associated complications and ultimately improve patients' short- and long-term recovery. Minimizing skin exposure, providing adequate bed linen for the transfer to theatre and educating patients about the importance of keeping warm perioperatively are all extremely important. It is also worth considering using forced-air warmers preoperatively as research suggests that initiating active warming preoperatively may be successful in preventing hypothermia during the perioperative period.

Prevention of inadvertent perioperative hypothermia.

https://www.jopan.org/article/S1089-9472(10)00412-0/pdf

ASPAN's evidence-based clinical practice guideline for the promotion of perioperative normothermia: second edition.

http://www.or.org/files/ASPAN%20Temp%20Guidelines.pdf

ASPAN's evidence-based clinical practice guideline for the promotion of perioperative normothermia.

Where does capnography fit into the PACU

https://www.jopan.org/article/S1089-9472(10)00382-5/pdf

Barbara Godden

Papers

ASPAN's evidence-based clinical practice guideline for the promotion of perioperative normothermia: second edition.

ASPAN's evidence-based clinical practice guideline for the promotion of perioperative normothermia.

Where does capnography fit into the PACU

Postoperative phone calls: is there another way?

Orientation, competencies, skills fairs: sorting it all out.