NICE and warm

Abstract

Editor—We read with interest the editorial by Harper and colleagues1Harper CM Andrzejowski JC Alexander R NICE and warm.Br J Anaesth. 2008; 101: 293-295Abstract Full Text Full Text PDF PubMed Scopus (39) Google Scholar regarding the recent National Institute of Clinical Excellence (NICE) guidelines on inadvertent perioperative hypothermia.2NICE Perioperative hypothermia (inadvertent): the management of inadvertent perioperative hypothermia in adults.in: NICE Clinical Guideline 65. National Institute for Health and Clinical Excellence, London2008Google Scholar We had been prompted by these guidelines to conduct an audit into current practice at our District General Hospital. A retrospective case note analysis of 57 adult patients revealed poor compliance with the majority of the recommendations. For example, 33% of our patients had a preoperative tympanic temperature of below 36.0°C, a distribution that has already been noted in a surgical population.3Mitchell AM Kennedy RR Preoperative core temperatures in elective surgical patients show an unexpected skewed distribution.Can J Anaesth. 2001; 48: 850-853Crossref PubMed Scopus (18) Google Scholar A systematic literature review in 2002 found a range of tympanic temperature of 35.4–37.8°C.4Sund-Levander M Forsberg C Wahren LK Normal oral, rectal, tympanic and axillary body temperature in adult men and women: a systematic literature review.Scand J Caring Sci. 2002; 16: 122-128Crossref PubMed Scopus (355) Google Scholar Is the NICE trigger of 36°C appropriate? Many of our patients are admitted on the day of surgery and data were collected during a relatively warm week in March. We found a postoperative hypothermia rate of 40%, which is double that quoted by Harper and colleagues,1Harper CM Andrzejowski JC Alexander R NICE and warm.Br J Anaesth. 2008; 101: 293-295Abstract Full Text Full Text PDF PubMed Scopus (39) Google Scholar but given the 33% preoperative hypothermia rate, is this so bad? Intraoperative warming is indicated for surgery of duration >30 min, that is, in 39 (68%) patients in our audit, but warming was given only in 15 (38%) of those cases. Notably, temperature monitoring was only used in three (8%) of these patients and was of a recommended frequency in only one case. We expected that the performance in the more protocol-based domain of the post-anaesthetic care room (PACU) would be better. However, while nearly all patients (91%) had their temperature measured on admission, the treatment or documentation of hypothermia was minimal. No patient had regular temperature measurement, for 30 (53%) patients no temperature was documented upon return to the ward and five (19%) of those with a documented temperature were hypothermic. We agree with Harper and colleagues these shortcomings will result in additional costs: that of forced-air warmers, disposables, additional thermometers, and longer stays for patients in the PACU. Given the influence of previous NICE guidelines in the purchasing of ultrasound machines and our current shortcomings, we hope to improve care for our patients. Once the audit tool is available, it would be interesting to compare our results with other units in the UK. Editor—We thank Drs Williams and Harrison for their interest in our article.1Harper CM Andrzejowski JC Alexander R NICE and warm.Br J Anaesth. 2008; 101: 293-295Abstract Full Text Full Text PDF PubMed Scopus (39) Google Scholar As we mentioned, all methods of temperature measurement have significant problems, as the degree of accuracy seems to increase only with their degree of invasiveness. Tympanic temperatures are a particular problem in clinical practice. One of the author's (C.M.H.) institutions swapped over from temporal artery thermometers to tympanic and found a sudden increase in the incidence of postoperative hypothermia. We then audited the incidence of postoperative hypothermia according to each form of measurement and found that the tympanic thermometer read on average 0.73°C lower than the temporal artery, giving incidences of 9.1% for temporal and 60.3% for tympanic. The temporal artery thermometer has been shown to be reasonably accurate in the clinical situation and has even been used to demonstrate improved outcomes in warmer patients. In fact, this study suggests that outcomes are improved if patients’ temperatures are kept above 36.5°C (reference 16 in the original article). C. M. Harper* Brighton, UK *E-mail: [email protected]