Elsevier

The Lancet

Volume 360, Issue 9333, 24 August 2002, Pages 603-609
The Lancet

Articles
Infrared ear thermometry compared with rectal thermometry in children: a systematic review

https://doi.org/10.1016/S0140-6736(02)09783-0Get rights and content

Summary

Background

Infrared ear thermometry is frequently used in children, because this is a quick method of taking temperature and the ear is easily accessible. Our aim was to evaluate agreement between temperature measured at the rectum and ear in children.

Methods

We did a systematic review of studies comparing temperature measured at the rectum (the reference site) using mercury, electronic, or indwelling probe thermometers, with temperature measured at the ear (the test site) using infrared ear thermometers. Heterogeneity between studies was investigated by exploring subgroups according to the mode of the infrared ear thermometer.

Findings

44 studies containing 58 comparisons (5935 children) were eligible for inclusion in this review. Outcome data were available in reports from 12 comparisons (2312 [39%] children), and data on individual patients were obtained for a further 19 comparisons (2129 [36%] children). 31 comparisons (4441 [75%] children) were therefore included in the meta-analysis. The pooled mean temperature difference (rectal minus ear) was 0·29°C (95% limits of agreement −0·74 to 1·32). We pooled data by ear device mode and the mean temperature differences were rectal mode 0·15°C (−0·95 to 1·25), actual 0·70°C (−0·20 to 1·60), core 0·25°C (−0·78 to 1·27), oral 0·34°C (−0·86 to 1·54), tympanic 0·62°C (−0·40 to 1·64) and mode not stated 0·32°C (−0·57 to 1·21). There was significant residual heterogeneity in both mean differences and sample SDs within the groups of ear device mode.

Interpretation

Although the mean differences between rectal and ear temperature measurements were small, the wide limits of agreement mean that ear temperature is not a good approximation of rectal temperature, even when the ear thermometer is used in rectal mode. Our finding suggests that infrared ear thermometry does not show sufficient agreement with an established method of temperature measurement to be used in situations where body temperature needs to be measured with precision.

Introduction

Accurate temperature measurement is important, especially in neonates1 and immune-compromised children2 in whom suspicion of infection could result in investigations, administration of antibiotics, and even hospital admission. Temperature measurement can be difficult in children, particularly when they are uncooperative or restless. Infrared thermometers that enable temperature to be measured at the external ear canal have become available in the past 15 years, and have been introduced into widespread clinical use.3, 4, 5 Because the ear is easily accessible and the procedure is very quick, this method is acceptable for use in children. The infrared detector senses electromagnetic radiation emissions from tissue within view of the probe. A microprocessor calculates the temperature value of the observed structures. Depending on the mode selected, a numerical constant, known as an offset, is added to the measured temperature to generate estimated core, tympanic, oral, or rectal temperatures with which clinicians may be more familiar.31

In another systematic review,32 we showed that agreement between temperature measured at the axilla and rectum in children was low. This poor concurrence has implications for clinical management when temperature needs to be measured accurately. Infrared ear thermometry is now commonly used in children, both in hospital and in the community. In the USA, 64% of paediatricians and 65% of family practice physicians use this method.3 In this systematic review, we investigate the agreement between temperature measured at the ear and at the rectum in children.

Section snippets

Study identification

A single reviewer (JVC) used a comprehensive strategy to search Medline (1966 to January, 2000), CINAHL (1982 to December, 1999), British Nursing Index (to June 1999), the Cochrane Library (2000 Disk Issue 1), the ASLIB Index to theses Great Britain and Ireland (1970–99), the National Research Register (2000 Disk Issue 2), and Bath Information and Data Services Index to Scientific and Technological Proceedings (1982–2000). Authors and suppliers of clinical thermometers were asked for details of

Description of studies

Our preliminary search identified 101 studies. There was initial agreement between the two reviewers on study eligibility in all but six studies, and on methodological quality in all but nine. 44 studies (39 in English) that described 56 comparisons were eligible for the review. One additional eligible unpublished study and one eligible unpublished comparison were identified (personal communications with authors of two studies: K R Powell23 and R J Yetman16). The studies included 5935 children.

Discussion

Temperature measured at the ear has obvious advantages over temperature measured at the rectum, such that if the two methods agree sufficiently well, then the ear-based method could replace the rectal method. In this study we noted small mean differences, but wide limits of agreement, between the two temperature sites. The pooled mean difference was smallest when the ear device was used in the rectal mode, but the limits of agreement remained wide. For example, if temperature measured at the

Search strategy

Set numberTerm searched or sets combined
1PAEDIATRIC in TI,AB,MESH
2PEDIATRIC in TI,AB,MESH
3explode “Pediatrics”/ all subheadings
4p*ediatric*
5child*
6infant*
7baby or babies
8neonat*
9newborn*
10toddler*
111 or 2 or 3 or 4 or 5 or 6 or 7 or 8 or 9 or 10
12THERMOMETER in TI,AB,MESH
13explode “Thermometers”/ all subheadings
14thermometer*
15TEMPERATURE in TI,AB,MESH
16temperature
1712 or 13 or 14 or 15 or 16
18ear*
19aural
20EAR in TI,AB,MESH
21explode “Ear-External”/ all subheadings
22explode

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