Authors of a systematic review in this week's issue of THE LANCET suggest that measuring infants' body temperature in the ear is not a reliable means of assessing precise body temperature.
Infrared ear thermometry is frequently used in children--this is a quick method of taking temperature, and the ear is easily accessible. Rosalind Smyth and colleagues from the University of Liverpool, UK, evaluated the agreement between temperature measured at the rectum and ear in children.
31 comparisons (which included data for just under 4500 children) were assessed. Although the pooled mean temperature difference (rectal minus ear) was small (0.29ºC), there were some wide individual differences, suggesting that the use of ear thermometry could either overestimate or underestimate body temperature, with implications for clinical management.
Rosalind Smyth comments: "Our systematic review has shown that in children, the agreement of infrared ear thermometry with rectal temperature measurements is low, and that differences were in either direction. We used rectal temperature for the reference measure because it has shown good agreement with core body temperature and because it is an established method of measuring temperature in children. The low level of agreement between the two methods might be attributable to inaccuracies in measurement at either site. Heterogeneity between studies made comparisons difficult and could be attributable to inconsistencies in ear modes between different manufacturers. However, the implications of our findings are that measurements taken with infrared ear thermometry cannot be used as an approximation of rectal temperature, even when the device is used in rectal mode. This finding means that the presence of fever might not be detected, and accurate temperature might not be obtained in situations in which body temperature needs to be measured with precision."
In an accompanying Commentary (p 584), Segun Akinyinka from University College Hospital, Ibadan, Nigeria, concludes: "Although tympanic thermometry is acceptable to patients, parents, and healthcare practitioners, it is not yet clear that tympanic thermometry is sufficiently accurate to measure core temperature."
Contact: Suzanne Hughes, Communications Manager, The Royal Liverpool Children's NHS Trust - Alder Hey, Eaton Road, Liverpool L12 2AP, UK; T) +44 (0)151 252 5693; F) +44 (0) 151 252 5456; E) firstname.lastname@example.org
Dr Segun Akinyinka, Department of Paediatrics, College of Medicine, University College Hospital, Ibadan, Nigeria; T) +234 2 241 3503 x2420/2751; F) +234 2 241 0588; E) email@example.com