Electronic ‘tympanic’ infrared thermometers have gained wide acceptance within the medical community. Although previous paediatric studies have shown a good correlation between rectal and ‘tympanic’ thermometers (Terndrup and Milewski 1991; Chamberlain et al. 1991), there are concerns being raised with respect to their reliability. Here we report data from a study into the relationship between the left and right ear canal temperatures in children between nine months and five years old inclusive.
Medical ethical approval was obtained, and temperatures were only taken bilaterally if the child’s parent or guardian gave their verbal consent. The temperature of the ear canal was taken using an infrared thermometer (Genius 5: TycoHealth, N Ireland) following a standardised hospital protocol. The choice of the side of the first ear to be assessed was alternated between consecutive patients. Basic demographic data were also recorded. The data was analysed using SPSS.
A good correlation was found between the left and right ear canal temperature recordings (n = 17; R2 = 0.7708). The average temperature was 36.9°C with a range from 36.0° to 37.7°C. Comparison of first and second recorded temperature irrespective of side also showed a reasonable correlation (R2 = 0.6502). However, it appeared that the first recorded temperature tended to be consistently lower than the second in this age group.
Even though this was a small normative study, this is the first report that has considered that some of the variability noticed in use of this assessment methodology might derive from a mixture of the technology and the physiology. It would appear that in young children, there is a reaction to the first reading that causes the second reading to be generally smaller. As such it would appear that reading from one ear only could lead to errors in the monitoring of temperature in this vulnerable group.