Core temperature measured in the auricular canal: comparison between four different tympanic thermometers.

Four different tympanic thermometers, absorbing infra-red radiation, (FirstTemp, Diatek, Ivac and Genius) were studied. Variations from repeated measurements and reliability of tympanic temperature compared to oesophageal, rectal and pulmonary artery temperature were studied. Core temperature measured by the "FirstTemp" and the "Genius" thermometers showed slightly higher values than core temperature measured by oesophageal, rectal and pulmonary artery thermistors. Compared to oesophageal temperature "FirstTemp" showed 0.56 degrees C and "Genius" 0.28 degrees C higher values, while the "Diatek" and the "Ivac" gave slightly lower values (-0.5 degrees C and -0.28 degrees C). All four thermometers were found accurate for repeated measurement both in terms of standard deviation and coefficient of variance. All four tympanic thermometers showed good accuracy for changes in core temperatures compared to the reference thermistors (r2 values 0.96 for "FirstTemp", 0.88 for "Diatek", 0.96 for "IVAC" and 0.95 for "Genius"). The tympanic thermometer was found to be a valuable alternative for measuring core temperature in most clinical settings.