Comparison of peripheral temperature measurements with core temperature

The authors' objective of this study was to identify a peripheral method of measuring body temperature that approximates core body temperature. A cross-sectional design was used to compare peripheral measures of body temperature with core temperature. Peripheral temperatures were measured in the ear using two infrared thermometers, in the mouth using a mercury in glass thermometer, electronic thermometer, and chemical indicator thermometer, in the axilla using a mercury in glass thermometer, electronic thermometer, and chemical indicator thermometer, and in the rectum using a mercury in glass thermometer and electronic thermometer. A statistically significant difference was found between peripheral temperature measures and core temperature, except for the axillary chemical indicator temperature and both aural temperatures. Pearson correlation coefficients of > or = 0.79 were found for the association of pulmonary artery temperatures with oral mercury, oral electronic, axillary electronic, rectal mercury, and rectal electronic temperatures. Correlation coefficients were less than 0.20 between pulmonary artery and aural temperatures measured by both devices. Based on results from this study, there is no perfect instrument for approximating core temperature, although the electronic thermometer used orally has a low mean difference (0.18 degree C), low standard deviation of the difference (0.24 degree C), and a correlation coefficient of 0.79.