Evaluation of Infrared Tympanic Thermometers on Mild Hypothermic Subjects and in Cold Environments.
DEFENCE AND CIVIL INST OF ENVIRONMENTAL MEDICINE DOWNSVIEW (ONTARIO)
Pagination or Media Count:
The objective of the present study was to evaluate infrared tympanic thermometers ITTs on hypothermic subjects and under operationally relevant ambient conditions. Eight subjects 2 of them female were cooled in 8-10 deg C water for 25 min on three occasions. Tympanic temperatures obtained with three brands of ITTs Genius, Thermoscan, and Diatek were compared to three other core temperature estimates esophageal, rectal, and ear canal during the cold water immersions, and in a second series of experiments, to a temperature controlled target in cold air environments. On average, tympanic temperature Tty measured from the three ITT instruments was 0.99 plus or minus 0.18 deg C lower than the other core estimates. The differences between Tty and each of the three core estimates were not different, but the three differences were larger for the Genius ITT 1.49 plus or minus 0.36 deg C compared to the two other instruments 0.63 plus or minus 0.21 deg C for Diatek 0.63 plus or minus 0.20 deg C for Thermoscan. Furthermore, the ITT instruments failed to perform adequatly in the cold. It was concluded that tympanic temperature measured by ITT instruments underestimates core temperature during hypothermia in humans, and the ITTs can not be used below their specified operating temperature.
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