Continuous measurement of tympanic temperature with a new infrared method using an optical fiber

The purpose ofthis study was to investigate the utility of an infrared tympanicthermometry by using an optical fiber for measuring tympanictemperature (T_ty). In the headcooling and facial fanning tests during normothermia, rightT_ty measured by this method(infrared-T_ty) and esophagealtemperature (T_es) were notaffected by decreased temple and forehead skin temperatures, suggestingthat the infrared sensor in this system measured the infrared radiationfrom the tympanic membrane selectively. Eight male subjects took partin passive-heat-stress and progressive-exercise tests. No significantdifferences among infrared-T_ty,the left T_ty measured bythermistor (contact-T_ty), andT_es were observed at rest or atthe end of each experiment, and there was no significant difference inthe increase in these core temperatures from rest to theend. Furthermore, there were no significant differences inthe core temperature threshold at the onset of sweating and slope (therelationship of sweating rate vs.infrared-T_ty and vs.contact-T_ty). Theseresults suggest that this method makes it possible to measureT_ty accurately, continuously, andmore safely.