INFRARED THERMOMETRY IN THE DIAGNOSIS AND TREATMENT OF HEAT EXHAUSTION

Infrared (IR) thermometers (FirstTemp 2000A, Intelligent Medical Syste ms, California) were used to monitor tympanic temperature (T-ty) in 12 collapsed fun-runners suspected of suffering exertion-induced heat ex haustion (EIHE). Rectal temperature (T-re) was monitored via digital c linical thermometers. Conditions during the fun-run and in the field t reatment centre were cool (air temperature 16-18 degrees C, relative h umidity 60-65%). On admission, T-ty was (mean +/- SEM) 1.2 +/- 0.3 deg rees C lower than T-re. For admission plus subsequent monitoring data pooled, although T-ty correlated significantly with T-re (r = 0.86, p < 0.001), mean T-ty (37.4 +/- 0.2 degrees C) was significantly lower ( p < 0.01) than mean T-re (38.4 +/- 0.4 degrees C). Cotton wool ear pad s, applied to 10 of the runners on admission to minimise environmental effects on T-ty, did not significantly improve the IR monitoring. A T -ty greater than or equal to 37.1 degrees C predicted a T-re greater t han or equal to 38 degrees C (an established diagnostic criterion for EIHE) with a sensitivity of 0.93 and a specificity of 0.63. These data indicate that IR tympanic thermometry, when utilised in cool environm ents, can result in misdiagnosis of heat exhaustion. Although IR therm ometry shows some promise as a rapid, non-invasive means of monitoring core temperature, it should not be used in the diagnosis and treatmen t of heat exhaustion unless further research validates the method.