The effect of ambient temperature extremes on tympanic and oral temperatures

Exposure to ambient temperature extremes immediately preceding emergency department triage may affect tympanic membrane temperatures taken with infrared emission detection thermometers. In a prospective, unblinded study, 20 healthy subjects, on 2 separate days, underwent 15-minute exposures to hot (43.5 degrees C) and cold (-5 degrees C) temperature extremes in an environmental control room (ECR). Tympanic and oral temperatures were taken at baseline and at 2-minute intervals for 20 minutes after exiting the ECR. Rectal temperatures remained stable during the exposures. Oral temperatures rose significantly after hot exposure (P less than .05; max 0.4 degrees C) and briefly decreased after cold exposure (max 0.5 degrees C). Tympanic temperatures were elevated for 20 minutes after hot exposure (max 0.8 degrees C) and decreased briefly only in male subjects after cold exposure (max 0.7 degrees C). Individuals demonstrated wide variability in their temperature responses. Tympanic and oral temperatures taken within the first 20 minutes after exposure to outdoor temperature extremes may fail to accurately reflect the patient's true temperature.