Comparison of Aural and Rectal Temperature in Dogs Presenting to an Emergency Room

PURPOSE: To compare rectal and aural temperatures in canines presenting to a small animal emergency room. PATIENTS AND METHODS: We performed a prospective cohort study conducted between June 2022 and October 2022. One hundred and fifty-two dogs were evaluated that were presented to a private practice emergency room. Temperatures were obtained on presentation using both an aural Braun ExacTemp and a rectal Vet-Temp Rapid Digital Thermometer. The order of temperature measurement was randomized and recorded. Dogs were classified into three groups based on recorded temperature; normothermic (n = 105), hypothermic (n = 24), and hyperthermic (n = 23). Additional recorded parameters included: patient signalment, heart rate, respiratory rate, presence or absence of aural debris, coat length (classified as short, medium or long), body weight, body condition score, pain score, as well as venous lactate and non-invasive blood pressure, if performed. RESULTS: The overall aural temperatures were significantly lower than rectal temperatures. The average rectal and aural temperatures were 38.7°C (range 36.6–40.7°C) and 38.3°C (range 35.7°C–40.4°C), respectively. Among all canines, there was a moderate, statistically significant relationship between rectal and aural temperatures (r = 0.636; p < 0.001) and this relationship remained significant with a weaker relationship for normothermic dogs (r = 0.411; p < 0.001). For hyperthermic and hypothermic dogs, there was not a statistically significant relationship between rectal and aural temperatures. Hyperthermic dogs had a significantly higher respiratory rate than other groups and hypothermic dogs were more likely to have a short haircoat. Lastly, ambient temperature, but not humidity, influenced patient temperature. CONCLUSION: Our study found aural temperatures were consistently lower than rectal temperatures in dogs with both normal and abnormal rectal temperatures. Aural thermometry may not be an acceptable method of temperature measurement in the emergency patient cohort.