Can we trust the new generation of infrared tympanic thermometers in clinical practice?

Aims and objectives: To explore the reliability and validity of the new generation of infrared tympanic thermometers, comparing with rectal and core temperature, and to decide their applicability to clinical practice.

Background: Digital contact thermometers for rectal measurements and infrared tympanic thermometers are the most common way to measure patients' temperature. Previous studies of the infrared tympanic thermometers revealed misdiagnosis, and validity of early models was questioned.

Design: Reliability and validity study.

Methods: Temperature was measured with two infrared tympanic thermometers brands in both ears and compared with rectal temperature twice a day at the ward (n = 200). At the intensive care unit, patients (n = 42) underwent the same measurement procedures every fourth hour for 24 hours. In addition, core temperature was measured. Statistical analyses included descriptive and mixed models analyses.

Results: Ward: Infrared tympanic thermometers measured the temperature lower than the rectal temperature. Descriptive statistics indicate higher variation in temperature measurements made in the ear. No statistically significant difference in temperature was found for left ear vs. right ear. Intensive care unit: The mean rectal temperature was higher than the mean core and ear temperature. Mixed models analyses of the temperatures at the ward and the intensive care unit showed the same overall trends, but with less discrepancy between the two infrared tympanic thermometers brands, compared with the rectal temperature. Only rectal temperature measurements differed significantly from the core temperature.

Conclusion: Our study shows good reliability using the new generation of infrared tympanic thermometers. We found good agreement between core and infrared tympanic thermometers at the intensive care unit, but the measuring inaccuracy for infrared tympanic thermometers was greater than expected.

Relevance to clinical practice: The new generation of infrared tympanic thermometers may be used in clinical practice, but it is important to do repeatedly measurements if there is discrepancy between the temperature and the observation of the patient condition.