Revista de Gravidez e Saúde Infantil

Abstrato

Metrological Assessment of Infrared Tympanic Thermometers: A Safety Measure

Ana Luisa Silva, Cláudia Pereira, Sílvia Moutinho, Cecilia Rodrigues, Humberto S Machado and Idalina Beirao

Background: There are different temperature readings in different body sites that are estimated values of the core temperature. The IR tympanic thermometers measure the thermal radiation of the tympanic membrane. These devices are often considered the best non-invasive and most accurate technique to measure body temperature. The incorrect use and the features of the IR tympanic thermometers may lead to significant errors in temperature readings. A metrological approach allows the analysis of the accuracy of the IR tympanic thermometers when compared to a standard electronic device. The main purpose of this study was to assess the measuring errors of the infrared (IR) tympanic thermometers over time and to decide the best time interval between metrological assessments. Methods: The metrological control of IR tympanic thermometers (n=125 used in adult and n=21 in paediatric patients) was based on the comparison with a thermal imaging black body device. An acceptance criterion (AC) of ±0.2°C was considered for metrological control. Results: 93.90% of the errors of low temperature readings (32°C) and 94.24% of the errors of high temperature readings (40°C) were within the acceptance criterion (±0,2°C). Results show 6% of the errors out of specifications. The maximum and minimum errors were +2.5°C and –0.8°C and +0.8°C and -5.2°C for low and high temperatures, respectively. For high temperatures the errors decrease gradually over time unlike to the observed regarding the low temperatures. Conclusions: The variability of errors might be device related; nevertheless it does not preclude its reliability. Significant errors were not found. The accuracy of the IR tympanic thermometers improved over time for high temperatures. Regular metrological assessments are needed to identify errors and assure a good performance of the IR tympanic thermometers.