Evaluation of thermometers for ear temperature measurement at the wards in a university hospital

Dissertação para obtenção do Grau de Mestre em Engenharia Biomédica

Since mercury thermometers were banned due to environmental concerns, hospitals started to use electronic thermometers for measuring body temperature. Body temperature can be measured from different body parts, although the least invasive and quickest is preferred and therefore eardrum measurements are frequently taken. However, lately the staff feels that the taken measurements are not accurate. A new purchasing agreement for the purchase of these devices renders a good opportunity to study further the use of these devices at the wards of the university hospital, study their maintenance process, identify what performance is essential for the clinical usage, the parameters that are essential to measure and also identify ear thermometers in the market that can be used for comparative study. Temperature measurements were taken with the help of an infrared ear thermometer, Covidien Genius2, in its calibration blackbody device at the R&D department of the Huddinge Hospital in order to verify accuracy claims. This data were compared against other studies and measurements of other infrared ear thermometers devices, the Braun ThermoScan Pro 4000 and also a digital contact thermometer, Welch Allyn Suretemp Plus, applied to different body sites. Informal meetings also took place in order to get more information about the devices and to know where they were used and repaired. It was found that Genius2 measured temperature accurately when compared with a blackbody radiator. Regarding the Braun, it showed an accurate estimate of core temperature in comparison to invasive pulmonary artery catheter thermometry. Electronic tympanic thermometers proved to be a good replacement for conventional methods of thermometry. However, preventive maintenance should occur more often, since the devices are very fragile. Tympanic thermometers are generally very accurate instruments. Most likely, problems are not related to the thermometers themselves, they are possibly the result of an inadequate understanding of the limitations of ear thermometry.