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Updated: May 23, 2026
Fabrication and Testing of Photonic Thermometers
Published on: October 24, 2018
Homemade thermometry instruments in the field
Mathieu Pasquier1, Valentin Rousson, Grégoire Zen Ruffinen
1Emergency Service, University Hospital Center, Lausanne, Switzerland. mathieu.pasquier@chuv.ch
Objective:
Esophageal temperature is the gold standard for in-the-field temperature monitoring in hypothermic victims with cardiac arrest. For practical reasons, some mountain rescue teams use homemade esophageal thermometers to measure esophageal temperature; these consist of nonmedical inside/outside temperature monitoring instruments that have been modified to allow for esophageal insertion. We planned a study to determine the accuracy of such thermometers.
Methods:
Two of the same model of digital cabled indoor/outdoor thermometer were modified and tested in comparison with a reference thermometer. The thermometers were tested in a water bath at different temperatures between 10°C and 35.2°C. Three hundred measurements were taken with each thermometer.
Results:
Our experimental study showed that both homemade thermometers provided a good correlation and a clinically acceptable agreement in comparison with the reference thermometer. Measurements were within 0.5°C in comparison with the reference thermometer 97.5% of the time.
Conclusions:
The homemade thermometers performed well in vitro, in comparison with a reference thermometer. However, because these devices in their original form are not designed for clinical use, their use should be restricted to situations when the use of a conventional esophageal thermometer is impossible.
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