Steam sterilization processes affect the stability of clinical thermometers: Thermistor and prototypal FBG probe comparison

Temperature is one of the most frequently measured physical quantities in clinical environment and a good biomarker of illness. The need for reusable probes, which have to be sterilized to prevent infections, requires the metrological qualification of thermometer probes in response to ageing effects induced by several sterilization processes. In this study, we investigated the effect of repeated sterilizations on both a commonly-used autoclavable thermistor probe and a prototypal Fiber Bragg Gratings (FBG) probe for temperature measurements. Findings highlighted a greater reliability of the proposed FBG probe than the commercial thermistor. Specifically, the FBG probe was able to withstand repeated sterilization cycles while maintaining stability in the measurement accuracy. Moreover, the proposed configuration for the FBG probe was immune to unwanted mechanical strain by providing a dynamic response fit for the measurement of temperature.