Performance testing of an innovative telemetric temperature sensor in animals

Abstract: This study consists of a first assessment of a new technological solution (e-Celsius™ prototype) designed to perform intra peritoneal (IP) temperature measurements in animals. The tested prototype temperature sensor is composed of a miniaturized electronic sensor (capsule), which uses wireless technology to transmit temperature data to a dedicated monitor. The performance assessment was based on the comparison with commercially available analog tools (VitalSense, Jonah™ ingestible core temperature capsules) considered as gold standards. The variability (mean absolute deviation) of the calculated difference score around its mean value was taken as a reliability index. Thus, 6 pairs of capsules (1 Jonah™+1 e-Celsius™ prototype temperature sensor) were constituted. All the electronic capsules were first tested in a water bath heated to 37 °C and then implanted intra-abdominally in 6 male Sprague Dawley rats. The capsules' performances were assessed while rats were in free living conditions (24 h alone in cage) and then again during the cooling process (anesthesia+ice). In a second step, a test was designed to assess the maximum distance of communication between sensors and the monitor. The mean absolute deviation of the difference scores was greater in the 24 h free living conditions (±0.17 °C) compared to the water bath conditions (±0.04 °C). No difference was observed when compared to the cooling stage (±0.1 °C). Considering that 50% of the data collected as a satisfactory performance criterion, the Jonah™ device could not be used at a distance exceeding 0.5 m while the maximum distance recorded for the e-Celsius™ was 3 m. The minimum life span for the tested e-Celsius™ and Jonah™ capsules was 14 days. The development of a precise calibration method is needed to finalize its validation.