Evaluation of a Wireless Ingestible Temperature Probe in Cardiac Surgery

OBJECTIVES: CorTemp™ is a wireless intestinal temperature monitoring system in the form of an ingestible pill and an external receiver. The aim of the study was to evaluate the system's accuracy and practicality during cardiac surgery. METHODS: A repeat measures design using simultaneous temperature readings from the pulmonary artery (T pa), a nasopharyngeal thermometer (T np), skin thermometers (T sk) and the CorTemp™ system (T in), was conducted in 15 patients undergoing elective cardiac surgery under hypothermic conditions. RESULTS: Only 67 % of patients' data was analysed and the statistical analysis of a total of 264 sets of readings showed a clinically significant temperature difference of T in compared to the other thermometers with limits of agreement between T in and T pa, T np and T sk (± 0.35 to ± 1.53 °C), (± 0.72 to ± 1.63 °C) (± 0.40 to ± 1.84 °C), respectively. The T in bias was significantly different from that of T pa ( P = 0.0023), T np ( P = 0.018) and T sk ( P = 0.0005) during rewarming. The T in rate of temperature change was also found to be significantly slower during the rewarming period. CONCLUSIONS: The significant temperature differences detected during rewarming urge caution regarding CorTemp™'s use as an accurate estimator of brain temperature in cardiac surgery. Further studies are required to assess its potentially useful role as a body core and intestinal temperature monitoring system and as a useful adjunct in investigating bowel ischaemia aetiology in cardiac surgery.