Evaluation of the Temple Touch Pro, a Novel Noninvasive Core-Temperature Monitoring System

BACKGROUND: The Temple Touch Pro (TTP) is a novel system that estimates core temperature from skin over the temporal artery. We tested the hypothesis that this noninvasive system estimates core temperature to an accuracy within 0.5 degrees C. METHODS: Core temperature was continuously monitored in 50 adult and pediatric surgical patients by positioning the sensor patch of a TTP over one temporal artery. The sensor consists of a thermistor array near the skin surface, another set of thermistors above an insulator, and a second insulator between the upper unit and the environment. The sensor measures skin temperature and heat flux, from which the monitor unit estimates core temperature from a proprietary algorithm. Reference core temperature was measured from the esophagus or nasopharynx. We conducted agreement analysis between the TTP and the reference core temperature measurements using the 95% Bland-Altman limits of agreement for repeated measurement data. The proportion of all differences that were within 0.5 degrees C and repeat measures concordance correlation coefficient (CCC) were estimated as well. RESULTS: TTP and the reference core temperature measurements agreed well in both adults and pediatric patients. Bland-Altman plots showed no evidence of systematic bias or variability over the temperature from 35.2 degrees C to 37.8 degrees C. The estimated 95% lower and upper limits of agreement were -0.57 degrees C (95% confidence interval [CI], -0.76 to -0.41) and 0.57 degrees C (95% CI, 0.44 to 0.71), indicating good agreement between the 2 methods. Ninety-four percentage (95% CI, 87% to 99%) of the TTP temperatures were within 0.5 degrees C of the reference temperature. Good agreement was also supported by an estimated repeated measures CCC of 0.82 (95% CI, 0.66 to 0.91). The TTP core temperature measurements also agreed well with nasopharyngeal reference temperatures. CONCLUSIONS: The noninvasive TTP system is sufficiently accurate and reliable for routine intraoperative core temperature monitoring.