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

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°C.

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°C and repeat measures concordance correlation coefficient (CCC) were estimated as well.

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°C to 37.8°C. The estimated 95% lower and upper limits of agreement were -0.57°C (95% confidence interval [CI], -0.76 to -0.41) and 0.57°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°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.

The noninvasive TTP system is sufficiently accurate and reliable for routine intraoperative core temperature monitoring.