Infrared cameras overestimate skin temperature during rewarming from cold exposure. (July 2020)

• Record Type: Journal Article
• Authors: Maley, Matthew J.; Hunt, Andrew P.; Bach, Aaron JE.; Eglin, Clare M.; Costello, Joseph T.
• Is Part Of: Journal of thermal biology. Volume 91(2020)
• Publication Date: 2020-07
• Subjects: Infrared thermography -- Temperature measurement -- Thermoregulation -- Cold exposure -- Instrument validity; Thermobiology -- Periodicals; Temperature -- Periodicals; Biology -- Periodicals; Thermobiologie -- Périodiques; Thermobiology; Periodicals; 571.46
• DOI: 10.1016/j.jtherbio.2020.102614
• Languages: English
• ISSNs: 0306-4565

Abstract

Abstract: Objective: The primary aim of this study was to assess the accuracy of an infrared camera and that of a skin thermistor, both commercially available. The study aimed to assess the agreement over a wide range of skin temperatures following cold exposure. Methods: Fifty-two males placed their right hand in a thin plastic bag and immersed it in 8 °C water for 30 min whilst seated in an air temperature of 30 °C. Following hand immersion, participants removed the bag and rested their hand at heart level for 10 min. Index finger skin temperature (Tsk ) was measured with a thermistor, affixed to the finger pad, and an infrared camera measured 1 cm distally to the thermistor. Agreement between the infrared camera and thermistor was assessed by mean difference (infrared camera minus thermistor) and 95% limits of agreement analysis, accounting for the repeated measures over time. The clinically significant threshold for Tsk differences was set at ±0.5 °C and limits of agreement ±1 °C. Results: As an average across all time points, the infrared camera recorded Tsk 1.80 (SD 1.16) °C warmer than the thermistor, with 95% limits of agreement ranging from −0.46 °C to 4.07 °C. Conclusion: Collectively, the results show the infrared camera overestimated Tsk at every time point following local cooling. Further, measurement of finger Tsk from the infrared camera consistently fell outside the acceptable level of agreement (i.e. mean difference exceeding ±0.5 °C). Considering these results, infrared cameras may overestimate peripheral Tsk following cold exposure and clinicians and practitioners should, therefore, adjust their risk/withdrawal criteria accordingly. Highlights: Infrared cameras overestimate skin temperature during rewarming after cold exposure. The acceptable level of agreement was not met at any time point during rewarming. Infrared cameras are not recommended to accurately measure cold skin temperatures.