Infrared thermographic analysis of surface temperature of the hands during exposure to normobaric hypoxia

Jones, Daniel, Samuel F. Covins, Gavin E. Miller, Kenneth I. Morrison, Alexander G. Clark, Samuel D. Calcott, Alasdair M. Anderson, Samuel J.E. Lucas, Christopher H.E. Imray, and the Warwick Altitude Research Group. Infrared red thermographic analysis of surface temperature of the hands during exposure to normobaric hypoxia. High Alt Med Biol. 00:000-000, 2018.-Frostbite and other cold-related injuries commonly develop during prolonged exposure to the low environmental temperatures of polar and mountainous regions. Hypoxia is a potent sympathetic stimulus that causes vasoconstriction of the peripheral blood vessels, which may further compound the risk of developing a cold-related injury during high-altitude exposure. To investigate this, we utilized portable infrared thermographic technology to quantitatively measure changes in the surface temperature of the hands during exposure to increasing levels of normobaric hypoxia in a temperature-controlled high-altitude simulation. Surface temperature was assessed at four anatomical locations on both the left and right hands in a cohort of 10 healthy male participants at a series of predetermined levels of hypoxia (0.20 fraction of inspired oxygen [F_IO₂] [pre- and postexposure], 0.172 F_IO₂, 0.145 F_IO₂, 0.128 F_IO₂). Thermographic analysis revealed an overall decrease in peripheral temperature across the anatomical regions of the hands as the hypoxic stimulus increased, with statistically significant reductions observed at all four anatomical sites during exposure to 0.128 F_IO₂ (p < 0.05). These findings demonstrate that portable infrared thermography can be used to detect reductions in peripheral surface body temperature during exposure to normobaric hypoxia.