ASSESSMENT OF TISSUE VIABILITY BY THERMOGRAPHY AFTER EXPERIMENTALLY PRODUCED FROSTBITE OF THE RABBIT EAR

Since it is difficult and time-consuming to monitor the formation of a demarcation line in frostbite by visual inspection only, thermography was used to study experimental freezing injuries of the rabbit ear. I n 8 rabbits, anesthetized with ketamine hydrochloride and xylazine hyd rochloride. frostbite was induced by pressing the bottom of a glass bo ttle 2 cm in diameter, filled with liquid nitrogen against the shaved ear skin. Thermography was performed on both ears after 2, 24, and 48 hours, and one and 3 weeks. At 2 to 48 hours the frostbitten area was clearly warmer than the surroundings, after one week there were ill-de fined diffuse cold spots in the injured area, and after 3 weeks a cold area had become clearly demarcated with a warm zone between the cold area and the surroundings. Thermography is an easy, noninvasive method for monitoring thermal changes after experimental frostbite, but its clinical value is as yet unresolved.