Studies of Thermal Injury: II. The Relative Importance of Time and Surface Temperature in the Causation of Cutaneous Burns.

A. R. Moxr, M.D., and F. C. HENRIQuES, JR., Ph.D. (From the Departmen of Legal Medcixe, Harvrd Medical School, Boston, Mass.) Although it is common knowledge that there is an inverse relationship between the intensity of a thermal exposure and the amount of time required to produce a burn, there is remarkably little available information as to the rate at which burning of huiman skin occurs at any given surface temperature or as to the pathogenesis and pathological characteristics of burns in which the duration and degree of rise in intracutaneous temperature was known or could be calculated with any degree of accuracy. Considerable information regarding the time-temperature thresholds at which cutaneous burning occurs in animals is provided by the experiments of Hudack and McMaster1 and of Leach, Peters, and Rossiter.2 In the former, water at temperatures ranging between 420 and 670C. either was applied directly or was passed through a thinwalled glass chamber, the base of which was brought in contact with the skin of mice. In the experiments performed by Leach, Peters, and Rossiter water was pumped through a metal chamber at temperatures ranging between 450 and 8o0C. and the base of the chamber was held in contact with the skin of guinvea-pigs for varying periods of time. Both groups of investigators observed that the time required to produce injury diminished rapidly as the temperature of the water was raised. The former reported that a source temperature of 440C. was critical for the causation of hyperthermic edema. The latter reported that the critical temperature for causing permanent and irreversible injury of guinea-pig skin lies between 500 and SS°C. Neither of the above-cited investigations provided data from which the timetemperature requirements for the production of burns of huiman skin could be estimated. Although Leach, Peters, and Rossiter 2 made a careful study of the pathological characteristics of different kinds of burns of guinea-pig skin, the extent to which these chges are representative of those that occur in cutaneous burning in man was not disclosed.