Relationship between pain and tissue damage due to thermal radiation

Abstract

Sites on the volar surfaces of the forearms of human subjects were blackened with India ink and exposed to thermal irradiances of from 50 to 400 mcal/cm2 sec. The exposure time and skin temperature at which threshold pain occurred, and which produced minimal blistering within 24 hours, were noted. The thermal inertia (k⍴c) of the skin was shown to vary directly with the level of irradiance. The receptors effective in mediating the pain sensation were calculated to be at a depth of approximately 200 μ and to have a threshold of approximately 43.2℃. Tissue damage rates with respect to temperature were derived empirically so that damage integrated over the time for which skin temperature was elevated over the pain threshold was equated to unity. The substitution of the ratio of these rates with respect to temperature for the stimulus ratio, in the prediction of the observed discriminable steps in pain sensation intensity, yielded faithful reproduction of the just noticeable differences observed for pain through the range of this sensation. Submitted on September 17, 1958

Thermal dose requirement for tissue effect: experimental and clinical findings

“…A hot water applicator was used to create 2° and 3° burns in human and pig skin, over wide range of temperatures (44-70°C). In a subsequent paper, Stoll and Greene obtained very similar results using more precise thermometry, but over a more narrow temperature range (6). An important point from the Stoll/Green data, is that the threshold for pain is much lower than the threshold for grossly detectable physical injury.…”

“…Thus for short heating times, the average temperature of the skin surface would have been much lower than the final target temperature, which is the temperature reported for the papers by Moritz and Stoll. Thus, heat up time and temperature difference at depth was not considered in the work of Moritz et al (5) or Stoll and Greene (6). For temperatures > 50°C, heat up time could have been a large proportion of the total thermal exposure time to achieve a thermal injury.…”

Mathematical Model of Skin Exposed to Thermal Radiation

“…It was desired, therefore, to devise a procedure for the prediction of injury from a knowledge of the heating intensity and time alone which could be used for estimating first the effects of square-wave pulses and, finally, the effects of variable pulses of known patterns. The problem is complicated not only by the need for considering damage during cooling but also by the fact that the thermal conductiity changes with temperature and vasomotion in the skin itself (2,4). For this reason the mathematical model developed in the present study was designed to provide for changes in the conductivity which would reflect the temperature-time heating patterns observed in the blackened skin of the earlier studies.…”

“…temperature history all other terms are known or can be assumed reliably and a simplification may be made in order to provide for solutions for k. Since The method of measuring and obtaining the experimental time-temperature histories used in this analysis has been described (2). In the present analysis, the measured surface temperatures (x = 0) were used as raw data and from each time-temperature point the value of thermal conductivity (k) of the skin at the surface was computed.…”

Parameter Estimation for a Biological System : Model and Experimentations

“…− Third-degree burns are also known as full thickness burns since the entire epidermis layer and the entire (or nearly all) dermis layer are destroyed. Henriques was a pioneer in the area of thermal injury and proposed that the amount of skin damage could be locally predicted on the basis of an Arrhenius-type function: (Henriques, 1947) (Fugitt, 1955) (Stoll et al, 1959) (Wu, 1982). Nevertheless, corresponding to the same time-space dependent temperature distribution, distinct injury degrees are predicted by these models.…”