Quantifying the role of burn temperature, burn duration and skin thickness in an in vivo animal skin model of heat conduction

To determine the extent to which heat conduction through skin is affected by skin thickness, burn temperature, and burn duration, we perform a suite of experiments using an in vivo porcine (pig) model. Fourteen different burn conditions are considered, and each burn condition is replicated at least four times, giving a total of sixty four individual experimental burns. The subdermal temperature within the skin is recorded as a function of time during each experiment. To quantitatively interpret the experimental data, we develop an exact solution of a simplified, depth-averaged, heat equation. Calibrating this solution to the experimental data provide estimates of the effective thermal diffusivity of the skin, α, and the effective thermal loss rate, k. Estimates of α and k are obtained for the fourteen different, clinically relevant, burn conditions. Overall, we find α = 0.03 ± 0.02 mm2/s (to one significant figure), and is approximately independent of the burn duration, burn temperature, and skin thickness (H). This estimate implies that the time required for thermal energy to diffuse vertically down, through the skin of thicker (H = 2.27 mm) and thinner (H = 1.40 mm) skinned animals is approximately 170 and 70 s, respectively. We find that k = 0.002 ± 0.002/s (to one significant figure). In summary, our results provide contemporary estimates for the thermal properties of in vivo porcine skin, which has broad application to heat transfer modelling investigations of thermal injury prevention and thermal therapy studies.