Estimating burn depth from thermal measurements

A new thermal perfusion probe operates by imposing a thermal event on the tissue surface and directly measuring the temperature and heat flux response of the tissue with a small sensor. The thermal event is created by convectively cooling the surface with a small group of impinging jets using room temperature air. The hypothesis of this research is that this sensor can be used to provide practical burn characterization of depth and severity by determining the thickness of non-perfused tissue. The measurement system was tested with a phantom tissue that simulates the blood perfusion of tissue. Different thicknesses of plastic were used at the surface to mimic layers of dead tissue. The sensor uses a parameter estimation procedure with analytical solutions of the Pennes bio-heat equation to determine effective values of blood perfusion, core temperature, and thermal contact resistance. Twelve different thicknesses of plastic were used along with three different flow rates of perfusate to simulate burned skin in the phantom perfusion system. The resulting values of thermal contact resistance for the complete set of measurements correlate well with the layer thickness. The values are also nearly independent of the flow rate of the perfusate, which shows that the parameter estimation can successfully separate these parameters. These results with simulated burns show the value of this minimally invasive technique to predict the burn depth in tissue.