SENSITIVITY ANALYSIS OF ONE-DIMENSIONAL HEAT-TRANSFER IN TISSUE WITH TEMPERATURE-DEPENDENT PERFUSION

Design criteria for implantable, heat-generating devices such as the t otal artificial heart require the determination of safe thresholds for chronic heating. This involves in-vivo experiments in which tissue te mperature distributions are obtained in response to known heat sources . Prior to experimental studies, simulation using a mathematical model can help optimize the design of experiments. In this paper, a theoret ical analysis of heat transfer is presented that describes the dynamic , one-dimensional distribution of temperature from a heated surface. L oss of heat by perfusion is represented by temperature-independent and temperature-dependent terms that can reflect changes in local control of blood flow. Model simulations using physiologically appropriate pa rameter values indicate that the temperature elevation profile caused by a heated surface adjacent to tissue may extend several centimeters into the tissue. Furthermore, sensitivity analysis indicates the condi tions under which temperature profiles are sensitive to changes in the rmal diffusivity and perfusion parameters. This information provides t he basis for estimation of model parameters in different tissues and f or prediction of the thermal responses of these tissues.