Effect of Geometry and Blood Flow in Cooling of Upper Leg

Systemic hypothermia has been shown to reduce neurological damage in post-cardiac arrest patients. Reducing a patient’s core temperature to 33°C over a period of 24 to 48 hours has been shown to reduce long-term neurological damage by 16% and mortality by 14% [1]. Hypothermia is frequently induced by surface cooling, either with medical devices that circulate coolant in a pad, or ice packs. However, there is a lack of knowledge about the thermal response of tissue to localized cooling. Current thermal models are designed for determining human comfort and have not been evaluated for the targeted low temperatures required for inducing hypothermia. Metabolic heat generation and tissue perfusion rate can significantly change under low temperature, which in turn affects the overall heat flux and cooling rates.