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Languages : en
Pages : 5
Book Description
Due to low heat conductivity of body tissue, head surface cooling methods for management of the brain temperature during medical treatments often have limited utility. As blood flow rates and surface-to-volume ratios are generally high in the extremities, heat exchange between the body and the environment through the extremities is an important path for heat exchange. This study examines the effects of cold-water extremity immersion on brain temperature by simulation modeling. The work is based on a six-cylinder thermoregulatory model that predicts human thermoregulatory responses to heat, cold, and water immersion. An arteriovenous anastomosis (AVA) response algorithm was added to the base model. Arteriovenous anastomoses are assumed to be controlled by a combination of core and skin temperatures. Our series of simulation scenarios consists of resting in a hot environment (40 degrees C, 75% relative humidity) until the brain temperature rises to 39 degrees C, then continuing the rest for 1 h under one of the following treatments: (A) no cooling; (B) hands immersed in 10 degrees C; (C) feet immersed in 10 degrees C water; (D) hands/feet immersed in 10 degrees C water. The simulation results indicate that within the first 30 min, the hands, feet, or hands/feet immersion cooling resulted in brain temperature drops of 1.7 degrees C, 2.4 degrees C, and 3.3 degrees C, respectively, which correspond to cooling rates of 0.03 degrees C/min, 0.04 degrees C/min, and 0.05 degrees C/min. The predicted values show that extremity immersion cooling is a viable mechanism for simple and effective control of brain temperature.
