Heat Exchange Methods in the Assessment of Blood Flow and Heat Production in Solid Organs

摘要: Heated thermocouples were developed for the measurement of blood flow by Gibbs.! Initially, heated thermocouple was intended to be used in intact vessels much same way as thermostromuhr. It consisted a mounted needle and an attached filament constantan wire through which constant current passed. In artificial systems, it shown that faster fluid tube, lower recorded temperature; slower fluid, higher temperature. The instrument, being needlemounted, designed inserted intravenously so measure veins. Unfortunately, proved have all disadvantages thermostromuhr, without sufficient merit its own warrant general application flowmeter. Later, applied qualitative determination change solid organs. Gibbs! Schmidt Pierson2 this method investigation central nervous system. principle use same. With steady heating current, greater past flow, Used way, instrument could give results only capable purely interpretation. More recent applications method, however, although using instruments very similar design, depend upon somewhat different treatment findings. 1952, Grayson3 showed possible thermal conductivity any tissue or material into they inserted. He able demon-