RESUMO
A microcomputer based instrument to measure effective thermal conductivity and diffusivity at the surface of a tissue has been developed. Self-heated spherical thermistors, partially embedded in an insulator, are used to simultaneously heat tissue and measure the resulting temperature rise. The temperature increase of the thermistor for a given applied power is a function of the combined thermal properties of the insulator, the thermistor, and the tissue. Once the probe is calibrated, the instrument accurately measures the thermal properties of tissue. Conductivity measurements are accurate to 2 percent and diffusivity measurements are accurate to 4 percent. A simplified bioheat equation is used which assumes the effective tissue thermal conductivity is a linear function of perfusion. Since tissue blood flow strongly affects heat transfer, the surface thermistor probe is quite sensitive to perfusion.
Assuntos
Condutividade Térmica , Termômetros , Animais , Engenharia Biomédica , Regulação da Temperatura Corporal , Temperatura Alta , Humanos , Técnicas In Vitro , Fígado/fisiologia , Perfusão , RatosRESUMO
Another report from the Institute of Medicine in March 2001 has joined a large body of literature documenting serious quality and safety problems. Eight health care leaders discuss ways in which organizations can reduce medical errors and improve patient outcomes.