PT  - JOURNAL ARTICLE
AU  - Karalis, Vangelis
AU  - Dokoumetzidis, Aristides
AU  - Macheras, Panos
TI  - A Physiologically Based Approach for the Estimation of Recirculatory Parameters
AID  - 10.1124/jpet.103.058941
DP  - 2004 Jan 01
TA  - Journal of Pharmacology and Experimental Therapeutics
PG  - 198--205
VI  - 308
IP  - 1
4099  - http://jpet.aspetjournals.org/content/308/1/198.short
4100  - http://jpet.aspetjournals.org/content/308/1/198.full
SO  - J Pharmacol Exp Ther2004 Jan 01; 308
AB  - Indicator dilution studies are used to provide estimates for several physiological parameters such as cardiac output as well as intra- and extravascular volumes. This study introduces a novel technique for the estimation of recirculatory parameters. A mathematical model based on a dispersion-convection partial differential equation (PDE), derived from the fractal geometry of the vascular tree and the hydrodynamics of the blood flow, is used to describe the spatiotemporal profile of tracers in the circulatory system. Initially, the equation is fitted to concentration-time (C,t) data of a tracer to derive the parameter estimates of the model equation; in a subsequent step, these estimates along with appropriate changes of the parameters of the PDE are used to generate the early concentration-time profile of a hypothetical appropriate tracer without recirculation. Thus, the area under the concentration-time curve of the first passage of the tracer is calculated and used for the estimation of various physiological parameters, including cardiac output, miscellaneous partial blood volumes, and the corresponding mean transit times. The procedure was applied successfully to literature data of various tracers from humans and dogs. The American Society for Pharmacology and Experimental Therapeutics