Karalis Vangelis, Dokoumetzidis Aristides, Macheras Panos
Laboratory of Biopharmaceuticals-Pharmacokinetics, School of Pharmacy, University of Athens, Athens, Greece.
J Pharmacol Exp Ther. 2004 Jan;308(1):198-205. doi: 10.1124/jpet.103.058941. Epub 2003 Oct 20.
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.
指示剂稀释研究用于估算多个生理参数，如心输出量以及血管内和血管外容积。本研究介绍了一种估算再循环参数的新技术。基于由血管树的分形几何和血流动力学推导而来的弥散 - 对流偏微分方程（PDE）的数学模型，用于描述循环系统中示踪剂的时空分布。最初，将该方程拟合到示踪剂的浓度 - 时间（C，t）数据，以得出模型方程的参数估计值；在随后的步骤中，这些估计值连同PDE参数的适当变化，用于生成无再循环的假设合适示踪剂的早期浓度 - 时间分布。因此，计算示踪剂首次通过时浓度 - 时间曲线下的面积，并用于估算各种生理参数，包括心输出量、各种部分血容量以及相应的平均通过时间。该程序已成功应用于来自人类和狗的各种示踪剂的文献数据。
