Piryova B, Vrabchev N, Kurtev A
Acta Physiol Pharmacol Bulg. 1978;4(2):68-75.
The concept of the compartment structure of body fluids gives possibilities for finding the values of physiological characteristics such as volume of distribution, transport rate, kidney and intercompartment clearance. Their determination is made indirectly and it is based on the solution of a system of differential equations describing the behaviour of an open two-compartment system when an indicator substance is introduced. The determination of the coefficients of the equations involves a number of difficulties leading to inaccurate results due to the use of graphic-analytical methods. It is proposed to avoid this shortcoming by applying multiple approximation of the function describing the change in time of the concentration of the indicator substance in the intravasal space by a sum of two exponents, which corresponds to the system of differential equations. The approximation is performed by the least squares method, the precision criterion being the mean quadratic error of the approximation. An algorithm for which a computer programme is elaborated is proposed.
体液的房室结构概念为确定诸如分布容积、转运速率、肾脏及房室间清除率等生理特征值提供了可能性。这些特征值是间接确定的，其依据是描述引入指示物质时开放双房室系统行为的微分方程组的解。由于使用图形分析方法，方程组系数的确定存在诸多困难，导致结果不准确。建议通过用两个指数之和对描述指示物质在血管内空间浓度随时间变化的函数进行多重逼近的方法来避免这一缺点，这一方法与微分方程组相对应。逼近通过最小二乘法进行，精度标准为逼近的均方误差。提出了一种为此编制计算机程序的算法。
