ESTIMATION OF TOTAL ARTERIAL COMPLIANCE - AN IMPROVED METHOD AND EVALUATION OF CURRENT METHODS
ESTIMATION OF TOTAL ARTERIAL COMPLIANCE - AN IMPROVED METHOD AND EVALUATION OF CURRENT METHODS
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估计动脉总顺应性--一种改进的方法和对现有方法的评估
DOI：
10.1152/ajpheart.1986.251.3.h588
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发表时间：
1986-09-01
影响因子：
--
通讯作者：
YIN, FCP
中科院分区：
文献类型：
--
作者：
LIU, ZR;BRIN, KP;YIN, FCP
活体动脉顺应性的测定长期以来一直是生理学家感兴趣的问题。目前大多数估计这一参数的方法都假设顺应性是恒定的，即动脉压力-容量(P-V)关系是线性的，并且它们还假设舒张压下降是时间的指数函数。然而，这两个假设都值得商榷。本研究基于动脉系统的Windkesel模型提出了改进的顺应性估计方法，但该方法利用的是压力下的面积，而不是波形本身。提出了考虑线性和三种假设的非线性动脉P-V关系(指数、对数和抛物线)的公式。以充血性心力衰竭和高血压患者的数据为例。假设P-V线性关系的顺应性与仅在平均主动脉压下假设P-V非线性关系的顺应性相当接近。在舒张期末期，线性假设低估了，而在收缩峰值时，它高估了假设非线性P-V关系所获得的顺应性。更简单的线性假设仍然允许一级近似遵从性，但我们表明，在这一假设下获得遵从性的现有方法存在严重的理论和实践缺陷。我们提出的方法避免了这些缺点，主要是因为与压力波的精确指数形式的偏差对这些顺应性估计的影响比目前使用的方法小。
Determination of arterial compliance in vivo has long interested physiologists. Most current methods for estimating this parameter assume that compliance is constant, i.e., that arterial pressure-volume (P-V) relations are linear, and they also assume that diastolic aortic pressure decay is an exponential function of time. Both of these assumptions, however, are questionable. This study proposes improved methods of estimating compliance based on Windkessel model of the arterial system but which utilize the area under the pressure tracing rather than the waveform itself. Formulations accounting for both linear and three hypothetical nonlinear arterial P-V relations (exponential, logarithmic, and parabolic) are presented. Data from patients with congestive heart failure and hypertension are used for illustration. Compliances assuming linear P-V relations are reasonably close to those assuming nonlinear P-V relations only at mean aortic pressure. At end-diastolic pressure the linear assumption underestimates and at peak systolic it overestimates the compliances obtained assuming nonlinear P-V relations. The simpler linear assumption still allows a first approximation to compliance, but we show that existing methods for obtaining compliance under this assumption have severe theoretical as well as practical shortcomings. Our proposed method avoids these shortcomings primarily because deviations from an exact exponential form of the pressure wave have less influence on these compliance estimates than currently used methods.