Analysis of the arterial pressure-volume curve in the three-element windkessel model

A one-step computational procedure is presented for estimating the parameters of the nonlinear three-element windkessel model of the arterial system incorporating a pressure-dependent compliance. Starting from steady-state aortic pressure and flow curves and under generally accepted assumptions, arterial pressure-volume curve, peripheral and characteristic resistances are determined through simple closed-form formulas. The method is applied to both simulated and experimental data and the results are compared with those obtained by an iterative parameter optimization algorithm and possibly with actual values. A major conclusion is that in most cases considered in this study a constant compliance remains an approximation of the compliant element adequate to usual measurement and model errors