Wheeldon J, Hennes M, Link V, Stinnett H
Department of Electrical Engineering, University of North Dakota, Grand Forks 58202.
Biomed Sci Instrum. 1994;30:105-10.
An Electrical Model was developed to help identify parameters obtained from dynamic pressure data on the in vitro rat aortic artery. The data was obtained using a Multifunction Pressure Generator (MPG) and recording MPG Input Pressure (Pi) and Intraarterial Pressure (Po). Transfer functions of the form Po/Pi = (A1S+Ao)/(B2S2 + B1S+Bo) were obtained and it is necessary to link A1, Ao, B2, B1 and Bo to the Biological Parameters of Inertance (M), Vascular Resistance (R) and Compliance (C). Using the Electrical Analogs to P, M, R and C which are Voltage (V), Inductance (L), Resistance (Re), and Capacitance (Ce), an Electrical Model was built. The Electrical Model has the form Vo/Vi = (Re1S + 1/Ce)/[LS2 + (Re1 + Re2)S + 1/Ce]. Since Ao = Bo = 1 from our experimental data we multiplied the denominator and numerator by Ce to obtain Vo/Vi = (CeRe1S + 1)/[CeLS2 + Ce(Re1 + Re2)S + 1]. We then transformed our Electrical Model to its Pressure Equivalent and obtained Po/Pi = (CR2S + 1)/[CMS2 + C(R1 + R2)S + 1]. Since R2 is less than R1 + R2 we theorize that total R is composed of two viscoelastic or resistive elements R1 and R2. Using measured values of compliance it should be possible to obtain reasonable values for R1, R2 and Inertance.
开发了一种电学模型，以帮助识别从体外大鼠主动脉的动态压力数据中获得的参数。数据是使用多功能压力发生器（MPG）获取的，并记录MPG输入压力（Pi）和动脉内压力（Po）。获得了形式为Po/Pi = (A1S+Ao)/(B2S2 + B1S+Bo)的传递函数，有必要将A1、Ao、B2、B1和Bo与惯性（M）、血管阻力（R）和顺应性（C）的生物学参数联系起来。利用与P、M、R和C对应的电学模拟量，即电压（V）、电感（L）、电阻（Re）和电容（Ce），构建了一个电学模型。该电学模型的形式为Vo/Vi = (Re1S + 1/Ce)/[LS2 + (Re1 + Re2)S + 1/Ce]。由于根据我们的实验数据Ao = Bo = 1，我们将分母和分子乘以Ce以得到Vo/Vi = (CeRe1S + 1)/[CeLS2 + Ce(Re1 + Re2)S + 1]。然后我们将电学模型转换为其压力等效形式，得到Po/Pi = (CR2S + 1)/[CMS2 + C(R1 + R2)S + 1]。由于R2小于R1 + R2，我们推测总R由两个粘弹性或电阻性元件R1和R2组成。利用测量的顺应性值，应该有可能获得R1、R2和惯性的合理值。
