同步测量阻抗心动图和肺阻抗血流图的原理

Theory of synchronous measuring for impedance cardiogram and impedance pneumogram

作者在Nyboer和Kubicek提出的阻抗血流图理论的基础上,考虑到肺动脉阻抗的变化,提出用同一恒流源同步测量阻抗心动图和肺阻抗血流图的原理,建立了新的物理模型和等效电路.通过分析等效电路,推导出了常数K=C(1+(d/h)~2)^(1/2)/(4π·Se).同步测量时,得到的肺阻抗血流图的参数是:K·Zor,K·△Zr,K·dZr/dt.(C是受试者剑突处的胸围,Se是肺阻抗电极的面积,d是前后肺阻抗电极之间的水平距离,h是前后肺阻抗电极的垂直距离)

The authors produced the theory of synchronous measuring for impedance cardiogram and impedance pneumogram by a constant current source. The theory is based on Nyboer's and Kubicek's theory for impedance plethysmography, considering the changes of the impedance in pulmonary artery. We built a new physical model and equivalent circut, and obtained a constant by analysising the equivalent circut. When its synchronously measured, the parameters of impedance pneumogram are K·Zor, K·△ Zr, K·dZr/dt.