IEEE Trans Biomed Circuits Syst. 2021 Feb;15(1):143-158. doi: 10.1109/TBCAS.2021.3059211. Epub 2021 Mar 30.
Cardiovascular disease (CVD) threatens the lives of many and affects their productivity. Wearable sensors can enable continuous monitoring of hemodynamic parameters to improve the diagnosis and management of CVD. Bio-Impedance (Bio-Z) is an effective non-invasive sensor for arterial pulse wave monitoring based on blood volume changes in the artery due to the deep penetration of its current signal inside the tissue. However, the measured data are significantly affected by the placement of electrodes relative to the artery and the electrode configuration. In this work, we created a Bio-Z simulation platform that models the tissue, arterial pulse wave, and Bio-Z sensing configuration using a 3D circuit model based on a time-varying impedance grid. A new method is proposed to accurately simulate the different tissue types such as blood, fat, muscles, and bones in a 3D circuit model in addition to the pulsatile activity of the arteries through a variable impedance model. This circuit model is simulated in SPICE and can be used to guide design decisions (i.e. electrode placement relative to the artery and electrode configuration) to optimize the monitoring of pulse wave prior to experimentation. We present extensive simulations of the arterial pulse waveform for different sensor locations, electrode sizes, current injection frequencies, and artery depths. These simulations are validated by experimental Bio-Z measurements.
心血管疾病 (CVD) 威胁着许多人的生命，并影响他们的生产力。可穿戴传感器可实现对血流动力学参数的连续监测，从而改善 CVD 的诊断和管理。生物阻抗 (Bio-Z) 是一种基于动脉内血液体积变化的有效无创传感器，可监测动脉脉搏波，其电流信号在组织内具有深度穿透性。然而，测量数据会受到电极相对于动脉的位置和电极配置的显著影响。在这项工作中，我们创建了一个 Bio-Z 仿真平台，该平台使用基于时变阻抗网格的 3D 电路模型来模拟组织、动脉脉搏波和 Bio-Z 感应配置。提出了一种新方法，通过可变阻抗模型，在 3D 电路模型中准确模拟不同的组织类型，如血液、脂肪、肌肉和骨骼，以及动脉的脉动活动。该电路模型在 SPICE 中进行仿真，可用于指导设计决策（例如，相对于动脉的电极位置和电极配置），以便在实验之前优化脉搏波的监测。我们针对不同的传感器位置、电极尺寸、电流注入频率和动脉深度，对动脉脉搏波进行了广泛的仿真。这些仿真通过实验 Bio-Z 测量进行了验证。
