基于小型电极的新型阻抗血流图测量系统的研究

Study on a New Type Impedance Blood Flow Measurement System Based on Integrative Miniature Electrodes

目的研制基于小型一体化生物电阻抗电极的用于多部位阻抗血流图检测的仪器,用于检测手腕、颈、脑等多部位阻抗血流图和评价运动负荷状态下组织中阻抗血流图的变化。方法采用高共模抑制比的差动放大器和相关检测原理对小型电极提取的微弱信号进行处理,设计相应的电路,提高信噪比,实现阻抗血流小型传感器微弱信号的检测。结果经过实验验证,该仪器能够提取手腕、颈、脑等部位的阻抗血流信号,应用相干检测技术得到了很高的信噪比,测量方便,可以进行连续监测。结论该仪器能够检测人体不同部位阻抗血流信号的搏动分量和非搏动性的直流分量,更好地评价局部血液循环状况,并且有望对运动负荷状态下的阻抗血流动力学参数作出评价。

Objective To develop an impedance blood flow measurement system based on integrative and miniature electrodes,which could be used at wrist,neck,brain and so on to measure pulsatile component of artery and nonpulsatile components including body fluid change and blood volume of other tissues such as muscle and microvessels. Method Weak signal was processed by using differential amplifier with high common mode resistance ratio （CMRR） and phase sensitive demodulation technique which can improve signal to noise ratio （SNR） greatly. Then a corresponding circuit was designed to measure effective signal and realize impedance blood flow measurement based on miniature electrodes. Result Impedance blood flow of wrist, neck, brain and so on were detected with high SNR and simple manipulation by continuously applying phase sensitive demodulator technique. Conclusion The pulsatile and nonpulsatile components of impedance blood flow at different parts of body can be detected during rest and exercise. It provides for the data evaluation of hemodynamics parameters of impedance blood flow under exercise condition.