用笔记本电脑构建生物阻抗记录仪——基于虚拟仪器技术

Design of impedance recording instrument of living things with notebook PC based on virtual instrumentation technology

运用虚拟仪器技术研制一种基于笔记本电脑的便捷式生物阻抗记录仪,其目的在于使医生在医学实验中可方便地测定、记录动物活体心肌组织的阻抗特性变化,以揭示生物阻抗变化与生物组织的病理特征之间的相关性。系统利用美国NI公司的虚拟仪器技术,由带PCMCIA插槽的笔记本电脑和NI多功能数据采集卡构建二线制阻抗测量系统,通过软件编程按设定的频率提供强度可控的被测生物组织激励信号,再通过DAQ采集被测生物组织的电压信号,计算测定出被测生物电阻抗(模)。此系统已经浙江省人民医院心胸外科成功地试用于动物实验中,可对心肌阻抗值变化进行全程记录,而记录数据还可进一步予以离线分析处理,因而该系统非常适用于生物阻抗变化与生物病理特征相关性的医学研究。

A design of virtual bio-impedance recording instrument with notebook computer is presented. It aims at measuring and recording the impedance changes of living tissue and then exploring the medical study of correlation between bio-impedance and pathologic characteristics of the biological tissue. Based on virtual instrumentation technology, the two-wire impedance recording system is composed of a notebook computer with PCMCIA slot and a NI multi-function data acquisition card. Through LabVIEW programming, the frequency and amplitude of the excitation signal sending to biological tissue can be defined, the response of the tissue can be measured through the DAQ acquisition, and then the biological impedance can be calculated. This system has been successfully applied to animal experiments in recording the myocardial impedance by Department of the Cardiac Surgery of Zhejiang People＇s Hospital. The recorded data can be further processed and analyzed off-line. It is confirmed that the system is suitable for medical study about the correlation between the bio-impedance changes and the bio-pathologic features of the biological tissue.