A Multichannel Real-Time Bioimpedance Measurement Device for Pulse Wave Analysis

TL;DR

This paper introduces a multichannel, real-time bioimpedance measurement device designed for pulse wave analysis, capable of simultaneous multi-channel impedance acquisition with high accuracy, suitable for cardiovascular monitoring.

Contribution

It presents a novel microcontroller-based system that enables simultaneous multi-channel bioimpedance measurements with high speed and signal quality for pulse wave analysis.

Findings

System can acquire 1000 impedances per second per channel.

Demonstrated capability to analyze pulse wave morphology and velocity.

First human subject measurements validate system applicability.

Abstract

Pulse wave analysis is an important method used to gather information about the cardiovascular system. Instead of detecting the pulse wave via pressure sensors, bioimpedance measurements can be performed to acquire minuscule changes in the conductivity of the tissue, caused by the pulse wave. This work presents a microcontroller-based bioimpedance measurement system, which has the capability to acquire impedance measurements from up to four independent channels simultaneously. By combining a problem-specific analog measurement circuit with a 24 bits analog-to-digital converter, the system is capable of acquiring 1000 impedances per second with a signal-to-noise ratio in a range from 92 to 96 dB. For data storage and analysis, the digitized data are sent via universal serial bus to a host PC. A graphical user interface filters and plots the data of all channels in real-time. The performance of the system regarding measuring constant impedances, as well as impedance changes over time is demonstrated. Two different applications for pulse wave analysis via multichannel bioimpedance measurements are presented. Additionally, first measurement results from a human subject are shown to demonstrate the system's applicability of analyzing the pulse wave morphology as well as the aortic pulse wave velocity.