Simultaneous piezoelectric noninvasive detection of multiple vital signs

Areen Allataifeh,Mahmoud Al Ahmad

doi:10.1038/s41598-019-57326-6

Abstract

The monitoring of vital signs plays a key role in the diagnosis of several diseases. Piezoelectric sensors have been utilized to collect a corresponding representative signal from the chest surface. The subject typically needs to hold his or her breath to eliminate the respiration effect. This work further contributes to the extraction of the corresponding representative vital signs directly from the measured respiration signal. The contraction and expansion of the heart muscles, as well as the respiration activities, will induce a mechanical vibration across the chest wall. The induced vibration is then captured by the piezoelectric sensor placed at the chest surface, which produces an electrical output voltage signal conformally mapped with the respiration-cardiac activities. During breathing, the measured voltage signal is composed of the cardiac cycle activities modulated along with the respiratory cycle activity. A representative model that incorporates the cardiac and respiratory activities is developed and adopted. The piezoelectric and the convolution theories along with Fourier transformation are applied to extract the corresponding cardiac activity signal from the respiration signal. All the results were validated step by step by a conventional apparatus, with good agreement observed.

Highlights

Robust in extracting the respiration rate because of the difficulty of finding the RR reference value due to environmental noise[26]
The piezoelectric sensors were used in a bed-leaving detection system to monitor the vital signs of the body, such as the respiration rate, blood pressure and human body movements
This section summarizes the approaches for the extraction of the mutli vital signs parameters from the acquired piezoelectric voltage signal

Summary

Introduction

Robust in extracting the respiration rate because of the difficulty of finding the RR reference value due to environmental noise[26]. Al Ahmad et al proposed the use of a piezoelectric sheet as a contactless cardiac cycle sensor to extract heart rate and blood pressure from the measured output voltage. The proposed method utilizes the principles of the piezoelectric and convolution techniques along with Fourier transformation to extract the corresponding signal of the cardiac cycle activities from a breathing signal measured in real time.

Results

Conclusion