Multi-Site Photoplethysmographic and Electrocardiographic System for Arterial Stiffness and Cardiovascular Status Assessment.

David Perpetuini,Sabina Gallina,Giorgio Fallica,Vincenzo Perciavalle,Lidia Maddiona,Arcangelo Merla,Vincenzo Vinciguerra,Francesco Bianco,Sergio Rinella,Valentina Bucciarelli,Antonio Maria Chiarelli

doi:10.3390/s19245570

Abstract

The development and validation of a system for multi-site photoplethysmography (PPG) and electrocardiography (ECG) is presented. The system could acquire signals from 8 PPG probes and 10 ECG leads. Each PPG probe was constituted of a light-emitting diode (LED) source at a wavelength of 940 nm and a silicon photomultiplier (SiPM) detector, located in a back-reflection recording configuration. In order to ensure proper optode-to-skin coupling, the probe was equipped with insufflating cuffs. The high number of PPG probes allowed us to simultaneously acquire signals from multiple body locations. The ECG provided a reference for single-pulse PPG evaluation and averaging, allowing the extraction of indices of cardiovascular status with a high signal-to-noise ratio. Firstly, the system was characterized on optical phantoms. Furthermore, in vivo validation was performed by estimating the brachial-ankle pulse wave velocity (baPWV), a metric associated with cardiovascular status. The validation was performed on healthy volunteers to assess the baPWV intra- and extra-operator repeatability and its association with age. Finally, the baPWV, evaluated via the developed instrumentation, was compared to that estimated with a commercial system used in clinical practice (Enverdis Vascular Explorer). The validation demonstrated the system’s reliability and its effectiveness in assessing the cardiovascular status in arterial ageing.

Highlights

Photoplethysmography (PPG) [1] is a noninvasive optical technique that measures local blood volume changes caused by cardiac pulse propagation into the arterial tree
The PPG signal consists of a baseline component that depends on blood volume and a modulated component at around 1 Hz caused by pulse propagation
No motion artifact, which is clear on the optical probe that was moved, can be observed on the concurrently acquired probe located on the optical probe that was moved, can be observed on the concurrently acquired probe located on the control phantom and the probe located on the subject, both in the time (Figure 6a) and in the frequency control phantom and the probe located on the subject, both in the time (Figure 6a) and in the (Figure 6b) domain

Summary

Introduction

Photoplethysmography (PPG) [1] is a noninvasive optical technique that measures local blood volume changes caused by cardiac pulse propagation into the arterial tree. This technique is an active technology that requires a source to inject light into the skin and a detector to collect photons after their propagation in biological structures. PPG measurements can be performed in transmission modality (e.g., on fingers to evaluate arterial oxygen saturation and pulse wave contours [3]) or, by exploiting the highly diffusive properties of biological tissue in the NIR spectral range, in back-reflection modality [4]. In the back-reflection configuration, the light source and the detector are placed on the same surface at an interoptode distance of few centimeters

Results

Discussion

Conclusion