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Validation of a new device for photoplethysmographic measurement of multi-site arterial pulse wave velocity

Sondej Tadeusz, Jannasz Iwona, Sieczkowski Krzysztof, Dobrowolski Andrzej, Obiała Karolina, Targowski Tomasz, Olszewski Robert

Biocybernetics and Biomedical Engineering

2021

Vol. 41, no. 4

1664--1684

Pulse wave velocity (PWV) is commonly used for assessing arterial stiffness and it is a useful and accurate cardiovascular mortality predictor. Currently, many techniques and devices for PWV measurement are known, but they are usually expensive and require operator experience. One possible solution for PWV measurement is photoplethysmography (PPG), which is convenient, inexpensive and provides continuous PWV results. The aim of this paper is validation of a new device for PPG sensor-based measurement of multisite arterial PWV using a SphygmoCor XCEL (as the reference device) according to the recommendations of the Artery Society Guidelines (ASG). In this study, 108 subjects (56 men and 52 women, 20–91 years in 3 required age groups) were enrolled. The multi-site PWV was simultaneous measured by 7 PPG sensors commonly used in pulse oximetry in clinical settings. These sensors were placed on the forehead, and right and left earlobes, fingers and toes. Pulse transit time (PTT) was measured offline as the difference of time delay between two onsets of the pulse wave determined by the intersecting tangent method. The PWV was calculated by dividing the distance between PPG sensors by PTT. During PPG signals measurement, reference carotid to femoral PWV (cfPWV) was performed with a SphygmoCor XCEL system. The Pearson correlation coefficient (r) between the obtained PWV results was calculated. The Bland-Altman method was used to establish the level of agreement between the two devices. Mean difference (md) and standard deviation (SD) were also calculated. The multi-site PWV was highly correlated with accuracy at the ASG-defined level of ‘‘Acceptable” (md < 1.0 m/s and SD ≤ 1.5 m/s) with cfPWV: forehead - right toe (r = 0.75, md = 0.20, SD = 0.97), forehead - left toe (r = 0.79, md = 0.18, SD = 0.91), right ear - right toe (r = 0.79, md = 0.11, SD = 0.96), left ear - left toe (r = 0.75, md = 0.43, SD = 0.99), right ear - left toe (r = 0.78, md = 0.40, SD = 0.93), left ear - right toe (r = 0.78, md = 0.11, SD = 0.96), right finger - right toe (r = 0.66, md = 0.95, SD = 1.29), left finger - lefttoe (r = 0.67, md = 0.68, SD = 1.35). This study showed that PWV measured with the multisite PPG system, in relation to the obtained numerical values, correlated very well with that measured using the commonly known applanation tonometry method. However, it should be noted, that the measured PWV concerns the central and muscular part of the arterial tree while the cfPWV is only for the central one. The best results were obtained when the proximal PPG sensor was placed on the head (ear or forehead) and the distal PPG sensor on the toe. PPG sensors can be placed in many sites at the same time, which provides greater freedom of their configuration. Multi-site photoplethysmography is an alternative method for PWV measurement and creates new possibilities for the diagnostics of cardiovascular diseases.

Klasyfikacja szmerów oddechowych : badania pilotażowe

Stasiakiewicz Paweł, Dobrowolski Andrzej P., Olszewski Robert, Gałązka-Świderek Natalia, Targowski Tomasz, Skoczylas Agnieszka, Majka Katarzyna, Lejkowski Wojciech

Elektronika : konstrukcje, technologie, zastosowania

2019

Vol. 60, nr 2

4--12

Układ oddechowy pacjenta jest początkowo diagnozowany przy zastosowaniu stetoskopu. Osłuchowa interpretacja zjawisk fizycznych jest skomplikowana i wymaga od lekarza doświadczenia oraz predyspozycji. W niniejszym artykule zaprezentowano system pomiarowy i oprogramowanie badawcze, a także proces generacji cech dystynktywnych szmerów oddechowych różnicujących przypadki chorobowe od zdrowych. Wybrane reprezentacje stanowią obiecującą podstawę do opracowania systemu klasyfikującego wspierającego proces diagnostyczny.

Patients respiratory system is firstly diagnosed using stethoscope. Auscultatory interpretation of physical phenomena is complicated and requires from doctor experience and predisposition. This article presents measurement system and experimental software as well as distinctive feature generation process diversifying normal and pathological cases. Chosen representations of signal form a promising basis for classificatory system elaborating for supporting diagnostic process.