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Non-invasive waveform analysis for emergency triage via simulated hemorrhage: An experimental study using novel dynamic lower body negative pressure model

Nesaragi Naimahmed, Høiseth Lars Øivind, Qadir Hemin Ali, Rosseland Leiv Arne, Halvorsen Per Steinar, Balasingham Ilangko

Biocybernetics and Biomedical Engineering

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2023

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Vol. 43, no. 3

551--567

EN

The extent to which advanced waveform analysis of non-invasive physiological signals can diagnose levels of hypovolemia remains insufficiently explored. The present study explores the discriminative ability of a deep learning (DL) framework to classify levels of ongoing hypovolemia, simulated via novel dynamic lower body negative pressure (LBNP) model among healthy volunteers. We used a dynamic LBNP protocol as opposed to the traditional model, where LBNP is applied in a predictable step-wise, progressively descending manner. This dynamic LBNP version assists in circumventing the problem posed in terms of time dependency, as in real-life pre-hospital settings intravascular blood volume may fluctuate due to volume resuscitation. A supervised DL-based framework for ternary classification was realized by segmenting the underlying noninvasive signal and labeling segments with corresponding LBNP target levels. The proposed DL model with two inputs was trained with respective time–frequency representations extracted on waveform segments to classify each of them into blood volume loss: Class 1 (mild); Class 2 (moderate); or Class 3 (severe). At the outset, the latent space derived at the end of the DL model via late fusion among both inputs assists in enhanced classification performance. When evaluated in a 3-fold cross-validation setup with stratified subjects, the experimental findings demonstrated PPG to be a potential surrogate for variations in blood volume with average classification performance, AUROC: 0.8861, AUPRC: 0.8141, F1-score:72.16%, Sensitivity:79.06%, and Specificity:89.21%. Our proposed DL algorithm on PPG signal demonstrates the possibility to capture the complex interplay in physiological responses related to both bleeding and fluid resuscitation using this challenging LBNP setup.

2

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

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2021

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Vol. 41, no. 4

1664--1684

EN

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.

3

Wbudowane w odzież urządzenie do monitorowania parametrów życiowych

Nowosielski Leszek, Dudziński Bartosz

Elektronika : konstrukcje, technologie, zastosowania

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2020

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Vol. 61, nr 8

15--19

PL

W artykule opisano podstawowe parametry życiowe człowieka takich jak: tętno, temperatura ciała, poziom napięcia mięśniowego, oddech i ciśnienie krwi. W artykule przedstawiono schemat blokowy oraz ideowy systemu monitorującego parametry życiowe wraz z algorytmem oprogramowania urządzenia. Przedstawiono przykładowe wyniki pomiarów.

EN

The article describes basic human life parameters such as: heart rate, body temperature, muscle tension, breathing and blood pressure. The article presents a block diagram and electrical diagram system for monitoring vital parameters along with the device software algorithm. Sample measurement results are presented.

4

Detekcja rzutu kośćmi do gry z użyciem sieci neuronowych

Szadkowski Rafał Maciej, Dąbal Paweł

Elektronika : konstrukcje, technologie, zastosowania

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2020

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Vol. 61, nr 7

26--29

PL

Sztuczne sieci neuronowe stanowią obszerny zbiór zagadnień, które mogą być użyte w wielu dziedzinach nauki. Bardzo popularnym ich zastosowaniem jest przetwarzanie i kategoryzacja obrazów. W artykule tym opisano w jaki sposób wykonano i przebadano praktyczną realizację klasyfikatora obiektów z użyciem tychże sieci. Opisany został problem klasycznego detektora obiektów, który następnie posłużył do przygotowania bazy treningowej, ale również jako składowa ostatecznej implementacji algorytmu. Przedstawiono również w jaki sposób przygotowane zostały dane treningowe użyte do wyszkolenia sieci oraz w jaki sposób została wybrana architektury sieci neuronowej. W ostatniej części przedstawiono wyniki przeprowadzonych badań. Wskazano zaobserwowane wady i zalety takiego podejścia do rozwiązania problemu.

EN

Neural networks are very broad research issue, they find their way into many fields of science. Probably their most popular implementation is met in image processing and classification. This paper describes how to practically implement such classifier based on neural networks. First part describes classical object detector, used later to build a training data set, but also as a part of final product used to process images. Paper describes how aforementioned data set was prepared and how architecture of neural network has been chosen. In the last part there are result of run tests, as well as pros and cons of such solution to the problem.

5

Wyznaczanie czasu propagacji Fali tętna w oparciu o sygnały EKG i PPG

Sieczkowski Krzysztof, Dobrowolski Andrzej P., Sondej Tadeusz, Olszewski Robert

Przegląd Elektrotechniczny

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2019

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R. 95, nr 11

101--104

PL

W artykule przedstawiono nowatorską metodę pozwalającą na wyznaczanie czasów propagacji fali tętna, która bazuje na jednoczesnym pomiarze sygnałów EKG i PPG. Kluczowa dla proponowanego algorytmu dokładność wyznaczenia początkowego i końcowego punktu pomiarowego danego sygnału, silnie zależy od procedur wstępnego przetwarzania. Proponowane rozwiązanie opiera się na rozwijanej przez autorów metodzie korelacji aktualizowanego na bieżąco wzorca sygnału z aktualnie analizowanym fragmentem sygnału.

EN

In this article was presented a novel method for determining a pulse transit time, which is based on simultaneous measurement of ECG and PPG signals. The key to the proposed algorithm, the accuracy of determining the starting and ending measuring point of a given signal, strongly depends on the pre-processing procedures. The proposed solution is based on the method of correlation of the currently updated signal pattern with the currently analyzed fragment of signal, developed by the authors.

6

Calibration of the metrological characteristics of photoplethysmographic multispectral device for diagnosis the peripheral blood circulation

Pavlov S. V., Kozlovska T. I., Sydoruk O. O., Kotovskyy V. I., Wójcik W., Orakbayev Y.

Przegląd Elektrotechniczny

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2017

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R. 93, nr 5

79--82

EN

This paper presents firstly-engineered photoplethysmographic multispectral device for diagnosis the peripheral blood circulation. The calculation of the main errors as: primary converter error, methodical error of measurement, setting of optical-electronic sensor error was carried out. Moreover the assessment of reliability of diagnosis the engineered device was conducted.

PL

Artykuł prezentuje pierwsze rozwiązanie wielospektralnego urządzenia fotopletyzmograficzego do diagnostyki obwodowego przepływu krwi. Przeprowadzono obliczenia głównych błędów: podstawowego błędu przetwarzania, błędu metodyki pomiaru, ustalonego błędu przetwornika optoelektronicznego. Ponadto przeprowadzono ocenę niezawodności zaprojektowanego urządzenia.

7

Analysis of the vascular tone and character of the local blood flow to assess the viability of the body using the photoplethysmographic device

Zlepko S. M., Sander S. V., Kozlovska T. I., Pavlov S. V., Wójcik W., Yesmakhanova L., Zhirnova O.

Przegląd Elektrotechniczny

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2017

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R. 93, nr 5

92--95

EN

The paper evaluated the vascular tone and character of the local blood flow using photoplethysmographic device to determine the viability of the studied organ and prospects for its preservation.

PL

W pracy przedstawiono ocenę sygnału naczyniowego i charakter lokalnego przepływu krwi z użyciem urządzeń fotopletyzmograficznych do oceny żywotności badanego narządu i perspektywy jego zachowania.

8

Distant Measurement of Plethysmographic Signal in Various Lighting Conditions Using Configurable Frame-Rate Camera

Przybyło J., Kańtoch E., Jabłoński M., Augustyniak P.

Metrology and Measurement Systems

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2016

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Vol. 23, nr 4

579--592

EN

Videoplethysmography is currently recognized as a promising noninvasive heart rate measurement method advantageous for ubiquitous monitoring of humans in natural living conditions. Although the method is considered for application in several areas including telemedicine, sports and assisted living, its dependence on lighting conditions and camera performance is still not investigated enough. In this paper we report on research of various image acquisition aspects including the lighting spectrum, frame rate and compression. In the experimental part, we recorded five video sequences in various lighting conditions (fluorescent artificial light, dim daylight, infrared light, incandescent light bulb) using a programmable frame rate camera and a pulse oximeter as the reference. For a video sequence-based heart rate measurement we implemented a pulse detection algorithm based on the power spectral density, estimated using Welch’s technique. The results showed that lighting conditions and selected video camera settings including compression and the sampling frequency influence the heart rate detection accuracy. The average heart rate error also varies from 0.35 beats per minute (bpm) for fluorescent light to 6.6 bpm for dim daylight.

9

Noninvasive monitoring with strongly absorbed light

McEwen M P, Reynoldsk J

Optica Applicata

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2014

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Vol. 44, nr 2

177--190

EN

The transmission of light through tissue is used in noninvasive monitoring, in particular photoplethysmography. Investigations involving the transmission of wavelengths absorbed by bilirubin (short wavelength visible light) have been limited, due to strong absorption by haemoglobin. Achieving transmission of these wavelengths through tissue may advance noninvasive monitoring of substances like bilirubin. This work investigates the use of high power light sources together with improvements in signal-to-noise ratio as a means of enabling the transmission of strongly absorbed light through tissue. A custom device using multiple high-power short-wavelength visible light sources together with low power red and infrared sources, and background light cancellation – to improve signal-to-noise ratio, was constructed. Transmission of 454–1200 nm light through tissue was achieved, with pulsations present in measured signals. The transmission through tissue of multiple wavelengths of strongly absorbed light can be achieved by using high power light sources in conjunction with cancelling the effect of background light. Use of these techniques may allow investigations into the noninvasive monitoring of substances such as bilirubin using photoplethysmography.

10

Pomiary fotopulsoksymetryczne przy występowaniu zakłóceń wywołanych czynnościami ruchowymi : rozwiązania układowe

Torbicz W., Dawgul M., Dudziński K., Wawro B., Remiszewska E., Pijanowska D. G.

Elektronika : konstrukcje, technologie, zastosowania

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2014

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Vol. 55, nr 11

76-84

PL

Obecnie istnieje coraz szersze zapotrzebowanie na urządzenia służące do oceny stanu psychofizycznego osób, w tym żołnierzy czy sportowców, w czasie ich aktywności fizycznej, a więc w ruchu. Muszą to być przyrządy noszone. Ruch ciała jest źródłem dużych zakłóceń, które utrudniają, a nawet uniemożliwiają wykonanie pomiarów za pomocą pulsoksymetrów stosowanych w diagnostyce klinicznej. W artykule w sposób skrótowy przedstawiono zasadę pomiarów utlenowania krwi tętniczej za pomocą fotopulsoksymetrów oraz dokonano przeglądu metod przetwarzania rejestrowanych sygnałów pulsoksymetrycznych mających na celu wyeliminowanie wpływu zakłóceń ruchowych na wyniki pomiarów utlenowania krwi tętniczej.

EN

Now-a-day, there is an increasing demand for devices needed for assessing a psychophysical state of people, including soldiers and sportsmen, during their physical activity, and so in moving. Such devices must be worn. Body movement is a source of high disturbances, which impede or even make impossible realization of measurements by pulse oximeters applied in clinical diagnosis. The paper briefly presents basic information on arterial blood oxygen saturation measurements using pulse oximeters, and gives a review of methods used for processing the monitored pulse oximeter signals in order to eliminate an influence of the movement disturbances on the results of oxygen arterial blood saturation measurements.

11

Hybrydowy model drzewa naczyniowego przedramienia w ocenie obwodowej saturacji krwi żylnej

Nowocień S.

Pomiary Automatyka Kontrola

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2013

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R. 59, nr 3

270--272

PL

W artykule zaprezentowano hybrydowy model drzewa naczyń krwionośnych przedramienia, uwzględniający w swojej strukturze klasyczne analogie hydrauliczno-elektryczne w połączeniu z interakcją światło-tkanki. Prezentowany model unifikuje propozycje literaturowe i pozwala na symulację i ocenę szerszej gamy zjawisk występujących w obiekcie badanym. Potrzeba opracowania modelu podyktowana była niejednoznacznościami wskazań obecnie stosowanych przyrządów do oceny regionalnej saturacji krwi żylnej (rSvO2), połączoną ze stale rosnącym zakresem ich zastosowań. Prezentowany model, w przeciwieństwie do modeli dostępnych w literaturze, pozwala na symulację zachowania układu krwionośnego przedramienia zarówno z punktu widzenia mechaniki drzewa naczyniowego, jak również efektów wpływu jej zmian na kształt rejestrowanych sygnałów fotopletyzmograficznych.

EN

This paper presents a hybrid model of the forearm vascular tree taking into account classical hydro-electric analogy in association with light tissue interaction in its structure. The new model unifies the literature proposals and allows simulating and evaluating a wider range of phenomena occurring in the facility under consideration. The need to develop the model was dictated by the ambiguities of indications of currently used instruments for assessing the regional oxygen saturation of venous blood (rSvO2) connected with increasing range of applications of these instruments. The model presented in this work, in contrast to the models available in the literature, allows simulating the behavior of the forearm blood from the point of view of both mechanics of the vascular tree and impact of the mechanics of the recorded photo plethysmographic signals. The field of optical phenomena in the transilumination area was modeled by a modified Lambert-Beer equation, typically used in pulse oximetry. In that case the transilumination coefficient recorded by a detector reflects changes in the effective optical path in the investigating area and depends directly on oxygenation. Scattering of light on the boundaries (emitter - air - skin) was omitted in the proposed model.

12

Wieloczujnkowy system do badania sygnału fotopletyzmograficznego

Prokop D.

Elektronika : konstrukcje, technologie, zastosowania

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2009

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Vol. 50, nr 5

98-102

PL

W pracy zaprezentowano wieloczujnikowy układ do badania sygnału fotopletyzmograficznego (PPG). Dokonano analizy zjawisk fizycznych towarzyszących pozyskiwaniu sygnałów optycznych z obiektów biologicznych. Zaprojektowano i wykonano odbiciowe czujniki optoelektroniczne oraz układ kondycjonowania i akwizycji sygnałów PPG. Zaprezentowano przebiegi czasowe otrzymanych sygnałów.

EN

The subject matter of the paper refers to a multisensor system for examination of a photoplethysmographic signal (PPG). Biophysical phenomena connected with acquiring the optical signals from a human subject are analyzed. A reflectance variant of the optoelectronic sensors as well as conditioning system have been designed. Some selected examples of the PPG waveform obtained and analysis of their parameters are shown.

13

Wyznaczanie czasu propagacji fali tętna obwodowego

Wilk B.

Pomiary Automatyka Kontrola

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2008

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R. 54, nr 12

831-833

PL

W artykule zaprezentowano metodę wyznaczania czasu propagacji fali tętna obwodowego (ang. pulse transit time, PTT), zdefiniowanego jako przedział czasu mierzony od początku fazy skurczu serca do momentu pojawienia się tzw. ramienia wstępującego fali tętna. W metodzie tej wykorzystano sygnał fotopletyzmograficzny (PPG) reprezentujący falę tętna obwodowego oraz sygnał fonokardiograficzny (FKG), który umożliwia detekcję faz skurczu i rozkurczu w każdym cyklu pracy serca. W artykule podano także przykłady wykorzystania parametru PTT w diagnostyce medycznej.

EN

In the paper the method for determination of peripheral pulse wave transit time (PTT) (defined as the time delay between the onset of a pulse wave and the systolic period) is presented. This method is based on two signals: photoplethysmographic (PPG) and phonocardiographic (PCG). The PPG signal represents the peripheral pulse wave, while the PCG signal allows detection of the systolic and diastolic phase in each cardiac cycle. The examples of using PTT in medical diagnostics are also given.

14

Vibration syndrome diagnosis using cooling test verified by computerised photoplethysmography

Dyszkiewicz A., Tendera M.

Acta of Bioengineering and Biomechanics

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2004

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Vol. 6, nr 2

33-41

EN

This study addresses itself to the problem of vibration syndrome diagnosis by means of photoplethysmography. The measurement was performed on a small area on the finger-tip plexus in which many arteriovenous anastomoses are present. In the opinion of many authors, flow disorders in this area are more typical of developing vibration syndrome than changes in the microvessels. Cooling test was then performed and it was verified both visually and using the computer method, allowing the functional measurement of the flow to be obtained. Computer method proved to be much more sensitive than traditional tests. The test proposed allows us to detect vascular disorders in the prodromal period and gives time for preventive measures to be taken.