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Proceedings ArticleDOI

Single source photoplethysmograph transducer for local pulse wave velocity measurement

TL;DR: The design and experimental validation of a novel single-source Photoplethysmograph (PPG) transducer for arterial blood pulse detection and cycle-to-cycle local PWV measurement prove the potential use of newly proposed PPG transducers in continuous cuffless BP measurement systems.
Abstract: Cuffless evaluation of arterial blood pressure (BP) using pulse wave velocity (PWV) has received attraction over the years. Local PWV based techniques for cuffless BP measurement has more potential in accurate estimation of BP parameters. In this work, we present the design and experimental validation of a novel single-source Photoplethysmograph (PPG) transducer for arterial blood pulse detection and cycle-to-cycle local PWV measurement. The ability of the transducer to continuously measure local PWV was verified using arterial flow phantom as well as by conducting an in-vivo study on 17 volunteers. The single-source PPG transducer could reliably acquire dual blood pulse waveforms, along small artery sections of length less than 28 mm. The transducer was able to perform repeatable measurements of carotid local PWV on multiple subjects with maximum beat-to-beat variation less than 12%. The correlation between measured carotid local PWV and brachial BP parameters were also investigated during the in-vivo study. Study results prove the potential use of newly proposed single-source PPG transducers in continuous cuffless BP measurement systems.
Citations
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Journal ArticleDOI
TL;DR: This paper enumerates all major local PWV measurement methods while pinpointing their salient methodological considerations and emphasizing the necessity of global standardization.
Abstract: Local pulse wave velocity (PWV) is evolving as one of the important determinants of arterial hemodynamics, localized vessel stiffening associated with several pathologies, and a host of other cardiovascular events. Although PWV was introduced over a century ago, only in recent decades, due to various technological advancements, has emphasis been directed toward its measurement from a single arterial section or from piecewise segments of a target arterial section. This emerging worldwide trend in the exploration of instrumental solutions for local PWV measurement has produced several invasive and noninvasive methods. As of yet, however, a univocal opinion on the ideal measurement method has not emerged. Neither have there been extensive comparative studies on the accuracy of the available methods. Recognizing this reality, makes apparent the need to establish guideline-recommended standards for the measurement methods and reference values, without which clinical application cannot be pursued. This paper enumerates all major local PWV measurement methods while pinpointing their salient methodological considerations and emphasizing the necessity of global standardization. Further, a summary of the advancements in measuring modalities and clinical applications is provided. Additionally, a detailed discussion on the minimally explored concept of incremental local PWV is presented along with suggestions of future research questions.

88 citations


Additional excerpts

  • ...[173], [174]....

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Journal ArticleDOI
TL;DR: This review found 13 papers that proposed novel methods using various two-channel PPG systems and signal processing techniques to acquire blood pressure using multi-site PPG that offered promising results, but also found a general lack of validation in terms of sample size and diversity of populations.
Abstract: Hypertension is one of the most prevalent diseases and is often called the “silent killer” because there are usually no early symptoms. Hypertension is also associated with multiple morbidities, including chronic kidney disease and cardiovascular disease. Early detection and intervention are therefore important. The current routine method for diagnosing hypertension is done using a sphygmomanometer, which can only provide intermittent blood pressure readings and can be confounded by various factors, such as white coat hypertension, time of day, exercise, or stress. Consequently, there is an increasing need for a non-invasive, cuff-less, and continuous blood pressure monitoring device. Multi-site photoplethysmography (PPG) is a promising new technology that can measure a range of features of the pulse, including the pulse transit time of the arterial pulse wave, which can be used to continuously estimate arterial blood pressure. This is achieved by detecting the pulse wave at one body site location and measuring the time it takes for it to reach a second, distal location. The purpose of this review is to analyze the current research in multi-site PPG for blood pressure assessment and provide recommendations to guide future research. In a systematic search of the literature from January 2010 to January 2019, we found 13 papers that proposed novel methods using various two-channel PPG systems and signal processing techniques to acquire blood pressure using multi-site PPG that offered promising results. However, we also found a general lack of validation in terms of sample size and diversity of populations.

61 citations


Cites background from "Single source photoplethysmograph t..."

  • ...[16,29,34,36], explored ways to collect multi-site PPG using only one probe on one part of the body....

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  • ...[34] N1 = 17 21–34 BP Cuff PTT (CarotidPPG to CarotidPPG) N/R r = 0....

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Proceedings ArticleDOI
01 Jul 2017
TL;DR: Results indicate that the PTT calculated from the Bio-Z and PPG sensors placed at a close distance correlates well with the more established PTT measurement using the ECG in conjunction with PPG, with correlation coefficient as high as 0.92.
Abstract: In this work we explore the viability of a multimodal sensing device that can be integrated in a wearable form factor for daily, non-invasive ambulatory blood pressure (BP) monitoring. A common approach in previous research has been to rely on measuring the pulse transit time (PTT), which has been shown to be correlated with the BP. In this work, we look into the feasibility of measuring PTT using sensors separated by a small distance on one arm so that any eventual realization of the system is convenient to wear and use over long periods of time. Moreover, we investigate the combined use of two different modalities for cardiovascular measurement: the optical photoplethysmogram (PPG) as well as the bio-potential based impedance (Bio-Z) measurement. These two modalities have been previously only studied on their own or in conjunction with the electrocardiogram (ECG) for the purpose of estimating PTT. We measure the PTT from the wrist to the finger using Bio-Z and PPG sensors, and compare it to the conventional PTT measured from the ECG to PPG at the finger, in order to prove that it can be an effective replacement for existing PTT measurement strategies. Moreover, successful measurement of PTT with two different modalities of sensors at close proximity will allow designs with multiple heterogeneous sensors on a more versatile wearable sensing platform that is optimized for power and is more robust to environmental or skin contact changes. This will enable the next generation of smart watches that capture PTT and BP. Experiments were conducted in vivo with simultaneous ECG, Bio-Z and PPG sensors, and results indicate that the PTT calculated from the Bio-Z and PPG sensors placed at a close distance correlates well with the more established PTT measurement using the ECG in conjunction with PPG, with correlation coefficient as high as 0.92.

10 citations


Cites background from "Single source photoplethysmograph t..."

  • ...Another work also showed dual PPG on the carotid artery on the neck [9]....

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Proceedings ArticleDOI
01 May 2017
TL;DR: In-vivo validation study promising the potential use of the developed accelerometer probe for cuffless evaluation of BP parameters and heartrate as a confounder of local PWV assessment was obtained.
Abstract: The velocity of propagation of arterial blood pulse signals obtained from a smaller arterial section referred as local pulse wave velocity (PWV) is an index of cardiovascular events of a particular artery. In this work, we introduce a novel design of accelerometer probe for local PWV measurement from the carotid artery. The proposed probe was developed using highly sensitive dual MEMS accelerometers. The probe design with tiny dual element sensors was capable of simultaneously acquiring acceleration signals generated due to arterial wall displacement towards the skin surface. Measurements were performed from carotid artery over a smaller arterial section of length 24 mm. The ability of the probe to acquire continuous arterial waveforms and cycle-to-cycle local PWV measurement was verified by conducting an in-vivo test in multiple subjects (11 volunteers aged between 20 – 60 years) under controlled settings. Reliable as well as repeatable signals (maximum beat-to-beat variation was less than 13%) and carotid PWV measurement with high reproducibility was obtained. A correlation examination of the local PWV with heartrate and BP was conducted during the same study. A statistically significant correlation was observed with the correlation coefficient greater than 0.78 for BP parameters and 0.66 for heartrate. In-vivo validation study promising the potential use of the developed accelerometer probe for cuffless evaluation of BP parameters and heartrate as a confounder of local PWV assessment was obtained.

6 citations


Cites background from "Single source photoplethysmograph t..."

  • ...Authors have previously reported novel designs of singlesource photoplethysmograph (PPG) [9] and magnetic plethysmograph (MPG) transducer [10] for local PWV measurement....

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  • ...Compared to MPG and PPG probes, the newly proposed design is much more suitable for small form factor, patch probe design and can be integrated into wearable devices as a wireless module....

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Proceedings ArticleDOI
01 Oct 2019
TL;DR: This research utilizes the Wireless Body Network (WBN) system, which consists of a pulse sensor as a sensor in detecting a heart rate, Bluetooth as a data transfer medium and a computer as a receiver and graphical viewer of heart rate signals.
Abstract: Detection of the heart rate is part of the examination of a person’s heart condition by knowing the level of normal heart rate. This research utilizes the Wireless Body Network (WBN) system. This system consists of a pulse sensor as a sensor in detecting a heart rate, Bluetooth as a data transfer medium and a computer as a receiver and graphical viewer of heart rate signals. Pulse sensor as a heart rate sensor works through LEDs that will emit light on parts of the body that have capillary blood vessels. The output of the pulse sensor is a photoplethysmograph (PPG) signal. Through the PPG signal, analysis of cardiac frequency will be carried out using the Fast Fourier Transform (FFT) method. Through the spectrum, we will see the shape of the normal heart rate data pattern and abnormal heart rate data. The object of research is limited to people who do not have heart disease and people who have heart disease. Based on the results of the tests conducted, the dominant frequency value for the heart rate data pattern is in the range 0.683594-0.927734 Hz. With details, for a normal heart rate is 0.732422-0.927734 Hz and an abnormal heart rate is 0.683594-0.78125 Hz.

6 citations


Cites methods from "Single source photoplethysmograph t..."

  • ...Photoplethysmograph (PPG) is used to obtain information about various things related to a person’s psychology, including monitoring heart rate, observing work and heart abnormalities, monitoring breathing and regulating oxygen content in the blood [9]....

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References
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Journal ArticleDOI
TL;DR: This review explains the conventional BP measurement methods and their limitations; presents models to summarize the theory of the PTT-BP relationship; outlines the approach while pinpointing the key challenges; and discusses realistic expectations for the approach.
Abstract: Ubiquitous blood pressure (BP) monitoring is needed to improve hypertension detection and control and is becoming feasible due to recent technological advances such as in wearable sensing. Pulse transit time (PTT) represents a well-known potential approach for ubiquitous BP monitoring. The goal of this review is to facilitate the achievement of reliable ubiquitous BP monitoring via PTT. We explain the conventional BP measurement methods and their limitations; present models to summarize the theory of the PTT-BP relationship; outline the approach while pinpointing the key challenges; overview the previous work toward putting the theory to practice; make suggestions for best practice and future research; and discuss realistic expectations for the approach.

648 citations


"Single source photoplethysmograph t..." refers background or methods in this paper

  • ...Most of the existing cuffless BP monitoring systems utilize PWV measured over a large arterial section and it requires frequent calibrations to provide continuous BP parameter values with reasonable accuracy [1]....

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  • ...It has been used in many epidemiological studies and demonstrated as the most promising surrogate parameter for cuffless evaluation of blood pressure (BP) [1]....

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Journal ArticleDOI
TL;DR: In this article, the authors propose to use the long-established, engineering term compressibility when referring to the inverse of the elastic modulus instead of using compliance and distensibility.
Abstract: The ability to characterize and quantify the elastic behavior of arteries has become increasingly important, because its application has broadened from basic physiology to clinical domains and the prediction of cardiovascular risk. Consequently, it is imperative that terminology to communicate across these disciplines is consistent and meaningful. In 1960, Peterson et al1 suggested coining a new definition of elastic modulus, the ratio of stress to strain, in terms of the pulse pressure, ΔP, and the directly measurable parameters ΔD and D (diameter). This has subsequently become known as Peterson’s modulus (Ep), where ![Formula][1] In 1975, one of us (R.G.G.)2 suggested calling the inverse of Ep the arterial compliance , C, where ![Formula][2] However, since that date, various authors have used the term distensibility for this quantity (eg, most recently O’Rourke et al3), and the term compliance has also become strongly linked with adherence to medical advice. The authors would therefore suggest that this difference in terminology is best resolved by using the long-established, engineering term compressibility when referring to the inverse of the elastic modulus.4,5 Thus, use of the well-defined, longer-established terms, elastic modulus and compressibility , would replace the need to use the terms compliance and distensibility, about whose mathematical definition some confusion exists in the literature. The classic physics of elasticity is often said to have started in 1600 with the discovery by Hooke that the ratio of stress to strain in isotropic materials, within … [1]: /embed/graphic-1.gif [2]: /embed/graphic-2.gif

119 citations


"Single source photoplethysmograph t..." refers methods in this paper

  • ...The fundamental distance-time relation and blood flow mechanics equations relating PWV and BP utilized in these measurement techniques are defined only for reflection free systems [3]....

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Journal ArticleDOI
TL;DR: A prototype skin-coupled personal wearable ambulatory pulse wave velocity (PWV) monitoring system that employs two packaged silicone-coated microelectromechanical systems (MEMS) pressure sensors for detecting blood pressure waveforms through skin surface contact in a non-invasive and continuous manner is proposed and demonstrated.
Abstract: A prototype skin-coupled personal wearable ambulatory pulse wave velocity (PWV) monitoring system is proposed and demonstrated. The system employs two packaged silicone-coated microelectromechanical systems (MEMS) pressure sensors for detecting blood pressure waveforms through skin surface contact in a non-invasive and continuous manner. The sensors are placed at two adjacent measurement points of the body, for example, the wrist or the neck, to measure blood pressure waveforms simultaneously. The measured waveforms are recorded by a data acquisition unit for signal processing and analysis. Analyzing the two waveforms can obtain the delay time between them, thus determining the local PWV. An application-specific signal processing algorithm is developed to accurately obtain the PWV. The PWV and detailed blood pressure waveforms are critical for monitoring human health condition. The prototype personal wearable monitoring system demonstrated its capability of detecting PWV of approximately 5.3 m/s at the wrist and 5.1 m/s at the neck from a volunteer. Similar tests were performed on two additional volunteers, obtaining PWV of 5.9 and 6.7 m/s, respectively, measured at the wrist.

54 citations


"Single source photoplethysmograph t..." refers result in this paper

  • ...The measured local PWV values were slightly less (2-3 m/s) than previously reported values [4]....

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Proceedings ArticleDOI
01 Nov 2008
TL;DR: In this article, the pulse wave velocity (PWV) in the carotid artery (CA) has been estimated based on ultrasound data collected by the experimental scanner RASMUS at DTU.
Abstract: The pulse wave velocity (PWV) in the carotid artery (CA) has been estimated based on ultrasound data collected by the experimental scanner RASMUS at DTU Data is collected from one test subject using a frame rate (FR) of 4000 Hz The influence of FRs is also investigated The PWV is calculated from distension wave forms (DWF) estimated using cross-correlation The obtained velocities give results in the area between 3-4 m/s, and the deviations between estimated PWV from two beats of a pulse are around 10% The results indicate that the method presented is applicable for detecting the local PWV Additional studies with data collections from several test subjects are required to determine the accuracy of the approach Based on a spectrum analysis it appears that there is no gain from using FRs above 1000 Hz, but it is shown that FRs below 1000 Hz do not give accurate PWVs

43 citations

Journal ArticleDOI
TL;DR: Both local PWV methods discussed in this letter currently do not possess this real­time feedback and, therefore, are still unable to show their full potential and could greatly benefit from real­ time beat­to­beat quality assessment, by displaying the spatiotemporal correlation coefficient.

17 citations


"Single source photoplethysmograph t..." refers background in this paper

  • ...When the propagation velocity is measured over a smaller arterial section of any superficial artery, the measured values are free from error due multiple wave reflection and distance approximations [2]....

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  • ...Whenever the measurements are performed on larger arterial sections, acquired blood pulse waveforms subjects to multiple wave reflections from various bifurcation points in the arterial tree [2]....

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