Photoplethysmography for an independent measure of pulsatile pressure under controlled flow conditions

Njoum, Haneen; Kyriacou, Panayiotis A.

doi:10.1088/1361-6579/38/2/87

Cited by 8 publications

(9 citation statements)

References 33 publications

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“…Accompanied by the highly significant decrease in PPG AC amplitudes, there was a highly significant (p < 0.001) increase in PPG DC levels at elevated shear rates. DC levels can be seen as the light intensities resultant of the steady layer of the pulsatile flow that develops at the centre of the tube/artery and travels at the maximum velocity 31, 32 . The drop in PPG AC and the increase in PPG DC confirms that a major contributor to this behaviour is the radial migration of the erythrocytes towards the central layers of the flow.…”

Section: Discussionmentioning

confidence: 99%

Photoplethysmography for the Assessment of Haemorheology

Njoum

Kyriacou

2017

Sci Rep

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Haemorheology has been long identified as an early biomarker of a wide range of diseases, especially cardiovascular diseases. This study investigates for the first time the suitability of Photoplethysmography (PPG) as a non-invasive diagnostic method for haemorheological changes. The sensitivity of both PPG components (AC and DC) to changes in haemorheology were rigorously investigated in an in vitro experimental setup that mimics the human circulation. A custom-made reflectance PPG sensor, a pressure transducer and an ultrasonic Doppler flowmeter were used to map changes in flow dynamics and optical responses in an arterial model. The study investigated the effect of shear rates by varying fluid pumping frequencies using 4 set-points and the effect of clot formation using a chemical trigger. Both PPGAC amplitudes and PPGDC levels showed significant (p < 0.001) changes during the increase in shear rates and an immediate change after thromboplastin activation. The findings highlight that PPG has the potential to be used as a simple non-invasive method for the detection of blood characteristics, including disaggregation, radial migration and cross-linking fibrin formations. Such capability will enable the assessment of the effects of clotting-activators and anticoagulants (including non-pharmacological methods) and might aid in the early non-invasive assessment of cardiovascular pathologies.

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Section: Discussionmentioning

confidence: 99%

Photoplethysmography for the Assessment of Haemorheology

Njoum

Kyriacou

2017

Sci Rep

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“…In the literature, a pulse wave velocity (PWV) was reported to increase with the peak pressure [5]. The PWV was strongly affected by the tube elasticity and the velocity was higher on the stiff tube compared to the soft tubes [6]. In a typical blood circulatory system, the arterial compliance reduced due to a loss of vessel wall elasticity resulting in an increased in pulse wave velocity [17].…”

Section: As Shown Inmentioning

confidence: 99%

“…A phantom system is able to enhance understanding of the basic principles of a physiological system such as pulse wave propagation in a blood vessel [1] and PPG characteristics on different tissues properties [2]. A physical model of cardiovascular system has been widely developed mainly focused on a photoplethysmography (PPG) pulse waveform [3], [4] and to simulate pulse wave velocity (PWV) measurement [5], [6] leading to a pulse transit time (PTT) measurement system. A pulsatile waveform was generated either by a commercial pulsatile pump [7], [8] or custom motorised pump [9].…”

Section: Introductionmentioning

confidence: 99%

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Development of Tubular Cardiovascular Phantom System for Pulse Transit Time Simulation

2019

ijrte

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This paper presents on the development of a tubular cardiovascular phantom system to simulate pulse transit time (PTT). The PTT defined as the delay time between two pulses in one cardiac cycle has been shown to be promising method for cuffless continuous blood pressure (BP) measurement. However most of the PTT measurement was performed on human subjects, thus giving a difficulty in validating sensor performance due to variability of BP. Therefore, a cardiovascular phantom system was proposed for simulate the PTT measurement. An electronic controlled module was developed to control pump operation for pulse generation. Plastic optical fibre (POF) sensors were used to measure the pulse signal on the flexible tube and the results were compared with an in-line pressure sensor. In this experiment, the delay time between two pulses were calculated offline using Matlab software and correlated with pulse pressure. The result demonstrate that the pulse delay time recorded by both sensors decreased with increase of pulse rate and pulse pressure. These results on the phantom study showed similar pattern to the human model, thus indicating that the system is able to simulate PTT for sensor validation purposes.

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“…There has been an increased interest in the development of innovative non-invasive methods and devices for the diagnosis of CVD at an early stage in an effort to prevent further complications, and monitor pharmacological and non-pharmacological treatments [15,16] . In recent papers, we addressed the role of haemorheology in the photoplethysmographic waveform [17] , and the relationship between the photoplethysmographic signal and transmural pressure values [18] . Further waveform analysis has been used for non-invasive estimations of AS [19][20][21] .…”

Section: Introductionmentioning

confidence: 99%

In vitro validation of measurement of volume elastic modulus using photoplethysmography

Njoum

Kyriacou

2018

Medical Engineering & Physics

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Arterial stiffness (AS) is one of the earliest detectable symptoms of cardiovascular diseases and their progression. Current AS measurement methods provide an indirect and qualitative estimation of AS. The purpose of this study is to explore the utilisation of Photoplethysmography (PPG) as a measure of volumetric strain in providing a direct quantification of the Volume Elastic modulus (E). An in vitro experimental setup was designed using an arterial model to simulate the human circulation in health (Model 2) and disease (Model 1). Flow, pressure, and PPG signals were recorded continuously under varied conditions of flow dynamics. The obtained E values were validated with the gold standard mechanical testing techniques. Values obtained from both methods had no significant difference for both models with a percent error of 0.26% and 1.9% for Model 1 and Model 2, respectively. This study shows that PPG and pressure signals can provide a direct measure of AS in an in vitro setup. With emerging noninvasive pressure measurement methods, this research paves the way for the direct quantification of AS in vivo.

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Photoplethysmography for an independent measure of pulsatile pressure under controlled flow conditions

Cited by 8 publications

References 33 publications

Photoplethysmography for the Assessment of Haemorheology

Photoplethysmography for the Assessment of Haemorheology

Development of Tubular Cardiovascular Phantom System for Pulse Transit Time Simulation

In vitro validation of measurement of volume elastic modulus using photoplethysmography

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