Extracting Venous and Respiration Signals from Photoplethysmographs

Yousefi, R.; Nourani, Mehrdad

doi:10.1109/jbhi.2014.2334697

Cited by 9 publications

(6 citation statements)

References 31 publications

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“…It is hoped that the advancements in signal processing techniques in recent years could help in overcoming this issue. In this regard, features extraction algorithms such as the one developed by Yousefi and Nourani could be used to separate the time-domain signals into their arterial and venous component [24]. This approach could be useful in isolating the venous pulsations from the forehead signals in an attempt to improve the estimation of SpO2.…”

Section: Discussionmentioning

confidence: 99%

Perfusion Changes at the Forehead Measured by Photoplethysmography during a Head-Down Tilt Protocol

2019

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Photoplethysmography (PPG) signals from the forehead can be used in pulse oximetry as they are less affected by vasoconstriction compared to fingers. However, the increase in venous blood caused by the positioning of the patient can deteriorate the signals and cause erroneous estimations of the arterial oxygen saturation. To date, there is no method to measure this venous presence under the PPG sensor. This study investigates the feasibility of using PPG signals from the forehead in an effort to estimate relative changes in haemoglobin concentrations that could reveal these posture-induced changes. Two identical reflectance PPG sensors were placed on two different positions on the forehead (above the eyebrow and on top of a large vein) in 16 healthy volunteers during a head-down tilt protocol. Relative changes in oxygenated ( Δ HbO 2 ), reduced ( Δ HHb) and total ( Δ tHb) haemoglobin were estimated from the PPG signals and the trends were compared with reference Near Infrared Spectroscopy (NIRS) measurements. Also, the signals from the two PPG sensors were analysed in order to reveal any difference due to the positioning of the sensor. Δ HbO 2 , Δ HHb and Δ tHb estimated from the forehead PPGs trended well with the same parameters from the reference NIRS. However, placing the sensor over a large vasculature reduces trending against NIRS, introduces biases as well as increases the variability of the changes in Δ HHb. Forehead PPG signals can be used to measure perfusion changes to reveal venous pooling induced by the positioning of the subject. Placing the sensor above the eyebrow and away from large vasculature avoids biases and large variability in the measurements.

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Section: Discussionmentioning

confidence: 99%

Perfusion Changes at the Forehead Measured by Photoplethysmography during a Head-Down Tilt Protocol

2019

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“…It is also important to note that the PPG signal also contains a cardio-synchronous venous component but usually this component has a relatively small amplitude compared to the rest of the signal. In a recent study (Youse and Nourani;2015) it has been shown that arterial saturation estimated at di erent breathing rate are not signi cantly a ected by this cardio-synchronous venous component. This component is also not taken into account in the estimation of SpO 2 by most commercial pulse oximeters.…”

Section: Discussionmentioning

confidence: 95%

Estimation of instantaneous venous blood saturation using the photoplethysmograph waveform

2015

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Non-invasive estimation of regional venous saturation (SxvO2) using a conventional pulse oximeter could provide a means of obtaining clinically relevant information. This study was carried out in order to investigate the hypothesis that SxvO2 could be estimated by utilising the modulations created by positive pressure ventilation in the photoplethysmograph (PPG) signals. The modulations caused by the mechanical ventilator were extracted from oesophageal PPG signals obtained from 12 patients undergoing cardiothoracic surgery. The signals analysed in this work were acquired in a previous study. For the purpose of this analysis the raw PPG signal was considered to have three major components, ac PPG signal (cardiac related component), a static component or dc PPG signal (created mostly by the absorption of light by surrounding tissue) and the ventilator modulation component. These components were then used to estimate instantaneous arterial blood oxygen saturation (SpO2) and SxvO2 by utilising time-frequency analysis technique of smoothed-pseudo Wigner–Ville distribution (SPWVD). The results showed that there was no significant difference in the traditionally-derived (time-domain) arterial saturation and the instantaneous arterial saturation. However, the instantaneous venous saturation was found to be significantly lower than the estimated time-domain and instantaneous arterial saturation (P = < 0.001, n = 12).

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“…Nowadays, PPG sensors are widely used in various physiological applications, such as monitoring heart rate [ 7 , 8 , 9 ], heart rate variability [ 10 , 11 , 12 ], blood pressure [ 13 , 14 , 15 ], and blood oxygen level [ 16 , 17 , 18 ] etc. Moreover, since the hardware of PPG sensors can be manufactured to small sizes with low cost, PPG sensors can be implemented into various wearable applications, such as bracelets [ 19 ], watches [ 20 ], patches [ 21 ], earpieces [ 22 ], rings [ 23 ], etc.…”

Section: Introductionmentioning

confidence: 99%

A Portable, Wireless Photoplethysomography Sensor for Assessing Health of Arteriovenous Fistula Using Class-Weighted Support Vector Machine

Chao

Chiang

Kao

et al. 2018

Sensors

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A portable, wireless photoplethysomography (PPG) sensor for assessing arteriovenous fistula (AVF) by using class-weighted support vector machines (SVM) was presented in this study. Nowadays, in hospital, AVF are assessed by ultrasound Doppler machines, which are bulky, expensive, complicated-to-operate, and time-consuming. In this study, new PPG sensors were proposed and developed successfully to provide portable and inexpensive solutions for AVF assessments. To develop the sensor, at first, by combining the dimensionless number analysis and the optical Beer Lambert’s law, five input features were derived for the SVM classifier. In the next step, to increase the signal-noise ratio (SNR) of PPG signals, the front-end readout circuitries were designed to fully use the dynamic range of analog-digital converter (ADC) by controlling the circuitries gain and the light intensity of light emitted diode (LED). Digital signal processing algorithms were proposed next to check and fix signal anomalies. Finally, the class-weighted SVM classifiers employed five different kernel functions to assess AVF quality. The assessment results were provided to doctors for diagonosis and detemining ensuing proper treatments. The experimental results showed that the proposed PPG sensors successfully achieved an accuracy of 89.11% in assessing health of AVF and with a type II error of only 9.59%.

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Extracting Venous and Respiration Signals from Photoplethysmographs

Cited by 9 publications

References 31 publications

Perfusion Changes at the Forehead Measured by Photoplethysmography during a Head-Down Tilt Protocol

Perfusion Changes at the Forehead Measured by Photoplethysmography during a Head-Down Tilt Protocol

Estimation of instantaneous venous blood saturation using the photoplethysmograph waveform

A Portable, Wireless Photoplethysomography Sensor for Assessing Health of Arteriovenous Fistula Using Class-Weighted Support Vector Machine

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