Photoplethysmography in oxygenation and blood volume measurements

Abay, Tomas Ysehak; Kyriacou, P. A.

doi:10.1016/b978-0-12-823374-0.00003-7

Cited by 10 publications

(15 citation statements)

References 112 publications

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“…To our knowledge, few studies have been performed with PPG and auditory stimulation (Ooishi & Kashino, 2012). In the literature, the study of this signal has been related to changes in blood volume or BVP (Abay & Kyriacou, 2022; Grote et al, 2003). The PPG signal has been interpreted as oscillations in light scattering and absorption, due to heart‐induced blood flow changes (Nitzan & Zehava, 2022).…”

Section: Discussionmentioning

confidence: 99%

“…An additional measure of peripheral responses can be obtained using PPG. This measurement allows to record the changes in blood flow using infrared light that penetrates the tissue, usually in the finger, approximating blood volume by determining the amount of reflected light (Abay & Kyriacou, 2022). The PPG signal is used to measure blood volume pulse (BVP), which indicates variations in the volume of blood in vessels (Kushki et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

“…The PPG signal is used to measure blood volume pulse (BVP), which indicates variations in the volume of blood in vessels (Kushki et al, 2011). PPG reflects the changes in the blood volume and blood flow supplied to the region since represents the pumping action of the heart (Abay & Kyriacou, 2022). The PSD analysis of the PPG and its variability has been used as a way to study the regulation of peripheral vascular tone, taking into account that the BP oscillations are transmitted and projected into the PPG signal (Ishbulatov et al, 2020; Kiselev & Karavaev, 2020).…”

Section: Introductionmentioning

confidence: 99%

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Head hemodynamics and systemic responses during auditory stimulation

Muñoz

Diaz‐Sánchez

Muñoz-Caracuel

et al. 2022

Physiological Reports

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The present study aims to analyze the systemic response to auditory stimulation by means of hemodynamic (cephalic and peripheral) and autonomic responses in a broad range of auditory intensities (70.9, 77.9, 84.5, 89.5, 94.5 dBA). This approach could help to understand the possible influence of the autonomic nervous system on the cephalic blood flow. Twenty‐five subjects were exposed to auditory stimulation while electrodermal activity (EDA), photoplethysmography (PPG), electrocardiogram, and functional near‐infrared spectroscopy signals were recorded. Seven trials with 20 individual tones, each for the five intensities, were presented. The results showed a differentiated response to the higher intensity (94.5 dBA) with a decrease in some peripheral signals such as the heart rate (HR), the pulse signal, the pulse transit time (PTT), an increase of the LFnu power in PPG, and at the head level a decrease in oxygenated and total hemoglobin concentration. After the regression of the visual channel activity from the auditory channels, a decrease in deoxyhemoglobin in the auditory cortex was obtained, indicating a likely active response at the highest intensity. Nevertheless, other measures, such as EDA (Phasic and Tonic), and heart rate variability (Frequency and time domain) showed no significant differences between intensities. Altogether, these results suggest a systemic and complex response to high‐intensity auditory stimuli. The results obtained in the decrease of the PTT and the increase in LFnu power of PPG suggest a possible vasoconstriction reflex by a sympathetic control of vascular tone, which could be related to the decrease in blood oxygenation at the head level.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Head hemodynamics and systemic responses during auditory stimulation

Muñoz

Diaz‐Sánchez

Muñoz-Caracuel

et al. 2022

Physiological Reports

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“…Although NIRS allows the microcirculation assessment by measuring changes in the concentration of tissue oxygenated and deoxygenated hemoglobin (Hb), it requires a vascular occlusion test (VOT), which results in discontinuous measurements, in addition to the inability of reproducing this technique in other body sites that reflects visceral microcirculation state as sublingual area 13 – 15 On the other hand, the inherent barriers in the peripheral assessment of microcirculation from the finger, such as nail polish, skin color, and the influence of temperature on distal perfusion, along with the crucial relationship between visceral and sublingual microcirculation, have increased the interest in measuring and studying the latter 8 , 16 , 17 . There is growing evidence suggesting a link between sublingual microcirculation and vascular changes in shock and sepsis 9 .…”

Section: Introductionmentioning

confidence: 99%

“…[13][14][15] On the other hand, the inherent barriers in the peripheral assessment of microcirculation from the finger, such as nail polish, skin color, and the influence of temperature on distal perfusion, along with the crucial relationship between visceral and sublingual microcirculation, have increased the interest in measuring and studying the latter. 8,16,17 There is growing evidence suggesting a link between sublingual microcirculation and vascular changes in shock and sepsis. 9 Most of these results have been possible due to the introduction and evolution of videomicroscopy techniques, such as orthogonal polarization spectral imaging, sidestream dark field imaging, and incident dark field imaging, which have not only provided clearer visualization of capillaries but also improved image resolution, enabling a more precise characterization of microcirculatory changes, during various physiopathological processes.…”

mentioning

confidence: 99%

Non-invasive assessment of sublingual microcirculation using flow derived from green light PPG: evaluation and reference values

Acevedo,

Sánchez,

Londoño

et al. 2024

J. Biomed. Opt.

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The study of sublingual microcirculation offers valuable insights into vascular changes and overcomes some limitations of peripheral microcirculation assessment. Videomicroscopy and pulse oximetry have been used to assess microcirculation, providing insights into organ perfusion beyond macrohemodynamics parameters. However, both techniques have important limitations that preclude their use in clinical practice.Aim: To address this, we propose a non-invasive approach using photoplethysmography (PPG) to assess microcirculation.Approach: Two experiments were performed on different samples of 31 subjects. First, multi-wavelength, finger PPG signals were compared before and while applying pressure on the sensor to determine if PPG signals could detect changes in peripheral microcirculation. For the second experiment, PPG signals were acquired from the ventral region of the tongue, aiming to assess the microcirculation through features calculated from the PPG signal and its first derivative. Results:In experiment 1, 13 out of 15 features extracted from green PPG signals showed significant differences (p < 0.05) before and while pressure was applied to the sensor, suggesting that green light could detect flow distortion in superficial capillaries. In experiment 2, 15 features showed potential application of PPG signal for sublingual microcirculation assessment. Conclusions:The PPG signal and its first derivative have the potential to effectively assess microcirculation when measured from the fingertip and the tongue. The assessment of sublingual microcirculation was done through the extraction of 15 features from the green PPG signal and its first derivative. Future studies are needed to standardize and gain a deeper understanding of the evaluated features.

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