Influence of skin blood flow and source‐detector distance on near‐infrared spectroscopy‐determined cerebral oxygenation in humans

Hirasawa, Ai; Yanagisawa, S.; Tanaka, Naoki; Funane, Tsukasa; Kiguchi, Masashi; Sørensen, Henrik; Secher, Niels H.; Ogoh, Shigehiko

doi:10.1111/cpf.12156

Cited by 42 publications

(38 citation statements)

References 39 publications

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“…This interpretation should be experimentally quantified during LBNP with direct measures of oxygen extraction via arterialjugular venous oxygen measurements across the brain, and direct assessment of CBF [e.g., via duplex Doppler ultrasound of the extracranial vessels (46)]. Additionally, NIRS is a noninvasive method to obtain measurements of ScO 2 , and concentrations of HbO 2 and dHb within the cerebral tissue, but it also may be contaminated by changes in oxygenation of the skin (11,18,41,42). For this study, we used a spatially resolved NIRS device with four emitters that were 2.0, 2.5, 3.0, and 3.5 cm from the detector, compared with only two emitters on many other NIRS devices.…”

Section: Discussionmentioning

confidence: 99%

The role of cerebral oxygenation and regional cerebral blood flow on tolerance to central hypovolemia

Kay

Rickards

2016

American Journal of Physiology-Regulatory, Integrative and Comp

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Kay VL, Rickards CA. The role of cerebral oxygenation and regional cerebral blood flow on tolerance to central hypovolemia. Am J Physiol Regul Integr Comp Physiol 310: R375-R383, 2016. First published December 16, 2015 doi:10.1152/ajpregu.00367.2015Tolerance to central hypovolemia is highly variable, and accumulating evidence suggests that protection of anterior cerebral blood flow (CBF) is not an underlying mechanism. We hypothesized that individuals with high tolerance to central hypovolemia would exhibit protection of cerebral oxygenation (ScO2), and prolonged preservation of CBF in the posterior vs. anterior cerebral circulation. Eighteen subjects (7 male/11 female) completed a presyncope-limited lower body negative pressure (LBNP) protocol (3 mmHg/min onset rate). ScO2 (via near-infrared spectroscopy), middle cerebral artery velocity (MCAv), posterior cerebral artery velocity (PCAv) (both via transcranial Doppler ultrasound), and arterial pressure (via finger photoplethysmography) were measured continuously. Subjects who completed Ն70 mmHg LBNP were classified as high tolerant (HT; n ϭ 7) and low tolerant (LT; n ϭ 11) if they completed Յ60 mmHg LBNP. The minimum difference in LBNP tolerance between groups was 193 s (LT ϭ 1,243 Ϯ 185 s vs. HT ϭ 1,996 Ϯ 212 s; P Ͻ 0.001; Cohen's d ϭ 3.8). Despite similar reductions in mean MCAv in both groups, ScO2 decreased in LT subjects from Ϫ15 mmHg LBNP (P ϭ 0.002; Cohen's dϭ1.8), but was maintained at baseline values until Ϫ75 mmHg LBNP in HT subjects (P Ͻ 0.001; Cohen's d ϭ 2.2); ScO2 was lower at Ϫ30 and Ϫ45 mmHg LBNP in LT subjects (P Յ 0.02; Cohen's d Ն 1.1). Similarly, mean PCAv decreased below baseline from Ϫ30 mmHg LBNP in LT subjects (P ϭ 0.004; Cohen's d ϭ 1.0), but remained unchanged from baseline in HT subjects until Ϫ75 mmHg (P ϭ 0.006; Cohen's d ϭ 2.0); PCAv was lower at Ϫ30 and Ϫ45 mmHg LBNP in LT subjects (P Յ 0.01; Cohen's d Ն 0.94). Individuals with higher tolerance to central hypovolemia exhibit prolonged preservation of CBF in the posterior cerebral circulation and sustained cerebral tissue oxygenation, both associated with a delay in the onset of presyncope.posterior cerebral artery; middle cerebral artery; lower body negative pressure HEMORRHAGE DUE TO TRAUMA IS one of the leading causes of morbidity and mortality worldwide in both the civilian and military settings (1, 2, 13, 22, 32). A major factor contributing to death and disability from severe blood loss is poor tissue perfusion and oxygenation of the vital organs (1, 13, 22). Prolonged cerebral hypoperfusion can lead to neuronal cell death, and if the patient survives, long-term cognitive impairment and physical disability (32). Understanding cerebral hemodynamic responses to blood loss is an essential target for improving survival to hemorrhagic injury, and developing effective therapeutic interventions (35). As there is considerable variability in survival time following hemorrhagic injuries (40), as well as tolerance to simulated hemorrhage (7,15,24,26), it is crucial to determine the rol...

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Section: Discussionmentioning

confidence: 99%

The role of cerebral oxygenation and regional cerebral blood flow on tolerance to central hypovolemia

Kay

Rickards

2016

American Journal of Physiology-Regulatory, Integrative and Comp

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“…This assumption is supported by several research works. [57][58][59][60] Moreover, it was assumed that the fNIRS signals at each S-D distance can be expressed by the linear sum of hemoglobin change signals, which are proportional to the partial optical path length at the scalp and gray matter (GM). 61 To apply the MD-ICA method to fNIRS data, at least two kinds of S-D distance (> Xi gr ) are necessary.…”

Section: Discrimination Between Deep-and Shallow-layer Functional Neamentioning

confidence: 99%

Concurrent fNIRS-fMRI measurement to validate a method for separating deep and shallow fNIRS signals by using multidistance optodes

et al. 2015

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Abstract. It has been reported that a functional near-infrared spectroscopy (fNIRS) signal can be contaminated by extracerebral contributions. Many algorithms using multidistance separations to address this issue have been proposed, but their spatial separation performance has rarely been validated with simultaneous measurements of fNIRS and functional magnetic resonance imaging (fMRI). We previously proposed a method for discriminating between deep and shallow contributions in fNIRS signals, referred to as the multidistance independent component analysis (MD-ICA) method. In this study, to validate the MD-ICA method from the spatial aspect, multidistance fNIRS, fMRI, and laser-Doppler-flowmetry signals were simultaneously obtained for 12 healthy adult males during three tasks. The fNIRS signal was separated into deep and shallow signals by using the MD-ICA method, and the correlation between the waveforms of the separated fNIRS signals and the gray matter blood oxygenation level-dependent signals was analyzed. A three-way analysis of variance (signal depth × Hb kind × task) indicated that the main effect of fNIRS signal depth on the correlation is significant [F ð1;1286Þ ¼ 5.34, p < 0.05]. This result indicates that the MD-ICA method successfully separates fNIRS signals into spatially deep and shallow signals, and the accuracy and reliability of the fNIRS signal will be improved with the method. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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“…The subjects were in a semi-recumbent position and a custommade pneumatic headband provided with a flat cap was placed circumferentially around the head ( Fig. 1) [23]. The protuberance of the headband was positioned over the left temporal artery that bifurcates from the external carotid artery and supplies the main part of forehead.…”

Section: Experiments 1: Determination Of Individual Algorithmsmentioning

confidence: 99%

“…After a 180 s baseline period, an inflation-deflation protocol (?80 mmHg 30 s cuff inflation and 30 s cuff deflation) was repeated four times to determine an individual correction factor (a 0 ) to suppress the influence of the extracranial blood flow on the NIRS signal assuming that the cuff affects scalp and scull blood flow and not cerebral oxygenation. The cuff inflation of ?80 mmHg is enough to manipulate extracranial blood flow and affect NIRS signal non-pharmacologically without haemodynamic change [23]. Therefore, we decided to use ?80 mmHg cuff pressure for the occlusion of temporal artery to reduced extracranial blood flow and O 2 Hb surely.…”

Section: Experiments 1: Determination Of Individual Algorithmsmentioning

confidence: 99%

“…It is considered that the short source-detector distance reflects photons returning from surface layers that by subtraction, should be eliminated from the profound signal. The penetration depth of the photons is proportional to the source-detector distance but SkBF equally affects NIRS with source-detector distances from 15 to 30 mm [23]. Therefore, an increase in the source-detector distance is required without attenuating the signal to noise ratio significantly [24] and the majority of NIRS devices employ a source-detector distance of 40 mm (e.g.…”

Section: Introductionmentioning

confidence: 99%

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Near-infrared spectroscopy determined cerebral oxygenation with eliminated skin blood flow in young males

Hirasawa

Kaneko

Tanaka

et al. 2015

J Clin Monit Comput

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We estimated cerebral oxygenation during handgrip exercise and a cognitive task using an algorithm that eliminates the influence of skin blood flow (SkBF) on the near-infrared spectroscopy (NIRS) signal. The algorithm involves a subtraction method to develop a correction factor for each subject. For twelve male volunteers (age 21 ± 1 yrs) +80 mmHg pressure was applied over the left temporal artery for 30 s by a custom-made headband cuff to calculate an individual correction factor. From the NIRS-determined ipsilateral cerebral oxyhemoglobin concentration (O2Hb) at two source-detector distances (15 and 30 mm) with the algorithm using the individual correction factor, we expressed cerebral oxygenation without influence from scalp and scull blood flow. Validity of the estimated cerebral oxygenation was verified during cerebral neural activation (handgrip exercise and cognitive task). With the use of both source-detector distances, handgrip exercise and a cognitive task increased O2Hb (P < 0.01) but O2Hb was reduced when SkBF became eliminated by pressure on the temporal artery for 5 s. However, when the estimation of cerebral oxygenation was based on the algorithm developed when pressure was applied to the temporal artery, estimated O2Hb was not affected by elimination of SkBF during handgrip exercise (P = 0.666) or the cognitive task (P = 0.105). These findings suggest that the algorithm with the individual correction factor allows for evaluation of changes in an accurate cerebral oxygenation without influence of extracranial blood flow by NIRS applied to the forehead.

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Influence of skin blood flow and source‐detector distance on near‐infrared spectroscopy‐determined cerebral oxygenation in humans

Cited by 42 publications

References 39 publications

The role of cerebral oxygenation and regional cerebral blood flow on tolerance to central hypovolemia

The role of cerebral oxygenation and regional cerebral blood flow on tolerance to central hypovolemia

Concurrent fNIRS-fMRI measurement to validate a method for separating deep and shallow fNIRS signals by using multidistance optodes

Near-infrared spectroscopy determined cerebral oxygenation with eliminated skin blood flow in young males

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