Human calf microvascular compliance measured by near-infrared spectroscopy

2000 ◽  
Vol 88 (2) ◽  
pp. 369-372 ◽  
Author(s):  
T. Binzoni ◽  
V. Quaresima ◽  
M. Ferrari ◽  
E. Hiltbrand ◽  
P. Cerretelli
Keyword(s):  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Region Of Interest ◽  
Venous System ◽  
Vasomotor Response ◽  
Head Up Tilt ◽  
Nirs Data ◽  
The Subject ◽  
Human Calf

The purpose of this study is to develop a new method for the measurement in humans of the compliance of the microvascular superficial venous system of the lower limb by near-infrared spectroscopy (NIRS). This method is complementary to strain-gauge plethysmography, which does not allow compliance between deep and superficial venous or between venous and arterial compartments to be distinguished. In practice, hydrostatic pressure (P) changes were induced in a calf region of interest by head-up tilt of the subject from α = −10 to 75°. For P ≤ 24 mmHg, the measured compliance [0.086 ± 0.005 (SD) ml ⋅ l− 1 ⋅ mmHg− 1] based on NIRS data of total, deoxygenated, and oxygenated hemoglobin, reflects essentially that of the superficial venous system. For P ≥ 24 mmHg, no distinction can be made between arterial and venous volumes changes. However, by following the changes in oxy- and deoxyhemoglobin in the P range −16 to 100 mmHg, it appears to be possible to assess the characteristics of the vasomotor response of the arteriolar system.

Noninvasive measurement of forearm blood flow and oxygen consumption by near-infrared spectroscopy

1994 ◽  
Vol 76 (3) ◽  
pp. 1388-1393 ◽  
Author(s):  
R. A. De Blasi ◽  
M. Ferrari ◽  
A. Natali ◽  
G. Conti ◽  
A. Mega ◽  
...  
Keyword(s):  
Blood Flow ◽  
Oxygen Consumption ◽  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Healthy Subjects ◽  
Near Infrared ◽  
Forearm Blood Flow ◽  
Vascular Occlusion ◽  
Venous Occlusion ◽  
The Subject

We applied near-infrared spectroscopy (NIRS) for the simultaneous measurement of forearm blood flow (FBF) and oxygen consumption (VO2) in the human by inducing a 50-mmHg venous occlusion. Eleven healthy subjects were studied both at rest and after hand exercise during vascular occlusion. FBF was also measured by strain-gauge plethysmography. FBF measured by NIRS was 1.9 +/- 0.8 ml.100 ml-1.min-1 at rest and 8.2 +/- 2.9 ml.100 ml-1.min-1 after hand exercise. These values showed a correlation (r = 0.94) with those obtained by the plethysmography. VO2 values were 4.6 +/- 1.3 microM O2 x 100 ml-1.min-1 at rest and 24.9 +/- 11.2 microM O2 x 100 ml-1.min-1 after hand exercise. The scatter of the FBF and VO2 values showed a good correlation between the two variables (r = 0.93). The results demonstrate that NIRS provides the particular advantage of obtaining the contemporary evaluation of blood flow and VO2, allowing correlation of these two variables by a single maneuver without discomfort for the subject.

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

Biosensors ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 71
Author(s):  
Tomas Ysehak Abay ◽  
Kamran Shafqat ◽  
Panayiotis A. Kyriacou
Keyword(s):  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Arterial Oxygen Saturation ◽  
Venous Blood ◽  
Arterial Oxygen ◽  
Large Variability ◽  
Large Vein ◽  
The Subject ◽  
Induced Changes

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.

A Review of Process near Infrared Spectroscopy: 1980–1994

1993 ◽  
Vol 1 (4) ◽  
pp. 221-245 ◽  
Author(s):  
Jerry Workman
Keyword(s):  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Literature Search ◽  
Near Infrared ◽  
Process Analysis ◽  
The State ◽  
Chronological Order ◽  
Measurement Scheme ◽  
The Subject

For this review, papers on NIR process analysis were categorised according to their overall configuration and measurement scheme. This analyser taxonomy was chosen to demonstrate the state of the current use of process analyser terms and to allow the reader to access a broad range of applications by referring to the specific measuring characteristics of the analyser. The basis for this review was a literature search covering the period from January 1980 to January 1994 on the subject of Process NIR and FT-NIR analysis. Each section is in chronological order to allow the reader to observe the development (and refinement) of process NIR from 1980 to the present.

scholarly journals Algorithm construction methodology for diagnostic classification of near-infrared spectroscopy data

2011 ◽  
Vol 25 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Ramón Guevara ◽  
Lynn Stothers ◽  
Andrew Macnab
Keyword(s):  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Pelvic Floor Muscle ◽  
Classification And Regression Tree ◽  
Data Sets ◽  
Linear Discriminant ◽  
Cart Analysis ◽  
Chromophore Concentration ◽  
Nirs Data

Background: Near-infrared spectroscopy (NIRS) has recognized potential but limited application for non-invasive diagnostic evaluation. Data analysis methodology that reproducibly distinguishes between the presence or absence of physiologic abnormality could broaden clinical application of this optical technique.Methods: Sample data sets from simultaneous NIRS bladder monitoring and invasive urodynamic pressure-flow studies (UDS) are used to illustrate how a diagnostic algorithm is constructed using classification and regression tree (CART) analysis. Misclassification errors of CART and linear discriminant analysis (LDA) are computed and examples of other urological NIRS data likely amenable to CART analysis presented.Results: CART generated a clinically relevant classification algorithm (error 4%) using 46 data sets of changes in chromophore concentration composed of the whole time series without specifying features. LDA did not (error 16%). Using CART NIRS data provided comparable discriminant ability to the UDS diagnostic nomogram for the presence or absence of obstructive pathology (88% specificity, 84% precision). Pilot data examples from children with and without voiding dysfunction and women with mild or severe pelvic floor muscle dysfunction also show potentially diagnostic differences in chromophore concentration.Conclusions: CART analysis can likely be applied in other NIRS monitoring applications intended to classify patients into those with and without pathology.

scholarly journals Understanding near infrared spectroscopy and its application to skeletal muscle research

2019 ◽  
Vol 126 (5) ◽  
pp. 1360-1376 ◽  
Author(s):  
Thomas J. Barstow
Keyword(s):  
Skeletal Muscle ◽  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Oxygen Delivery ◽  
Near Infrared ◽  
Control Mechanisms ◽  
Oxygen Utilization ◽  
Muscle Research ◽  
Athletic Field ◽  
Nirs Data

Near infrared spectroscopy (NIRS) is a powerful noninvasive tool with which to study the matching of oxygen delivery to oxygen utilization and the number of new publications utilizing this technique has increased exponentially in the last 20 yr. By measuring the state of oxygenation of the primary heme compounds in skeletal muscle (hemoglobin and myoglobin), greater understanding of the underlying control mechanisms that couple perfusive and diffusive oxygen delivery to oxidative metabolism can be gained from the laboratory to the athletic field to the intensive care unit or emergency room. However, the field of NIRS has been complicated by the diversity of instrumentation, the inherent limitations of some of these technologies, the associated diversity of terminology, and a general lack of standardization of protocols. This Cores of Reproducibility in Physiology (CORP) will describe in basic but important detail the most common methodologies of NIRS, their strengths and limitations, and discuss some of the potential confounding factors that can affect the quality and reproducibility of NIRS data. Recommendations are provided to reduce the variability and errors in data collection, analysis, and interpretation. The goal of this CORP is to provide readers with a greater understanding of the methodology, limitations, and best practices so as to improve the reproducibility of NIRS research in skeletal muscle.

Near-Infrared Spectroscopy: A Tool for Diagnosing Necrotizing Enterocolitis at Onset of Symptoms in Preterm Neonates with Acute Gastrointestinal Symptoms?

2020 ◽  
Author(s):  
Julia Le Bouhellec ◽  
Olivier Prodhomme ◽  
Thibault Mura ◽  
Aurélien Jacquot ◽  
Clémentine Combes ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Necrotizing Enterocolitis ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Cerebral Oxygenation ◽  
Gastrointestinal Symptoms ◽  
Abdominal Distension ◽  
Tissue Oxygen Saturation ◽  
Preterm Neonates ◽  
Nirs Data

Abstract Objective In premature neonates, bloody stools and/or abdominal distension with feeding intolerance may be inaugural signs of necrotizing enterocolitis (NEC). We assessed the ability of near-infrared spectroscopy (NIRS) to distinguish those neonates with NEC soon after the occurrence of these symptoms. Study Design We prospectively collected NIRS measurements of abdominal and cerebral regional tissue oxygen saturation (r-SO2), with values masked by an opaque cover. Two physicians, blinded to the NIRS data, determined whether the gastrointestinal symptoms were related to NEC 10 days after symptom onset. Results Forty-five neonates with mean (standard deviation [SD]) gestational, birth weight and postnatal ages of 31 (3.9) weeks, 1,486 (794) g, and 18 (14) days were enrolled over 30 months. Gastrointestinal symptoms were related to NEC in 23 patients and associated with other causes in 22. Analysis of the 48 hours of monitoring revealed comparable abdominal r-SO2 and splanchnic-cerebral oxygenation ratio (SCOR) in patients with and without NEC (r-SO2: 47.3 [20.4] vs. 50.4 [17.8], p = 0.59, SCOR: 0.64 [0.26] vs. 0.69 [0.24], p = 0.51). Results were unchanged after NIRS analysis in 6-hour periods, and restriction of the analysis to severe NEC (i.e., grade 2 and 3, 57% of the NEC cases). Conclusion In this study, NIRS monitoring was unable to individualize NEC in premature infants with acute gastrointestinal symptoms.

scholarly journals Using a Portable Near-infrared Spectroscopy Device to Estimate The Second Ventilatory Threshold

2021 ◽  
Author(s):  
Víctor Rodrigo-Carranza ◽  
Fernando González-Mohíno ◽  
Anthony P. Turner ◽  
Sergio Rodriguez-Barbero ◽  
José María González-Ravé
Keyword(s):  
Infrared Spectroscopy ◽  
Gas Exchange ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Ventilatory Threshold ◽  
Maximum Heart Rate ◽  
Nirs Data ◽  
Trained Runners ◽  
Healthy Participants

AbstractA breakpoint in a portable near-infrared spectroscopy (NIRS) derived deoxygenated haemoglobin (deoxy[Hb]) signal during an incremental VO2max running test has been associated with the second ventilatory threshold (VT2) in healthy participants. Thus, the aim was to examine the association between this breakpoint (NIRS) and VT2 in well-trained runners. Gas exchange and NIRS data were collected during an incremental VO2max running test for 10 well-trained runners. The breakpoint calculated in oxygen saturation (StO2) and the VT2 were determined and compared in terms relative to %VO2max, absolute speed, VO2, and maximum heart rate (HRmax). There were no significant differences (p>0.05) between the breakpoint in StO2 and VT2 relative to %VO2max (87.00±6.14 and 88.28 ± 3.98 %), absolute speed (15.70±1.42 and 16.10±1.66 km·h−1), VO2 (53.71±15.17 and 54.66±15.57 ml·kg−1·min−1), and%HRmax (90.90±4.17 and 91.84±3.70%). There were large and significant correlations between instruments relative to%VO2max (r=0.68, p<0.05), absolute speed (r=0.86, p<0.001), VO2 (r=0.86, p<0.001), and %HRmax (r=0.69; p<0.05). A Bland and Altman analysis of agreement between instruments resulted in a mean difference of − 1.27±4.49%, −0.40±0.84 km·h−1,−0.90±3.07 ml·kg−1·min−1, and − 0.94±3.14 for %VO2max, absolute speed, VO2, and %HRmax, respectively. We conclude that a portable NIRS determination of the StO2 breakpoint is comparable with VT2 using gas exchange and therefore appropriate for use in determining exercise training above VT2 intensity. This is the first study to analyze the validity with the running mode using a NIRS portable device.

scholarly journals Development of the hyperspectral near infrared spectroscopy for monitoring tissue oxygen metabolism

2021 ◽  
Author(s):  
Reyhaneh Nosrati
Keyword(s):  
Signal Processing ◽  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Oxygen Metabolism ◽  
Processing Algorithm ◽  
Mathematical Concepts ◽  
Signal Processing Algorithm ◽  
Nirs Data ◽  
Series Of Experiments

Near Infrared Spectroscopy (NIRS) employs optical window of 650-1100 nm to measure the concentrations of different chromophores such as, oxygenated hemoglobin (HbO2), deoxygenated hemoglobin (Hb) and water. In addition, changes in the redox cytochrome c oxidase (Cyt-ox) can be measured using hyperspectral NIRS. Cyt-ox has a relatively low concentration compared to HbO2 and HHb therefore its measurements is very challenging. The main objective of this thesis was to identify the best signal-processing algorithm for deconvolution of the Cyt-ox changes. In this thesis two different studies have been done; in the first study, functional broadband NIRS during simulated driving (on 16 adult subjects) has been recorded and the best data processing algorithm for deconvolution of the chromophores was identified. In the second series of experiments broadband NIRS data during cardiac arrest and resuscitation was recorded on 19 pigs. A novel signal-processing algorithm was introduced to deconvolve Cyt-ox. The Introduction section covers relevant aspects of the theory and mathematical concepts. The Journal Manuscript part contains the two projects mentioned above. The last part is The Journal Manuscript part contains the two projects mentioned above. The last part is allocated for the overall conclusion of the entire thesis.

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