Noninvasive assessment of sympathetic vasoconstriction in human and rodent skeletal muscle using near-infrared spectroscopy and Doppler ultrasound

2004 ◽  
Vol 96 (4) ◽  
pp. 1323-1330 ◽  
Author(s):  
Paul J. Fadel ◽  
David M. Keller ◽  
Hitoshi Watanabe ◽  
Peter B. Raven ◽  
Gail D. Thomas
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Doppler Ultrasound ◽  
Near Infrared ◽  
Tissue Oxygenation ◽  
Nir Spectroscopy ◽  
Sympathetic Nerves ◽  
Sympathetic Activation ◽  
Sympathetic Vasoconstriction ◽  
Highly Correlated

The precise role of the sympathetic nervous system in the regulation of skeletal muscle blood flow during exercise has been challenging to define in humans, partly because of the limited techniques available for measuring blood flow in active muscle. Recent studies using near-infrared (NIR) spectroscopy to measure changes in tissue oxygenation have provided an alternative method to evaluate vasomotor responses in exercising muscle, but this approach has not been fully validated. In this study, we tested the hypothesis that sympathetic activation would evoke parallel changes in tissue oxygenation and blood flow in resting and exercising muscle. We simultaneously measured tissue oxygenation with NIR spectroscopy and blood flow with Doppler ultrasound in skeletal muscle of conscious humans ( n = 13) and anesthetized rats ( n = 9). In resting forearm of humans, reflex activation of sympathetic nerves with the use of lower body negative pressure produced graded decreases in tissue oxygenation and blood flow that were highly correlated ( r = 0.80, P < 0.0001). Similarly, in resting hindlimb of rats, electrical stimulation of sympathetic nerves produced graded decreases in tissue oxygenation and blood flow velocity that were highly correlated ( r = 0.93, P < 0.0001). During rhythmic muscle contraction, the decreases in tissue oxygenation and blood flow evoked by sympathetic activation were significantly attenuated ( P < 0.05 vs. rest) but remained highly correlated in both humans ( r = 0.80, P < 0.006) and rats ( r = 0.92, P < 0.0001). These data indicate that, during steady-state metabolic conditions, changes in tissue oxygenation can be used to reliably assess sympathetic vasoconstriction in both resting and exercising skeletal muscle.

Tissue Oxygenation by Near-Infrared Spectroscopy and Muscle Blood Flow During Isometric Contractions of the Forearm

1999 ◽  
Vol 24 (3) ◽  
pp. 216-230 ◽  
Author(s):  
Andrew Hicks ◽  
Stuart Mcgill ◽  
Richard L. Hughson
Keyword(s):  
Blood Flow ◽  
Infrared Spectroscopy ◽  
Doppler Ultrasound ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Tissue Oxygenation ◽  
Muscle Blood Flow ◽  
Venous Blood ◽  
Muscle Oxygenation ◽  
Isometric Contractions

The relationship between tissue oxygenation measured by near-infrared spectroscopy (NIRS) and forearm muscle blood flow (FBF) measured by Doppler ultrasound was tested during isometric contractions at 10 and 30% maximal voluntary contraction (MVC) under conditions of normoxia and hypoxia (14% inspired O2). Six subjects maintained contractions at 10% MVCfor 5 min and at 30% for 2 min in both gas conditions. FBF was elevated during exercise at 10% MVC in hypoxia compared to normoxia, but there was no further increase in flow at 30% MVC. Median power frequency calculations from electromyographic recordings suggested progressive development of fatigue throughout both 10 and 30% MVC contractions. NIRS indicated no change in muscle oxygenation at 10% MVC, but deep venous blood O2 saturation was reduced in normoxia and more so in hypoxia. At 30% MVC, both NIRS and venous O2 saturation were reduced, with no effect of hypoxia on the NIRS signal. While NIRS might provide an indication of muscle oxygenation during isometric exercise, the conflicting findings for NIRS and direct venous blood sampling at 10 vs. 30% MVC suggest caution in the application of this noninvasive technique. Key words: exercise, Doppler ultrasound, venous blood. O2 saturation, hemoglobin

Light source-detector spacing of near-infrared-based tissue oximeters and the influence of skin blood flow

2006 ◽  
Vol 100 (4) ◽  
pp. 1426-1427 ◽  
Author(s):  
Marco Ferrari ◽  
Valentina Cettolo ◽  
Valentina Quaresima
Keyword(s):  
Blood Flow ◽  
Skin Blood Flow ◽  
Near Infrared ◽  
Tissue Oxygenation ◽  
Local Heating ◽  
Muscle Blood Flow ◽  
Nir Spectroscopy ◽  
Whole Body ◽  
Blood Flows ◽  
Measurable Change

Near-infrared (NIR) spectroscopy is a noninvasive optical technique that is increasingly used to assess muscle oxygenation during exercise with the assumption that the contribution of skin blood flow to the NIR signal is minor or nonexistent. We tested this assumption in humans by monitoring forearm tissue oxygenation during selective cutaneous vasodilation induced by locally applied heat ( n = 6) or indirect whole body heating (i.e., heating subject but not area surrounding NIR probes; n = 8). Neither perturbation has been shown to cause a measurable change in muscle blood flow or metabolism. Local heating (∼41°C) caused large increases in the NIR-derived tissue oxygenation signal [before heating = 0.82 ± 0.89 optical density (OD), after heating = 18.21 ± 2.44 OD; P < 0.001]. Similarly, whole body heating (increase internal temperature 0.9°C) also caused large increases in the tissue oxygenation signal (before heating = −0.31 ± 1.47 OD, after heating = 12.48 ± 1.82 OD; P < 0.001). These increases in the tissue oxygenation signal were closely correlated with increases in skin blood flow during both local heating (mean r = 0.95 ± 0.02) and whole body heating (mean r = 0.89 ± 0.04). These data suggest that the contribution of skin blood flow to NIR measurements of tissue oxygenation can be significant, potentially confounding interpretation of the NIR-derived signal during conditions where both skin and muscle blood flows are elevated concomitantly (e.g., high-intensity and/or prolonged exercise).

scholarly journals Dynamic exercise attenuates sympathetic responsiveness of canine vascular smooth muscle

2000 ◽  
Vol 89 (6) ◽  
pp. 2294-2299 ◽  
Author(s):  
Stephen B. Ruble ◽  
Zoran Valic ◽  
John B. Buckwalter ◽  
Philip S. Clifford
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Treadmill Exercise ◽  
Sympathetic Nerves ◽  
Dynamic Exercise ◽  
Intravenous Bolus ◽  
Sympathetic Activation ◽  
Vascular Effects ◽  
Vascular Conductance ◽  
Iliac Arteries

The phenomenon of reduced responsiveness of the skeletal muscle arterial vasculature to sympathetic activation during exercise (sympatholysis) remains controversial. The purpose of this study was to examine the vascular effects of sympathoactivation in dynamically exercising skeletal muscle. Mongrel dogs (19–24 kg) were instrumented chronically with transit-time ultrasonic flow probes on the external iliac arteries. After pretreatment with atropine (0.2 mg/kg), an intravenous bolus (4 μg/kg) of a nicotinic ganglion stimulant [1,1-dimethyl-4-phenylpiperazinium iodide (DMPP)] was given at rest and during treadmill exercise at graded intensities. Administration of DMPP was associated with prompt reductions in iliac blood flow and increases in arterial pressure under all conditions. There were significant reductions ( P < 0.05) in iliac vascular conductance of 58 ± 4 (SE), 48 ± 3, 36 ± 5, and 16 ± 3% at rest, 3 miles/h and 0% grade, 6 miles/h and 0% grade, and 6 miles/h and 15% grade, respectively. These data demonstrate that activation of postganglionic sympathetic nerves with DMPP caused vasoconstriction in the skeletal muscle vasculature at rest and during exercise. Additionally, the magnitude of vasoconstriction was inversely related to exercise intensity. These results support the concept of exercise sympatholysis.

Skin blood flow influences near-infrared spectroscopy-derived measurements of tissue oxygenation during heat stress

2006 ◽  
Vol 100 (1) ◽  
pp. 221-224 ◽  
Author(s):  
Scott L. Davis ◽  
Paul J. Fadel ◽  
Jian Cui ◽  
Gail D. Thomas ◽  
Craig G. Crandall
Keyword(s):  
Blood Flow ◽  
Skin Blood Flow ◽  
Near Infrared ◽  
Tissue Oxygenation ◽  
Local Heating ◽  
Muscle Blood Flow ◽  
Nir Spectroscopy ◽  
Whole Body ◽  
Blood Flows ◽  
Measurable Change

Near-infrared (NIR) spectroscopy is a noninvasive optical technique that is increasingly used to assess muscle oxygenation during exercise with the assumption that the contribution of skin blood flow to the NIR signal is minor or nonexistent. We tested this assumption in humans by monitoring forearm tissue oxygenation during selective cutaneous vasodilation induced by locally applied heat ( n = 6) or indirect whole body heating (i.e., heating subject but not area surrounding NIR probes; n = 8). Neither perturbation has been shown to cause a measurable change in muscle blood flow or metabolism. Local heating (∼41°C) caused large increases in the NIR-derived tissue oxygenation signal [before heating = 0.82 ± 0.89 optical density (OD), after heating = 18.21 ± 2.44 OD; P < 0.001]. Similarly, whole body heating (increase internal temperature 0.9°C) also caused large increases in the tissue oxygenation signal (before heating = −0.31 ± 1.47 OD, after heating = 12.48 ± 1.82 OD; P < 0.001). These increases in the tissue oxygenation signal were closely correlated with increases in skin blood flow during both local heating (mean r = 0.95 ± 0.02) and whole body heating (mean r = 0.89 ± 0.04). These data suggest that the contribution of skin blood flow to NIR measurements of tissue oxygenation can be significant, potentially confounding interpretation of the NIR-derived signal during conditions where both skin and muscle blood flows are elevated concomitantly (e.g., high-intensity and/or prolonged exercise).

scholarly journals Increased tissue oxygenation explains the attenuation of hyperemia upon repetitive pneumatic compression of the lower leg

2017 ◽  
Vol 123 (6) ◽  
pp. 1451-1460 ◽  
Author(s):  
Alessandro Messere ◽  
Gianluca Ceravolo ◽  
Walter Franco ◽  
Daniela Maffiodo ◽  
Carlo Ferraresi ◽  
...  
Keyword(s):  
Blood Flow ◽  
Blood Volume ◽  
Near Infrared ◽  
Tissue Oxygenation ◽  
Femoral Vein ◽  
Lower Leg ◽  
Local Circulation ◽  
Doppler Measurement ◽  
Key Factor ◽  
Interstimulus Intervals

The rapid hyperemia evoked by muscle compression is short lived and was recently shown to undergo a rapid decrease even in spite of continuing mechanical stimulation. The present study aims at investigating the mechanisms underlying this attenuation, which include local metabolic mechanisms, desensitization of mechanosensitive pathways, and reduced efficacy of the muscle pump. In 10 healthy subjects, short sequences of mechanical compressions ( n = 3–6; 150 mmHg) of the lower leg were delivered at different interstimulus intervals (ranging from 20 to 160 s) through a customized pneumatic device. Hemodynamic monitoring included near-infrared spectroscopy, detecting tissue oxygenation and blood volume in calf muscles, and simultaneous echo-Doppler measurement of arterial (superficial femoral artery) and venous (femoral vein) blood flow. The results indicate that 1) a long-lasting (>100 s) increase in local tissue oxygenation follows compression-induced hyperemia, 2) compression-induced hyperemia exhibits different patterns of attenuation depending on the interstimulus interval, 3) the amplitude of the hyperemia is not correlated with the amount of blood volume displaced by the compression, and 4) the extent of attenuation negatively correlates with tissue oxygenation ( r = −0,78, P < 0.05). Increased tissue oxygenation appears to be the key factor for the attenuation of hyperemia upon repetitive compressive stimulation. Tissue oxygenation monitoring is suggested as a useful integration in medical treatments aimed at improving local circulation by repetitive tissue compression. NEW & NOTEWORTHY This study shows that 1) the hyperemia induced by muscle compression produces a long-lasting increase in tissue oxygenation, 2) the hyperemia produced by subsequent muscle compressions exhibits different patterns of attenuation at different interstimulus intervals, and 3) the extent of attenuation of the compression-induced hyperemia is proportional to the level of oxygenation achieved in the tissue. The results support the concept that tissue oxygenation is a key variable in blood flow regulation.

Impact of Changes in Tissue Optical Properties on Near-Infrared Diffuse Correlation Spectroscopy Measures of Skeletal Muscle Blood Flow

2021 ◽  
Author(s):  
Miles F. Bartlett ◽  
Scott M. Jordan ◽  
Dennis M. Hueber ◽  
Michael D. Nelson
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Optical Properties ◽  
Near Infrared ◽  
Muscle Blood Flow ◽  
Reactive Hyperemia ◽  
Correlation Spectroscopy ◽  
Skeletal Muscle Blood Flow ◽  
Diffuse Correlation Spectroscopy ◽  
Tissue Optical Properties

Near-infrared diffuse correlation spectroscopy (DCS) is increasingly utilized to study relative changes in skeletal muscle blood flow. However, most diffuse correlation spectrometers assume that tissue optical properties- such as absorption (μa) and reduced scattering (μ's) coefficients- remain constant during physiological provocations, which is untrue for skeletal muscle. Here, we interrogate how changes in tissue μa and μ's affect DCS calculations of blood flow index (BFI). We recalculated BFI using raw autocorrelation curves and μa/μ's values recorded during a reactive hyperemia protocol in 16 healthy young individuals. First, we show that incorrectly assuming baseline μa and μ's substantially affects peak BFI and BFI slope when expressed in absolute terms (cm2/s, p<0.01) but these differences are abolished when expressed in relative terms (% baseline). Next, to evaluate the impact of physiologic changes in μa and μ's, we compared peak BFI and BFI slope when μa and μ's were held constant throughout the reactive hyperemia protocol versus integrated from a 3s-rolling average. Regardless of approach, group means for peak BFI and BFI slope did not differ. Group means for peak BFI and BFI slope were also similar following ad absurdum analyses, where we simulated supraphysiologic changes in μa/μ's. In both cases, however, we identified individual cases where peak BFI and BFI slope were indeed affected, with this result being driven by relative changes in μa over μ's. Overall, these results provide support for past reports in which μa/μ's were held constant but also advocate for real-time incorporation of μa and μ's moving forward.

Principles, Techniques, and Limitations of Near Infrared Spectroscopy

2004 ◽  
Vol 29 (4) ◽  
pp. 463-487 ◽  
Author(s):  
Marco Ferrari ◽  
Leonardo Mottola ◽  
Valentina Quaresima
Keyword(s):  
Blood Flow ◽  
Near Infrared ◽  
Dynamic Balance ◽  
Exercise Physiology ◽  
Muscle Blood Flow ◽  
Subcutaneous Fat ◽  
Nir Spectroscopy ◽  
Radical Change ◽  
Cortical Activation ◽  
Muscle Energetics

In the last decade the study of the human brain and muscle energetics underwent a radical change, thanks to the progressive introduction of noninvasive techniques, including near-infrared (NIR) spectroscopy (NIRS). This review summarizes the most recent literature about the principles, techniques, advantages, limitations, and applications of NIRS in exercise physiology and neuroscience. The main NIRS instrumentations and measurable parameters will be reported. NIR light (700-1000 nm) penetrates superficial layers (skin, subcutaneous fat, skull, etc.) and is either absorbed by chromophores (oxy- and deoxyhemoglobin and myoglobin) or scattered within the tissue. NIRS is a noninvasive and relatively low-cost optical technique that is becoming a widely used instrument for measuring tissue O2 saturation, changes in hemoglobin volume and, indirectly, brain/muscle blood flow and muscle O2 consumption. Tissue O2 saturation represents a dynamic balance between O2 supply and O2 consumption in the small vessels such as the capillary, arteriolar, and venular bed. The possibility of measuring the cortical activation in response to different stimuli, and the changes in the cortical cytochrome oxidase redox state upon O2 delivery changes, will also be mentioned. Key words: tissue oximetry, oxidative metabolism, optical imaging, blood flow, oxygen consumption, exercise physiology

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