Near Infrared Optical Monitoring of Intact Skeletal Muscle During Hypoxia and Hemorrhagic Hypotension in Cats

1985 ◽  
pp. 855-862 ◽  
Author(s):  
C. A. Piantadosi ◽  
F. F. Jöbsis-Vander Vliet
Keyword(s):  
Skeletal Muscle ◽  
Near Infrared ◽  
Optical Monitoring ◽  
Hemorrhagic Hypotension

A comparison of exercise type and intensity on the noninvasive assessment of skeletal muscle mitochondrial function using near-infrared spectroscopy

2013 ◽  
Vol 114 (2) ◽  
pp. 230-237 ◽  
Author(s):  
Terence E. Ryan ◽  
Jared T. Brizendine ◽  
Kevin K. McCully
Keyword(s):  
Skeletal Muscle ◽  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Mitochondrial Function ◽  
Rate Constants ◽  
Near Infrared ◽  
Clinical Settings ◽  
Muscle Oxygen ◽  
Muscle Oxygen Consumption ◽  
Intensity Of Exercise

Near-infrared spectroscopy (NIRS) can be used to measure muscle oxygen consumption (mVO2) using arterial occlusions. The recovery rate of mVO2after exercise can provide an index of skeletal muscle mitochondrial function. The purpose of this study was to test the influence of exercise modality and intensity on NIRS measurements of mitochondrial function. Three experiments were performed. Thirty subjects (age: 18–27 yr) were tested. NIRS signals were corrected for blood volume changes. The recovery of mVO2after exercise was fit to a monoexponential curve, and a rate constant was calculated (directly related to mitochondrial function). No differences were found in NIRS rate constants for VOL and ES exercises (2.04 ± 0.57 vs. 2.01 ± 0.59 min−1for VOL and ES, respectively; P = 0.317). NIRS rate constants were independent of the contraction frequency for both VOL and ES (VOL: P = 0.166 and ES: P = 0.780). ES current intensity resulted in significant changes to the normalized time-tension integral (54 ± 11, 82 ± 7, and 100 ± 0% for low, medium, and high currents, respectively; P < 0.001) but did not influence NIRS rate constants (2.02 ± 0.54, 1.95 ± 0.44, 2.02 ± 0.46 min−1for low, medium, and high currents, respectively; P = 0.771). In summary, NIRS measurements of skeletal muscle mitochondrial function can be compared between VOL and ES exercises and were independent of the intensity of exercise. NIRS represents an important new technique that is practical for testing in research and clinical settings.

Oxygen delivery-utilization mismatch in contracting locomotor muscle in COPD: peripheral factors

2015 ◽  
Vol 308 (2) ◽  
pp. R105-R111 ◽  
Author(s):  
Wladimir M. Medeiros ◽  
Mari C. T. Fernandes ◽  
Diogo P. Azevedo ◽  
Flavia F. M. de Freitas ◽  
Beatriz C. Amorim ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Mass ◽  
Near Infrared ◽  
Neuromuscular Electrical Stimulation ◽  
Muscle Oxygenation ◽  
Whole Body ◽  
Chronic Obstructive ◽  
Copd Patients ◽  
Skeletal Muscle Oxygenation ◽  
Severe Copd

Central cardiorespiratory and gas exchange limitations imposed by chronic obstructive pulmonary disease (COPD) impair ambulatory skeletal muscle oxygenation during whole body exercise. This investigation tested the hypothesis that peripheral factors per se contribute to impaired contracting lower limb muscle oxygenation in COPD patients. Submaximal neuromuscular electrical stimulation (NMES; 30, 40, and 50 mA at 50 Hz) of the quadriceps femoris was employed to evaluate contracting skeletal muscle oxygenation while minimizing the influence of COPD-related central cardiorespiratory constraints. Fractional O2 extraction was estimated by near-infrared spectroscopy (deoxyhemoglobin/myoglobin concentration; deoxy-[Hb/Mb]), and torque output was measured by isokinetic dynamometry in 15 nonhypoxemic patients with moderate-to-severe COPD (SpO2 = 94 ± 2%; FEV1 = 46.4 ± 10.1%; GOLD II and III) and in 10 age- and gender-matched sedentary controls. COPD patients had lower leg muscle mass than controls (LMM = 8.0 ± 0.7 kg vs. 8.9 ± 1.0 kg, respectively; P < 0.05) and produced relatively lower absolute and LMM-normalized torque across the range of NMES intensities ( P < 0.05 for all). Despite producing less torque, COPD patients had similar deoxy-[Hb/Mb] amplitudes at 30 and 40 mA ( P > 0.05 for both) and higher deoxy-[Hb/Mb] amplitude at 50 mA ( P < 0.05). Further analysis indicated that COPD patients required greater fractional O2 extraction to produce torque (i.e., ↑Δdeoxy-[Hb/Mb]/torque) relative to controls ( P < 0.05 for 40 and 50 mA) and as a function of NMES intensity ( P < 0.05 for all). The present data obtained during submaximal NMES of small muscle mass indicate that peripheral abnormalities contribute mechanistically to impaired contracting skeletal muscle oxygenation in nonhypoxemic, moderate-to-severe COPD patients.

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.

Abstract 2769: Impaired Skeletal Muscle Oxygen Utilization Contributes to Exercise Intolerance in Barth Syndrome

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Carolyn T Spencer ◽  
Randall M Bryant ◽  
Barry Byrne ◽  
Elisabeth Heal ◽  
Renee Margossian ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Cardiac Function ◽  
Mitochondrial Dysfunction ◽  
Near Infrared ◽  
Vastus Lateralis ◽  
Barth Syndrome ◽  
Exercise Intolerance ◽  
Peak Exercise ◽  
Indirect Measure ◽  
Muscle Oxygen

Objective s: Barth Syndrome (BTHS) is an X-linked mutation in the TAZ gene characterized by cardiolipin deficiency, mitochondrial dysfunction and cardio-skeletal myopathy. We hypothe- sized that abnormal skeletal muscle oxygen (O 2 ) utilization contributes to exercise intolerance in BTHS. Methods : Boys with BTHS (n=13) and healthy male controls (n=7) performed a graded exercise test on a cycle ergometer with continuous metabolic and EKG monitoring. Near infrared spectroscopy (NIRS), an indirect measure of tissue O 2 saturation and index of skeletal muscle O 2 utilization, was applied to the vastus lateralis during exercise. Cardiac function in BTHS was assessed by echocardiography and serum BNP to examine the relationship between resting cardiac function and exercise capacity in BTHS. Results : Age (16±5 vs 13±3 years; p=0.22), BMI (17±3 vs. 20±5; p=0.14) and BSA (1.0±0.5 vs 1.2±0.6 m 2 ; p=0.3) were not different between BTHS and controls. BTHS had lower peak VO 2 (19±6 vs. 52±6 ml/kg/min, p < 0.001), lower % of predicted peak VO 2 (40±10% vs. 115±12%, p=0.0004), lower peak work rate (58±18 vs. 205±69 watts, p=0.0004), and lower peak O 2 pulse (4.6±1.6 vs. 14±6 ml O 2 /kg/beat, p< 0.00001) than controls. Peak HR in BTHS was lower but remained within normal peak predicted rate (172±14 vs. 197±11 bpm, p=0.001). Vastus lateralis tissue O 2 saturation at peak exercise decreased from baseline in controls as expected (-18±16%, p<0.001) but paradoxically increased from baseline in BTHS (+17±14%, p<0.03, p=0.0005 BTHS vs. controls) indicating impaired muscle O 2 utilization. Absolute (r= - 0.70, p<0.0001) and percent (r= - 0.70, p<0.001) change in NIRS from baseline was negatively associated with peak VO 2 . There was no correlation between peak VO 2 and resting EF (55±7%; r=0.12), SF (30±4%; r= -.26), myocardial performance index (0.4±0.1; r= -.3) or serum BNP (232±381; r=0.1). Conclusion : O 2 consumption during exercise in BTHS is severely reduced and caused, at least in part, by impaired skeletal muscle O 2 utilization. Resting cardiac function is not related to O 2 consumption in BTHS but cardiac dysfunction during exercise in BTHS is not excluded without further studies. Mitochondrial dysfunction likely mediates skeletal muscle O 2 utilization deficits during exercise in BTHS.

Sign in / Sign up

Export Citation Format

Share Document