Quantifying low-frequency fluctuations in the laser Doppler flow signal from human skin

2011 ◽  
Author(s):  
M. S. Folgosi-Correa ◽  
G. E. C. Nogueira
Keyword(s):  
Human Skin ◽  
Low Frequency ◽  
Laser Doppler ◽  
Laser Doppler Flow ◽  
Doppler Flow ◽  
Flow Signal ◽  
Frequency Fluctuations

scholarly journals Noninvasive Measure of Microvascular Nitric Oxide Function in Humans Using Very Low-Frequency Cutaneous Laser Doppler Flow Spectra

2007 ◽  
Vol 14 (3) ◽  
pp. 169-180 ◽  
Author(s):  
Julian M. Stewart ◽  
Indu Taneja ◽  
Michael S. Goligorsky ◽  
Marvin S. Medow
Keyword(s):  
Nitric Oxide ◽  
Low Frequency ◽  
Laser Doppler ◽  
Laser Doppler Flow ◽  
Doppler Flow ◽  
Very Low Frequency

Synchronous Rhythmical Vasomotion in the Human Cutaneous Microvasculature during Nonpulsatile Cardiopulmonary Bypass

2002 ◽  
Vol 97 (5) ◽  
pp. 1110-1117 ◽  
Author(s):  
Mihai V. Podgoreanu ◽  
Robert G. Stout ◽  
Habib E. El-Moalem ◽  
David G. Silverman
Keyword(s):  
Cardiopulmonary Bypass ◽  
High Frequency ◽  
Spectral Power ◽  
Low Frequency ◽  
Approximate Entropy ◽  
Laser Doppler ◽  
Control Mechanisms ◽  
Laser Doppler Flow ◽  
Doppler Flow ◽  
Normalized Units

Background The origin, control mechanisms, and functional significance of oscillations in microvascular flow are incompletely understood. Although the traditional belief has been that only low-frequency oscillations (0.04-0.10 Hz) can originate at the microvascular level, recent evidence in healthy volunteers has suggested that high-frequency oscillations (> 0.10 Hz) also may have a microvascular origin (as opposed to being mechanically transmitted respiratory-induced variations in stroke volume). The current study determined if such oscillations would emerge in the absence of cardiac and respiratory activity during nonpulsatile cardiopulmonary bypass (NP-CPB). Methods Forehead and finger laser Doppler flow, arterial pressure, and core temperature were simultaneously recorded in eight patients during NP-CPB. Analyses included time- domain indices, frequency-domain indices (auto power spectral density), and a measure of regularity (approximate entropy) for standardized time segments. Results Nonpulsatile cardiopulmonary bypass was associated with the emergence of rhythmical oscillations in laser Doppler flow, with characteristic frequencies for the forehead (0.13 +/- 0.03 Hz) and finger (0.07 +/- 0.02 Hz). Forehead vasomotion became progressively synchronized, with a gain in high-frequency spectral power from 17.5 (minute 1) to 89.1 (minute 40) normalized units, and a decrease in approximate entropy from 1.2 (before NP-CPB) to less than 0.5 (minute 40). Conclusions The emergence of forehead microvascular oscillations at greater than 0.10 Hz (characteristic of parasympathetic frequency response), in the absence of cardiac and respiratory variability, demonstrates their peripheral origin and provides insights into parasympathetic vasoregulatory mechanisms. The progressive synchronization of forehead vasomotion during NP-CPB, suggestive of increased coupling among microvascular biologic oscillators, may represent a microcirculatory homeostatic response to systemic depulsation, with potential implications for end-organ perfusion.

Interpretation of the Laser Doppler Flow Signal from the Liver of the Rat

1993 ◽  
Vol 45 (3) ◽  
pp. 290-301 ◽  
Author(s):  
Anthony M. Wheatley ◽  
Nicholas E. Almond ◽  
Edward T. Stuart ◽  
Delai Zhao
Keyword(s):  
Laser Doppler ◽  
Laser Doppler Flow ◽  
Doppler Flow ◽  
Flow Signal

scholarly journals Noninvasive measure of microvascular nitric oxide function in humans using Very low frequency cutaneous laser Doppler flow spectra.

2007 ◽  
Vol 21 (6) ◽  
Author(s):  
Julian Mark Stewart ◽  
Indu Taneja ◽  
Marvin Scott Medow ◽  
Michael Goligorsky
Keyword(s):  
Nitric Oxide ◽  
Low Frequency ◽  
Laser Doppler ◽  
Laser Doppler Flow ◽  
Doppler Flow ◽  
Very Low Frequency

Laser Doppler Flow-Meter Assessment of Iontophoretically Applied Norepinephrine on Human Finger Skin Circulation

1986 ◽  
Vol 87 (5) ◽  
pp. 634-636 ◽  
Author(s):  
Lars Erik Lindblad ◽  
Lena Ekenvall ◽  
Klas Ancker ◽  
Håkan Rohman ◽  
P Åke Öberg
Keyword(s):  
Laser Doppler ◽  
Flow Meter ◽  
Laser Doppler Flow ◽  
Doppler Flow ◽  
Skin Circulation ◽  
Human Finger ◽  
Finger Skin

Increased laser Doppler flow in skin tumors corresponds to elevated vessel density and reactive hyperemia

2006 ◽  
Vol 12 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Markus Stucker ◽  
Christian Springer ◽  
Volker Paech ◽  
Nico Hermes ◽  
Matthias Hoffmann ◽  
...  
Keyword(s):  
Reactive Hyperemia ◽  
Skin Tumors ◽  
Vessel Density ◽  
Laser Doppler ◽  
Laser Doppler Flow ◽  
Doppler Flow
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