Processing of laser-Doppler signals from free flaps

Söderström, Torsten; Svensson, Henry; Koop, T.; Möller, K. O.

doi:10.3233/thc-1999-72-312

Cited by 10 publications

(10 citation statements)

References 5 publications

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“…To the best of our knowledge, this is the first study that decomposed LDF signals by the WT to gain insight into the physiological mechanisms underlying the effect of an OGL on cutaneous microcirculation. All LDF spectra revealed five main frequency components [36]-cardiac [33], respiratory [37], myogenic (i.e., vasomotion) [38], sympathetic [39], and endothelial activity, the latter being subdivided into NOd and NOi [36]. These components showed no significant frequency shifts (i.e., no shifts of the frequency corresponding to the maximal amplitude; data not shown) with either glucose or water load in either pre-load or post-load periods.…”

Section: Discussionmentioning

confidence: 90%

Oral Glucose Load and Human Cutaneous Microcirculation: An Insight into Flowmotion Assessed by Wavelet Transform

Silva

Šorli

Lenasi

2021

Biology

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Microcirculation in vivo has been assessed using non-invasive technologies such as laser Doppler flowmetry (LDF). In contrast to chronic hyperglycemia, known to induce microvascular dysfunction, the effects of short-term elevations in blood glucose on microcirculation are controversial. We aimed to assess the impact of an oral glucose load (OGL) on the cutaneous microcirculation of healthy subjects, quantified by LDF and coupled with wavelet transform (WT) as an interpretation tool. On two separate occasions, sixteen subjects drank either a glucose solution (75 g in 250 mL water) or water (equal volume). LDF signals were obtained in two anatomical sites (forearm and finger pulp) before and after each load (pre-load and post-load, respectively), in resting conditions and during post-occlusive reactive hyperemia (PORH). The WT allowed decomposition of the LDF signals into their spectral components (cardiac, respiratory, myogenic, sympathetic, endothelial NO-dependent). The OGL blunted the PORH response in the forearm, which was not observed with the water load. Significant differences were found for the cardiac and sympathetic components in the glucose and water groups between the pre-load and post-load periods. These results suggest that an OGL induces a short-term subtle microvascular impairment, probably involving a modulation of the sympathetic nervous system.

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Section: Discussionmentioning

confidence: 90%

Oral Glucose Load and Human Cutaneous Microcirculation: An Insight into Flowmotion Assessed by Wavelet Transform

Silva

Šorli

Lenasi

2021

Biology

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“…In order to look deeper into LDF and PPG flowmotion, we analyzed changes occurring under challenge by the wavelet transform (WT), a well-known analytical instrument mostly applied to LDF analysis refinement. For LDF it is accepted that those oscillations, cardiac (0.6–2.0 Hz), respiration (0.15–0.6 Hz), myogenic (∼0.05–0.15 Hz), neurogenic (∼0.02–0.05 Hz), and endothelial (∼0.0095–0.02 Hz), determining skin flowmotion, represent the influence of heart rate, respiration, myogenic 36,42 , autonomical 39,45 , and endothelial dependent and independent vascular smooth muscle relaxation 35,40,46 .…”

Section: Discussionmentioning

confidence: 99%

Different lasers reveal different skin microcirculatory flowmotion - data from the wavelet transform analysis of human hindlimb perfusion

Rodrigues

Rocha

Ferreira

et al. 2019

Sci Rep

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Laser Doppler flowmetry (LDF) and reflection photoplethysmography (PPG) are standard technologies to access microcirculatory function in vivo. However, different light frequencies mean different interaction with tissues, such that LDF and PPG flowmotion curves might have distinct meanings, particularly during adaptative (homeostatic) processes. Therefore, we analyzed LDF and PPG perfusion signals obtained in response to opposite challenges. Young healthy volunteers, both sexes, were assigned to Group 1 (n = 29), submitted to a normalized Swedish massage procedure in one lower limb, increasing perfusion, or Group 2 (n = 14), submitted to a hyperoxia challenge test, decreasing perfusion. LDF (Periflux 5000) and PPG (PLUX-Biosignals) green light sensors applied distally on both lower limbs recorded perfusion changes for each experimental protocol. Both techniques detected the perfusion increase with massage, and the perfusion decrease with hyperoxia, in both limbs. Further analysis with the wavelet transform (WT) revealed better depth-related discriminative ability for PPG (more superficial, less blood sampling) compared with LDF in both challenges. Spectral amplitude profiles consistently demonstrated better sensitivity for LDF, especially regarding the lowest frequency components. Strong correlations between components were not found. Therefore, LDF and PPG flowmotion curves are not equivalent, a relevant finding to better study microcirculatory physiology.

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“…The analytical processing of laser Doppler flowmetry signals can give valuable information. Frequency, signal averaging, and waveform analyses 8,9 can help, for example, to measure differences between arterial and venous congestion, to process vasomotion, to estimate the capillary state, or even to explore the ''no-reflow'' areas. 2,10 During examinations, it is essential to obtain a stable measurement, minimizing the artifacts in the recorded signal data due to, for example, muscle and respiratory movements.…”

Section: Discussionmentioning

confidence: 99%

Changes in microcirculation after ischemic process in rat skeletal muscle

Németh¹,

Lesznyák²,

Bráth³

et al. 2003

Microsurgery

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Laser Doppler flowmetry (LDF) is a good method to investigate tissue microcirculation, but it has many standardization and measuring problems. To exclude these effects, we performed a test using LDF on rat skeletal muscle. In 12 CD outbred anesthetized rats, bilateral femoral vessels and the quadriceps femoris muscle were exposed. The left femoral artery and vein were clamped for 1 h by microvascular clips (ischemic side). On the right side, no other intervention was made (control side). An LDF probe was applied on the medial vastus muscle. Short-term occlusions (2-3 s) were performed before and after the 1-h clamping and on the control side while LDF curves were registered. The halftimes of ascending curves on the ischemic side were significantly elongated vs. the condition before clamping (P = 0.0007) or the control side (P = 0.0017). Microcirculatory changes caused by 1-h ischemia were shown by this simple, quick, and well-reproducible test on rat skeletal muscle.

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Processing of laser-Doppler signals from free flaps

Cited by 10 publications

References 5 publications

Oral Glucose Load and Human Cutaneous Microcirculation: An Insight into Flowmotion Assessed by Wavelet Transform

Oral Glucose Load and Human Cutaneous Microcirculation: An Insight into Flowmotion Assessed by Wavelet Transform

Different lasers reveal different skin microcirculatory flowmotion - data from the wavelet transform analysis of human hindlimb perfusion

Changes in microcirculation after ischemic process in rat skeletal muscle

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