scholarly journals Body Position Affects Capillary Blood Flow Regulation Measured with Wearable Blood Flow Sensors

Diagnostics ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 436
Author(s):  
Andrey A. Fedorovich ◽  
Yulia I. Loktionova ◽  
Elena V. Zharkikh ◽  
Maria A. Mikhailova ◽  
Julia A. Popova ◽  
...  
Keyword(s):  
Blood Flow ◽  
Laser Doppler Flowmetry ◽  
Body Position ◽  
Blood Perfusion ◽  
The Body ◽  
Laser Doppler ◽  
Doppler Flowmetry ◽  
Postural Changes ◽  
Skin Blood Perfusion ◽  
The Right

In this study we demonstrate what kind of relative alterations can be expected in average perfusion and blood flow oscillations during postural changes being measured in the skin of limbs and on the brow of the forehead by wearable laser Doppler flowmetry (LDF) sensors. The aims of the study were to evaluate the dynamics of cutaneous blood perfusion and the regulatory mechanisms of blood microcirculation in the areas of interest, and evaluate the possible significance of those effects for the diagnostics based on blood perfusion monitoring. The study involved 10 conditionally healthy volunteers (44 ± 12 years). Wearable laser Doppler flowmetry monitors were fixed at six points on the body: two devices were fixed on the forehead, on the brow; two were on the distal thirds of the right and left forearms; and two were on the distal thirds of the right and left lower legs. The protocol was used to record three body positions on the tilt table for orthostatic test for each volunteer in the following sequence: (a) supine body position; (b) upright body position (+75°); (c) tilted with the feet elevated above the head and the inclination of body axis of 15° (−15°, Trendelenburg position). Skin blood perfusion was recorded for 10 min in each body position, followed by the amplitude–frequency analysis of the registered signals using wavelet decomposition. The measurements were supplemented with the blood pressure and heart rate for every body position analysed. The results identified a statistically significant transformation in microcirculation parameters of the average level of skin blood perfusion and oscillations of amplitudes of neurogenic, myogenic and cardiac sensors caused by the postural changes. In paper, we present the analysis of microcirculation in the skin of the forehead, which for the first time was carried out in various positions of the body. The area is supplied by the internal carotid artery system and can be of particular interest for evaluation of the sufficiency of blood supply for the brain.

scholarly journals Nonlinear analysis of fluctuations of microcirculation parameters in symmetrical organs of humans by laser doppler flowmetry

2019 ◽  
Vol 17 (4) ◽  
pp. 33-38 ◽  
Author(s):  
L. V. Mezentseva
Keyword(s):  
Nonlinear Dynamics ◽  
Blood Flow ◽  
Laser Doppler Flowmetry ◽  
Coefficient Of Variation ◽  
Correlation Dimension ◽  
The Body ◽  
Doppler Flowmetry ◽  
Average Value ◽  
Flow Fluctuations ◽  
The Right

Purpose– the study the nonlinear dynamics of microcirculation parameters in human symmetrical organs.Material and Methods. Parameters of microcirculation were measured in healthy volunteers (aged between 50 and 70 years) by means of laser Doppler flowmetry (LDF). LDF signal transducers were fixed symmetrically on the lower parts of the right and left shoulders (3 cm above the elbow bend). The degree of chaoticity of microcirculation parameters as a nonlinear dynamic process was estimated using Hausdorff’s index, relative entropy and characteristics of phase portraits. Along with components of the amplitude-and-frequency range for blood flow fluctuations (myogenic, neurogenic, respiratory, and cardiac) was estimated and correlations between all characteristics of microcirculation in both sides of the body were done.Results.Asymmetry of correlation relationships of nonlinear dynamics parameters and components of the amplitude-andfrequency range for blood flow fluctuations of right and left sides of the body was revealed. Hausdorff index in the left side correlated not only with the average value of perfusion and with the coefficient of variation in the same side (r1 = –0,68; r2 =–0,51), but also with correlation dimension of chaos in the opposite side (r=0,49). Similarly, entropy in the left side correlated not only with the average value of perfusion and coefficient of variation in the left (r1 =0,43; r2 =0,60), but also with the entropy and correlation dimension of chaos in the right side (r1 =0,48; r2 =–0,41). The neurogenic component in the left side positively correlated with the myogenic component in the same side (r=0,71). A positive correlation was observed between the neurogenic component in right side and myogenic component in the opposite side (r=0,57). Asymmetry of correlation relationships was also revealed for the respiratory and cardiac components.Conclusions. Our results illustrate the specific regulation of blood flow in micro vessels of paired organs, which is associated with functional asymmetry. The physiological mechanisms for this asymmetry require further experimental and clinical studies. 

scholarly journals Laser doppler flowmetry for human blood microcirculation assessment

2014 ◽  
Vol 95 (1) ◽  
pp. 63-69 ◽  
Author(s):  
I V Barhatov
Keyword(s):  
Blood Flow ◽  
Frequency Analysis ◽  
Laser Doppler Flowmetry ◽  
Maximum Amplitude ◽  
Blood Perfusion ◽  
Laser Doppler ◽  
Doppler Flowmetry ◽  
Functional Changes ◽  
Microcirculatory Disorders ◽  
The Impact

The prevention and treatment of various microcirculation disorders are one of the most important problems of medical practice. The difficulties of studying the microcirculation are related to the blood vessels small size and extensive branching within organ tissues. At present, various methods of microcirculation assessment using the laser Doppler flowmetry are applied in active clinical practice in our country. The review covers the main methods of laser Doppler flowmetry used for the diagnosis of various microcirculation disorders. The method is based on the determination of tissue blood perfusion by measuring the Doppler frequency shift while tissue is illuminated by a laser beam, followed by the registration of the reflected radiation from moving and stationary tissue components. Microcirculatory oscillation rhythm plays an important role, especially in early diagnosis of many diseases. The loss of certain types of oscillations at laser Doppler flowmetry is interpreted as «spectral narrowing» and serves as a diagnostic criterion for microcirculation deregulation, which is directly related to decreased blood perfusion and tissue hypotrophy. The use of amplitude-frequency analysis of blood flow oscillations can non-invasively evaluate the impact of the various components of microvascular tone, allowing to calculate an index of neurogenic and myogenic tone and bypass index. The amplitude-frequency analysis of the laser Doppler flowmetry spectrum uses normalized parameters determining the maximum amplitude of the blood flow oscillation in different bands, as well as their ratio - microcirculation effectiveness index. Hyperemic, spastic, spastic-atonic, structural and degenerative, congestive and stasic forms of various microcirculation disorders are marked out. Each of these microcirculatory disorders is characterized by a certain ratio of structural and functional changes and changes in blood velocity, as well as impaired barrier function. The main principles of the microcirculatory disorders are described.

scholarly journals Investigation of changes in the skin blood microcirculation when performing the hatha yoga breathing technique

2022 ◽  
Vol 20 (4) ◽  
pp. 33-44
Author(s):  
A. V. Frolov ◽  
Yu. I. Loktionova ◽  
E. V. Zharkikh ◽  
V. V. Sidorov ◽  
A. I. Krupatkin ◽  
...  
Keyword(s):  
Blood Flow ◽  
Laser Doppler Flowmetry ◽  
Circulatory System ◽  
Low Frequency ◽  
Brain Perfusion ◽  
The Body ◽  
Laser Doppler ◽  
Regulatory Mechanisms ◽  
Doppler Flowmetry ◽  
Breathing Exercises

Introduction. Yoga breathing exercises improve the ability to significantly reduce the respiratory rate. A decrease of the minute respiration volume results in compensatory reactions of the microcirculatory bed caused by changes in the gas composition. The reaction of the regulatory mechanisms of the microvascular bed can be evaluated by the optical non-invasive laser Doppler flowmetry method. The aim of the study was to assess the tissue microcirculation parameter changes in people performing yoga breathing exercises. Materials and methods. 25 volunteers performed yoga breathing exercises at a frequency of 3 times per minute, 2 times per minute, 1.5 times per minute, 1 time per minute for 5 minutes, and free breathing for 6 minutes before and after breathing exercises. Parameters aimed to defin the reaction of skin microcirculation in different body areas were simultaneously recorded in six sites by laser Doppler flowmetry using a distributed system of wearable analyzers. The parameters of tissue microcirculation recorded by the method of laser Doppler flowmetry were: the index of microcirculation (Im), nutritive blood flow (Imn), the amplitude of myogenic (Am), neurogenic (An), endothelial (Ae), respiratory (Ar) and cardiac (Ac) regulation circuits. Results. Yoga breathing exercises led to increase of microcirculation index at all breathing frequencies. Breathing at a frequency of 1.5 and 1/minute leads to a significant increase in nutritional blood flow. Low-frequency breathing exercises lead to an increase in blood pressure at the lowest breathing rates – 1.5/minute and 1/minute. The most significant changes were achieved at the lowest respiration rates (1 and 1.5/minute), that could be associated with hypoxic-hypercapnic mechanisms. Conclusion. The absence of significant changes in microcirculation parameters after low-frequency respiration during measurements in the supraorbital arteries in both groups characterizes the work of homeostatic mechanisms for maintaining brain perfusion in stressful situations for the body (low-frequency types of respiration, hypercapnia and hypoxia). When measured in the extremities, a change in the effect of the circulatory system regulatory mechanisms was observed; along with an increase in skin perfusion and the nutritional component, it can characterize the compensatory reaction of the microcirculation to respiration change.

Peculiarities of microcirculation in periodont tissues in children of key age groups sufficient type 1 diabetes. Part II

2019 ◽  
Vol 24 (2) ◽  
pp. 108-119 ◽  
Author(s):  
B. N. Davydov ◽  
D. A. Domenyuk ◽  
S. V. Dmitrienko
Keyword(s):  
Diabetes Mellitus ◽  
Blood Flow ◽  
Type 1 Diabetes ◽  
Type 1 Diabetes Mellitus ◽  
Laser Doppler Flowmetry ◽  
Laser Doppler ◽  
Diabetic Microangiopathy ◽  
Healthy Children ◽  
Doppler Flowmetry

Relevance. Morpho-functional changes in peripheral circulation established in type 1 diabetes mellitus correlate with changes in central hemodynamics, allowing the use of microcirculation indicators as diagnostic and prognostic criteria for assessing the degree of functional vascular disorders. Identifcation of microcirculation features of the blood by the method of laser Doppler flowmetry in children with different experience of type 1 diabetes in key age categories.Materials and methods. The study included 67 children with type 1 diabetes mellitus aged 12-15 years with an experience of the disease from six months to ten years. The comparison group consisted of 38 healthy children. The state of the microvasculature was assessed by laser Doppler flowmetry using a laser analyzer for capillary blood flow LAKK-OP.Results. In children with an experience of type 1 diabetes of less than two years, microcirculation disorders in periodontal tissues correspond to the hyperemic form, accompanied by increased perfusion, a decrease in the amplitude of low-frequency oscillations, increased heart rate, high blood flling, and blood flow bypass. For children with an endocrinopathy experience of more than three years, microcirculation disorders correspond to a stagnant form, combined with a decrease in perfusion due to stagnation of blood in the venular link, endothelial domination with suppression of neurogenic and cardiac fluctuations, low efciency and redistribution of blood flow in favor of the nutritive link.Conclusions. With the increase in experience, the degree of compensation of type 1 diabetes, the progression of diabetic microangiopathy, it is advisable to designate two stages of development of microcirculatory disorders. Early – compensatory with active adaptation, including neurogenic and endothelial regulation mechanisms. Late – decompensation with passive adaptation, supporting the effectiveness of microcirculation due to myogenic control of regulation, shunting and increasing the rate of blood outflow.

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