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

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.

Microcirculation disorders in patients with severe COVID-19 and development of bacterial sepsis

It is believed that microcirculation dysfunction in sepsis primarily caused by damage of the endothelium by infectious agents and pro-inflammatory cytokines. Mechanisms of impaired microcirculation in the severe course of COVID-19 and sepsis likely to be similar. However, there are few reports studied microcirculation disorders in patients with COVID-19, and their results are sometimes contradictory. Objective. To assess the microcirculation of patients with severe Covid-19 and the development of bacterial sepsis using nail bed microscopy and laser Doppler flowmetry. Materials and methods. 16 intensive care unit COVID-19 patients subsequently diagnosed with bacterial sepsis were examined. Patients underwent vital capillaroscopy and an occlusive test using laser Doppler flowmetry. The average rate of capillary blood flow, the size of the perivascular zone, the density of capillaries, the presence of intravascular aggregates, the increase in the amplitude of the maximum post-occlusive blood flow and the average value of postocclusive blood flow relative to the initial one were valuated. Additionally, the level of serum proadrenomedullin was evaluated. Studies were performed on the day of admission and in dynamics. Results. By the capillaroscopy analysis, microcirculation disorders were detected in the form of a decrease in the linear speed of capillary blood flow (<400 μm/s), an extention of the perivascular zone (>100 μm), the circulation of microaggregates; the absence of postocclusive hyperemia was determined by an occlusive test. Secondary bacterial infection led to an even greater aggravation of microcirculation disorders: an increase of the perivascular zone, the progression of intravascular aggregation resulting in microthrombosis with a decrease of the density of the capillary network (according to capillaroscopy), as well as a sharp decrease of amplitude maximal increment of blood flow of post-осclusive circulation at the time of an occlusive sample. We also revealed a trend of negative correlation between the level of serum proadrenomedullin and the maximum increase in blood flow during the occlusive test. Conclusion. The secondary bacterial infection in patients with COVID-19 leads to a significant aggravation of microcirculation disorders with the development of perfusion deficiency and interstitial edema. The increased plasma proadrenomedullin level supports the concept of the significant role of endothelial dysfunction in the pathogenesis of severe COVID-10 and bacterial sepsis.

Sex features of cutaneous microvasculature in healthy working-age people

Aim. To study sex characteristics of cutaneous microvascular structure and function in a cohort of healthy working-age people without cardiovascular diseases.Material and methods. The study included 35 healthy men (42±4 years) and 34 women (41 ±5 years). The cardiovascular system was assessed in all patients. The microcirculatory bed of the skin was investigated by the following non-invasive methods: 1) computerized video capillaroscopy; 2) laser Doppler flowmetry; 3) photoplethysmography.Results. According to computerized video capillaroscopy in men, compared with women, there was a smaller number of both functioning capillaries (78 vs 86 capillaries/mm2, respectively (p<0,05)) and their total number (100 vs 120 capillaries/mm2, respectively (p<0,001)). Against the background of a decrease in capillary density in men, there was a higher skin interstitial hydration — 113 vs 96 gm (p<0,005) in men than in women. At the level of precapillary arterioles, where humoral tone regulation prevails. Laser Doppler flowmetry revealed lower pulse amplitude in men than in women — 0,87 vs 1,02 pf, respectively (p<0,05), which indicates a lower arterial blood inflow to exchange microvessels. Against this background, the constrictor response of precapillary arterioles to a sympathetic nervous system stimulation in men is higher than in women — 45% vs 40%, respectively (p<0,05). At the level of large arterioles, where neural tone regulation prevails, photoplethysmography revealed lower augmentation index standardized at a heart rate in men (-4,6 vs 1,7%, respectively, p<0,05), which indicates lower rigidity of muscular vessels in men.Conclusion. In working-age healthy people, sex differences are noted at all cutaneous microvascular levels, which must be taken into account when planning studies.

Evaluation of Shoulder Microcirculation Abnormality Using Laser Doppler Flowmetry

Severe neck-shoulder pain induces functional limitations in both life and work. The purpose of this study was to determine the characteristics of shoulder microcirculation abnormality in workers. This study recruited 32 workers and patients, both n = 16. Questionnaires were administered, and Laser Doppler Flowmetry (LDF) was used to measure microcirculatory blood flow (MBF) at the myofascial trigger points (MTrPs) on the shoulders. The absolute-deviationMMBF represented the mean MBF (MMBF) variability among subjects. The differences in the life characteristics, shoulder pain level, and microcirculatory characteristics at MTrPs between the two groups were compared. It was found that shoulder pain level was significantly higher in the patient than in the control group (p < 0.001). Deviation of the MMBF value beyond the postulated “normal range” of 60–80 was significantly higher in the patient than in the control group (p < 0.001). The MMBF deviation was significantly correlated with shoulder pain level, pain duration, and the symptom effect (p < 0.01, n = 32). A normal range for the MMBF of 60–80 on the shoulder near MTrPs is hypothesized for the first time based on this study. Noninvasive LDF can be used to assess abnormality in the MBF on shoulder MTrPs at an early stage.

Prospects for the use of laser Doppler flowmetry to assess cutaneous blood microcirculation in diabetes mellitus

The аrticle considers the scientific and clinical aspects of laser Doppler flowmetry (LDF) in the diagnosis of the state of the microcirculatory bed in diabetes mellitus. LDF is a non-invasive quantitative method of microcirculation assessment; its capabilities include the analysis of microcirculatory rhythms and functional testing with different types of provocation tests, which provides a study of the state of regulatory mechanisms of microcirculation. The difficulties with studying the microcirculation are caused by the very small size of microvessels. The prevention and treatment of various microcirculatory disorders is one of the most important problems in medical practice. The findings of some studies suggest that microcirculatory disorders are not only a pathogenetic link in the development of complications, but are also observed in patients with early disorders of carbohydrate metabolism and may precede the manifestation of diabetes mellitus. The use of LDF in scientific researches will make it possible to reveal changes in microcirculatory bed functioning that are characteristic of diabetes mellitus. The possibility of non-invasive quantitative assessment of the state of microcirculatory blood flow in real time and the relative ease of use explains the high popularity of LDF in scientific researches and makes this method promising for use in clinical practice. This method can be of important diagnostic value for the study of the state of different levels of regulation of the microcirculatory tract and dynamic monitoring of the effectiveness of the prescribed treatment. Combined use of LDF to identify the risk of developing diabetic foot syndrome will allow to personify the treatment of diabetes. Among the most promising points of application should be noted the study of microcirculation in the early diagnosis of diabetes and its complications, clarifying the risk of complications, monitoring the effectiveness of treatment. The development of optimal evaluation methods of microcirculation is a prospect for further research.

Laser doppler flowmetry as the advanced non-invasive method of evaluation оf microcirculation status in patients with diabetes mellitus

Currently, the problem of diabetes mellitus (DM) is one of the most important medical and social challenges worldwide. This is primarily due to the widespread prevalence of the disease and tendency to further increase in the incidence of diabetes mellitus.Systemic microcirculatory disorders play an impor­tant role in the pathogenesis of DM complications. They lead to the development of microangiopathy and neuropathy through the primary lesion of vessels involved in the blood supply of the peripheral parts of the nervous system. Currently, less than one-third of physicians recognize signs of peripheral neuropathy associated with diabetes. Untimely diagnosis contributes significantly to high morbidity, disability, and mortality.The authorinvestigates the experience of the use of laser Doppler flowmetry (LDF) in clinical practice as a method of studying the state of the microcirculatory bed in patients with diabetes mellitus.LDF is a non-invasive quantitative method of microcirculation assessment; its capabilities include the analysis of microcirculatory rhythms and functional testing with different types of provocative effects, which provides with investigating the state of regulatory mechanisms of microcirculation. The prevention and treatment of various microcirculatory disorders is one of the most important problems of medical practice. The difficulties of studying the microcirculation are caused by the very small size of microvessels and strong ramification of intra-organic vascular networks. The use of LDF in scientific research will make it possible toreveal the DM-specific changes in microcir­culatory bed functioning. The findings of some studies suggest that microcirculatory disorders are not only a pathogenetic link in the development of complications, but they are also observed in patients with early disorders of carbohydrate metabolism and may precede the manifestation of diabetes. However, the method has not yet become widespread in clinical practice.

Evaluation of changes in laser Doppler flowmetry indices in patients with a combined subtype of rosacea under the influence of a course of complex phototherapy

BACKGROUND: The development of new methods for the treatment of rosacea, as well as a combination of various methods of physiotherapy, is of scientific and practical interest. In this work, the assessment of changes in microcirculation indices under complex phototherapy has been carried out. AIMS: Тo assess changes in microcirculation indices in patients with a combination of rosacea subtypes according to laser Doppler flowmetry under a course of complex phototherapy. MATERIAL AND METHODS: In 20172020 a randomized controlled study of 130 patients with a combination of rosacea subtypes. All patients were divided into 4 groups. In each separate group, laser therapy and 1% metronidazole cream were used (group I); phototherapy and 1% metronidazole cream (group II); complex photolaser therapy and 1% metronidazole cream (group III); in the comparison group (group IV), patients show only 1% metronidazole cream. The treatment, the duration of which was 3 months, included 6 sessions with an interval of 2 weeks. The effectiveness of therapy was assessed according to the data of laser Doppler flowmetry, reflecting changes in the hemodynamics of the microvasculature in the affected skin areas. RESULTS: The developed complex method, including exposure to intense pulsed light (intense pulsed light, IPL) 5201100 nm in combination with submillisecond neodymium laser radiation 1064 nm (submilisecond Nd: YAG laser 1064 nm) and daily application of 1% metronidazole cream showed the most pronounced improvement in the state of microcirculation according to laser Doppler flowmetry in comparison with the rest groups. Against the background of the course of complex phototherapy for all patients with the combined subtype of rosacea, statistically significant changes were in the volume of blood flow, modulation coefficients, coefficient of variation. On the contrary, no statistically significant changes were found in the ranges corresponding to active regulatory factors endothelial, neurogenic, myogenic, and passive respiratory and cardiac, as well as in the T index. CONCLUSION: After the course of complex phototherapy in the group of patients with a combination of rosacea subtypes, there was a decrease in the severity of clinical manifestations of diseases, as well as an improvement in the main indicators of microcirculation according to laser Doppler flowmetry.