scholarly journals Exposure to acute normobaric hypoxia results in adaptions of both the macro- and microcirculatory system

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Moritz Mirna ◽  
Nana-Yaw Bimpong-Buta ◽  
Fabian Hoffmann ◽  
Thaer Abusamrah ◽  
Thorben Knost ◽  
...  
Keyword(s):  
Cardiac Output ◽  
Acute Hypoxia ◽  
Capillary Density ◽  
Dark Field ◽  
Normobaric Hypoxia ◽  
Vessel Density ◽  
Resistance Arteries ◽  
Compensatory Mechanisms ◽  
Sidestream Dark Field ◽  
Sublingual Microcirculation

AbstractAlthough acute hypoxia is of utmost pathophysiologic relevance in health and disease, studies on its effects on both the macro- and microcirculation are scarce. Herein, we provide a comprehensive analysis of the effects of acute normobaric hypoxia on human macro- and microcirculation. 20 healthy participants were enrolled in this study. Hypoxia was induced in a normobaric hypoxia chamber by decreasing the partial pressure of oxygen in inhaled air stepwisely (pO2; 21.25 kPa (0 k), 16.42 kPa (2 k), 12.63 kPa (4 k) and 9.64 kPa (6 k)). Macrocirculatory effects were assessed by cardiac output measurements, microcirculatory changes were investigated by sidestream dark-field imaging in the sublingual capillary bed and videocapillaroscopy at the nailfold. Exposure to hypoxia resulted in a decrease of systemic vascular resistance (p < 0.0001) and diastolic blood pressure (p = 0.014). Concomitantly, we observed an increase in heart rate (p < 0.0001) and an increase of cardiac output (p < 0.0001). In the sublingual microcirculation, exposure to hypoxia resulted in an increase of total vessel density, proportion of perfused vessels and perfused vessel density. Furthermore, we observed an increase in peripheral capillary density. Exposure to acute hypoxia results in vasodilatation of resistance arteries, as well as recruitment of microvessels of the central and peripheral microcirculation. The observed macro- and microcirculatory effects are most likely a result from compensatory mechanisms to ensure adequate tissue oxygenation.

scholarly journals Characteristics and Clinical Significance of Microcirculation in Populations Residing at Different Altitudes

2020 ◽  
Author(s):  
Siqing Ma ◽  
Zong-Zhao He ◽  
Jun-Ming Luo ◽  
Kang Song ◽  
Jing-Yuan Xu ◽  
...  
Keyword(s):  
Field Method ◽  
Dark Field ◽  
Vessel Density ◽  
Physiological Adaptation ◽  
Flow Index ◽  
Sidestream Dark Field ◽  
Blood Oxygen Saturation ◽  
Cell Parameters ◽  
Sublingual Microcirculation ◽  
Different Altitudes

Abstract Background: This study aimed to evaluate changes in microcirculation, physiological characteristics, and the pathomechanism of and potential treatment alternatives for severe septic shock among healthy individuals residing at different altitudes.Methods: Seventy individuals, 35 from Xining and 35 from Nanjing, were recruited, and their body temperature, pulse, respiration, mean arterial pressure, peripheral blood oxygen saturation, and blood cell parameters were determined. Microcirculation indices of sublingual microcirculation were monitored using the sidestream dark field method.Results: Erythrocyte counts and hemoglobin levels were significantly higher among individuals from Xining than among those from Nanjing (P < 0.05); however, platelet counts were significantly lower among those from Xining (P < 0.05). Microcirculation indices of total vessel density, perfused vessel density, and the proportion of perfused vessels were significantly higher among individuals from Xining than among those from Nanjing; however, the microvascular flow index was lower among those from Xining. Microvascular density was significantly higher among individuals from Xining than among those from Nanjing.Conclusion: Microvascular densit may be a physiological adaptation among populations at moderate-to-high altitudes.

Abstract 2044: Selective Head Cooling Initiated during Cpr Induces Post-Resuscitation Carotid Artery Dilation and Increases in Carotid Artery Flow and Cerebral Cortical Microcirculation

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Giuseppe Ristagno ◽  
Jun H Cho ◽  
Tao Yu ◽  
Shijie Sun ◽  
Max H Weil ◽  
...  
Keyword(s):  
Carotid Artery ◽  
Common Carotid Artery ◽  
Brain Temperature ◽  
Capillary Density ◽  
Dark Field ◽  
Sidestream Dark Field ◽  
Blood Flows ◽  
Dark Field Imaging ◽  
Head Cooling ◽  
Artery Flow

Introduction. We have previously reported that selective head cooling initiated during CPR prevented increases in brain temperature and improved neurological outcome. In the present study, we explored the relationship between head cooling during CPR and cerebral blood flows. We hypothesized that head cooling during CPR would yield carotid artery dilation with consequent increases in carotid flows and cerebral cortical microcirculation. Methods. Eight pigs weighing 37 ± 1 kg were intubated and mechanically ventilated. The common carotid artery was isolated and a parietal craniotomy was created. Ventricular fibrillation was electrically induced and untreated for 4 min. Animals were then randomized to head cooling or control. Head cooling was initiated with the aid of the RinoChill device (BeneChill Inc) at the beginning of CPR. CPR was performed for 4 min prior to defibrillation. Common carotid artery diameter and flow were assessed with a Doppler transducer. Cerebral cortical capillary density, representing the number of perfused capillaries, was assessed with Sidestream Dark Field imaging (MicroVisionMedical Inc). Brain temperature was measured with a needle sensor inserted in the cerebral cortex. Results. All the animals were resuscitated. After resuscitation, the brain temperature was significantly decreased in animals subjected to head cooling. Significantly greater carotid artery diameters and flows were observed in animals subjected to selective head cooling compared to the control animals. These increases in carotid blood flows were accompanied by significantly greater numbers of perfused capillaries in the cerebral cortices. No differences in cardiac output were observed between the two groups (Table ). Conclusion. Early selective head cooling induces carotid artery dilation and increases in carotid flows and cerebral cortical microcirculation after resuscitation.

Abstract MP61: Evidence of Impaired Microvascular Function a Decade After Delivery in Women With Placental Malperfusion Lesions

Circulation ◽  
2020 ◽  
Vol 141 (Suppl_1) ◽  
Author(s):  
Alisse Hauspurg ◽  
Judith Brands ◽  
Robin Gandley ◽  
Matthew F Muldoon ◽  
William Tony Parks ◽  
...  
Keyword(s):  
Disease Risk ◽  
Gestational Hypertension ◽  
Boundary Region ◽  
Dark Field ◽  
Endothelial Glycocalyx ◽  
Sidestream Dark Field ◽  
Sublingual Microcirculation ◽  
Dark Field Imaging ◽  
Median Diameter ◽  
History Of

Introduction: Maternal vascular malperfusion (MVM) lesions in the placenta are characterized by incomplete vascular remodeling and vessel features similar to atherosclerosis. MVM lesions indicate a maladaptive maternal vascular response to pregnancy, are often detected in hypertensive disorders of pregnancy (HDP), and may provide a pathologic link to future cardiovascular disease. The endothelial glycocalyx is a glycoprotein-rich layer that is critical for microvascular health and damage may have an important role in the pathophysiology of microcardiovascular disease risk. Hypothesis: We hypothesized that women with malperfusion lesions of the placenta are more likely to evidence microvascular glycocalyx derangement a decade after delivery compared to women without these lesions and that this effect would be most pronounced among women with a history of HDP. Methods: A total of 412 women with placental pathology (N=129 with MVM lesions, N=283 without MVM lesions) were evaluated at 8-10 years postpartum. Placental specimens were reviewed by a blinded perinatal pathologist . HDP (including preeclampsia and gestational hypertension) were abstracted from the medical record. Glycocalyx barrier function was assessed using sublingual sidestream dark field imaging, with reduction defined as deeper penetration of red blood cells (RBCs) into the glycocalyx of the sublingual microcirculation (5-25μm diameter). We compared the median diameter (size) of microvessels, penetration of RBCs into the glycocalyx (perfused boundary region, PBR) and microvascular density (total length of perfused microvessels/mm 2 surface area) in women with and without MVM lesions. Results: Women with placental MVM lesions had smaller-sized sublingual vessels (median 8.59 μM [IQR 8.12, 9.19] vs. 9.01 μM [IQR 8.37, 9.64]; p<0.001), and a lower density of vessels compared to women without lesions. Glycocalyx perfused boundary region was unexpectedly lower in women with MVM lesions (median 2.20 μM [IQR 2.06, 2.43] vs. 2.32 μM [IQR 2.15, 2.50]; p=0.003) in 10-19 μM vessels. Women with HDP and MVM lesions appear to be the most impacted, with the smallest size vessels (median 8.47 [IQR 8.09-9.13]) and the lowest glycocalyx PBR across all vessel sizes. Women with MVM lesions without a HDP similarly had evidence of microvascular glycocalyx derangement whereas women with HDP without placental lesions had a glycocalyx profile similar to women without MVM or a history of HDP. Conclusions: A decade after delivery, women with a history of placental malperfusion lesions had alterations in microvascular perfusion. Women with MVM lesions and a history of HDP appear to be the most severely impacted, which may reflect an underlying maladaptive vascular phenotype detected in the placenta at the time of pregnancy that might provide pathologic insight into future maternal microvascular health.

scholarly journals In Situ Assessment of the Brain Microcirculation in Mechanically-Ventilated Rabbits Using Sidestream Dark-Field (SDF) Imaging

2011 ◽  
pp. 75-81 ◽  
Author(s):  
M. ŠITINA ◽  
Z. TUREK ◽  
R. PAŘÍZKOVÁ ◽  
V. ČERNÝ
Keyword(s):  
Dark Field ◽  
Vessel Density ◽  
Flow Index ◽  
Target Tissue ◽  
Cerebral Microcirculation ◽  
Sidestream Dark Field ◽  
Mechanically Ventilated ◽  
Sdf Imaging ◽  
The Brain

Assessment of the cerebral microcirculation by on-line visualization has been impossible for a long time. Sidestream dark-field (SDF) imaging is a relatively new method allowing direct visualization of cerebral surface layer microcirculation using hand-held probe for direct contact with target tissue. The aim of this study was to elucidate the feasibility of studying the cerebral microcirculation in situ by SDF imaging and to assess the basic cerebral microcirculatory parameters in mechanically ventilated rabbits. Images were obtained using SDF imaging from the surface of the brain via craniotomy. Clear high contrast SDF images were successfully obtained. Total small-vessel density was 14.6±1.8 mm/mm2, total all-vessel density was 17.9±1.7 mm/mm2, DeBacker score was 12.0±1.6 mm-1 and microvascular flow index was 3.0±0.0. This method seems to be applicable in animal studies with possibility to use SDF imaging also intraoperatively, providing unique opportunity to study cerebral microcirculation during various experimental and clinical settings.

VS03.01: QUANTITATIVE IMAGING OF CHANGE IN MICROCIRCULATION BY SIDESTREAM DARK FIELD MICROSCOPY (SDF) AFTER ESOPHAGECTOMY

2018 ◽  
Vol 31 (Supplement_1) ◽  
pp. 47-48
Author(s):  
Sanne Jansen ◽  
Daniel De Bruin ◽  
Mark I Van Berge Henegouwen ◽  
Ton Van Leeuwen ◽  
Suzanne Gisbertz
Keyword(s):  
Anastomotic Leakage ◽  
Gastric Tube ◽  
Average Velocity ◽  
Venous Return ◽  
Conflicts Of Interest ◽  
Dark Field ◽  
Vessel Density ◽  
Flow Index ◽  
High Morbidity ◽  
Sidestream Dark Field

Abstract Description Anastomotic leakage is one of the most severe complications after esophageal resection with gastric tube reconstruction. Impaired perfusion of the gastric fundus is seen as the main contributing factor for this complication. Transection of the left gastric and gastro-epiploic artery and veins results in compromised perfusion in the fundus area which can result in anastomotic dehiscence (5–20%), relating to high morbidity and mortality (3–4%). The main objective of this observational study is to evaluation gastric tube microcirculation with Sidestream Darkfield Microscopy (SDF). Method This study included 22 patients (October 2015 - June 2016). Intra-operative microscopic images of gastric tube microcirculation were obtained with SDF directly after reconstruction. Using software (AVA2.0), the following parameters were evaluated: average velocity (μm/sec), Microvascular Flow Index (MFI), Total Vessel Density (TVD), Perfusion Vessel Density (PVD), Proportion of Perfused Vessels (PPV) and the De Backer Score (DBS), to assess change in perfusion. Results SDF accurately visualized and evaluated microcirculation in all patients. A SDF-stabilizer was used to create stable images. The average velocity decreased significantly towards the fundus (P = 0.001). Also, MFI, PVD and PPV were significantly lower towards the fundus, compared to the base of the gastric tube (P = 0.0002). No differences in TVD and DBS were observed, which was associated to the observed vessel dilation in the fundus-area. This vessel dilation proposes that compromised venous return may play an important role in the development of necrosis and leakage. Three patients developed anastomotic leakage. Conclusion This is the first study presenting quantitative microcirculation imaging with SDF of the gastric tube. Velocity, MFI, TVD and PPV were accurate parameters to observe change in perfusion after reconstruction. Also, vessel dilation in the fundus suggests a role for venous return in the development of ischemia. Quantitative microcirculation with SDF could allow for intra-operative early risk stratification, and, potentially, can result in a reduction of anastomotic leakage. Disclosure All authors have declared no conflicts of interest.

Bevacizumab-related hypertension: Search for underlying mechanisms

2009 ◽  
Vol 27 (15_suppl) ◽  
pp. e14520-e14520
Author(s):  
N. Steeghs ◽  
T. J. Rabelink ◽  
J. op ’t Roodt ◽  
E. de Koning ◽  
H. Gelderblom
Keyword(s):  
Blood Pressure ◽  
Vascular Function ◽  
Capillary Density ◽  
Aortic Pulse Wave Velocity ◽  
Dark Field ◽  
Sidestream Dark Field ◽  
Angiogenic Therapy ◽  
Bevacizumab Treatment ◽  
Flow Mediated Dilatation ◽  
Underlying Mechanisms

e14520 Background: Hypertension is a commonly observed side effect of inhibitors of VEGF/VEGFR-2 signaling such as bevacizumab. The mechanisms leading to this increase in blood pressure during anti-angiogenic therapy have not been elucidated. Recent studies suggest that functional rarefaction (a decrease in perfused microvessels) or anatomic rarefaction (a reduction in capillary density) may play an important role. The purpose of this study was to search for possible mechanisms that cause hypertension in patients treated with anti-angiogenic therapy and to confirm our hypothesis that systemic inhibition of VEGF inhibits vascular function and causes rarefaction. Methods: Patients treated with bevacizumab for any type of cancer were eligible. Measurements of blood pressure, flow-mediated dilatation (FMD), nitroglycerin-mediated dilatation (NMD), aortic pulse wave velocity (PWV), and capillary density and diameter with sidestream dark field (SDF) imaging of the mucosal microcirculation of the lip were performed at baseline, after 6 weeks of treatment, and 3 months after discontinuation of bevacizumab treatment. Results: Fourteen patients were included in this study. During bevacizumab treatment the mean systolic and diastolic blood pressure values increased, +3.4 mmHg (p=0.406), and +5.6 mmHg (p=0.023) resp. Mean FMD showed a statistically significant decrease of -3.1% (p=0.006). Mean NMD was unchanged. After 6 weeks treatment mean PWV increased significantly +0.7 m/s (p=0.0.027). A significant reduction in capillary density was seen from 18.0 capillary loops per image at baseline to 12.7 after 6 weeks (p=0.000007). Also a significant reduction in capillary diameter was seen, from 6.9 to 5.6 μm (p=0.002). Results after discontinuation of bevacizumab treatment were not yet available. Conclusions: Rarefaction (reduction in capillary density) and endothelial dysfunction observed in this study provide a plausible mechanism for the increase in blood pressure which results from treatment with bevacizumab. No significant financial relationships to disclose.

scholarly journals Effects of a single aerobic exercise on perfused boundary region and microvascular perfusion: a field study

2021 ◽  
Author(s):  
Alexander Fuchs ◽  
Tobias Neumann ◽  
Hendrik Drinhaus ◽  
Anika Herrmann ◽  
Hans Vink ◽  
...  
Keyword(s):  
Surface Layer ◽  
Aerobic Exercise ◽  
Linear Regression Analysis ◽  
Boundary Region ◽  
Dark Field ◽  
Microvascular Perfusion ◽  
Sidestream Dark Field ◽  
Endothelial Surface Layer ◽  
Sublingual Microcirculation ◽  
Endothelial Surface

AbstractThe endothelium and the glycocalyx play a pivotal role in regulating microvascular function and perfusion in health and critical illness. It is unknown today, whether aerobic exercise immediately affects dimensions of the endothelial surface layer (ESL) in relation to microvascular perfusion as a physiologic adaption to increased nutritional demands. This monocentric observational study was designed to determine real-time ESL and perfusion measurements of the sublingual microcirculation using sidestream dark field imaging performed in 14 healthy subjects before and after completing a 10 km trial running distance. A novel image acquisition and analysis software automatically analysed the perfused boundary region (PBR), an inverse parameter for red blood cell (RBC) penetration of the ESL, in vessels between 5 and 25 µm diameter. Microvascular perfusion was assessed by calculating RBC filling percentage. There was no significant immediate effect of exercise on PBR and RBC filling percentage. Linear regression analysis revealed a distinct association between change of PBR and change of RBC filling percentage (regression coefficient β: − 0.026; 95% confidence interval − 0.043 to − 0.009; p = 0.006). A single aerobic exercise did not induce a change of PBR or RBC filling percentage. The endothelium of the microvasculature facilitates efficient perfusion in vessels reacting with an increased endothelial surface layer.

Evaluation of a shorter algorithm in an automated analysis of sublingual microcirculation

2020 ◽  
Vol 76 (2) ◽  
pp. 287-297
Author(s):  
Raphael Romano Bruno ◽  
Mara Schemmelmann ◽  
Jakob Wollborn ◽  
Malte Kelm ◽  
Christian Jung
Keyword(s):  
Video Quality ◽  
Quality Measurement ◽  
Automated Analysis ◽  
Measurement Procedure ◽  
Dark Field ◽  
Frame Rate ◽  
Sidestream Dark Field ◽  
Sublingual Microcirculation ◽  
Promising Tool ◽  
Measurement Results

OBJECTIVE: Diagnostic and risk stratification in intensive and emergency medicine must be fast, accurate, and reliable. The assessment of sublingual microcirculation is a promising tool for this purpose. However, its value is limited because the measurement is time-consuming in unstable patients. This proof-of-concept validation study examines the non-inferiority of a reduced frame rate in image acquisition regarding quality, measurement results, and time. METHODS: This prospective observational study included healthy volunteers. Sublingual measurement of microcirculation was performed using a sidestream dark field camera (SDF, MicroVision Medical®). Video-quality was evaluated with a modified MIQS (microcirculation image quality score). AVA 4.3C software calculated microcirculatory parameters. RESULTS: Thirty-one volunteers were included. There was no impact of the frame rate on the time needed by the software algorithm to measure one video (4.5 ± 0.5 minutes) for AVA 4.3C. 86 frames per video provided non inferior video quality (MIQS 1.8 ± 0.7 for 86 frames versus MIQS 2.2 ± 0.6 for 215 frames, p < 0.05), equal results for all microcirculatory parameters, but did not result in an advantage in terms of speed. No complications occurred. CONCLUSION: Video captures with 86 frames offer equal video quality and results for consensus parameters compared to 215 frames. However, there was no advantage regarding the time needed for the overall measurement procedure.

scholarly journals Experience of Sublingual Microcirculation Evaluation in Adults Patients with Severe Dengue

2017 ◽  
Vol 4 (suppl_1) ◽  
pp. S360-S360
Author(s):  
Fernando Rosso ◽  
Gustavo Ospina ◽  
Edgardo Quiñones ◽  
Ana Maria Sanz
Keyword(s):  
Fluid Challenge ◽  
Significant Negative Correlation ◽  
Dark Field ◽  
Severe Dengue ◽  
Flow Index ◽  
Vascular Density ◽  
Positive Serology ◽  
Volume Depletion ◽  
Sidestream Dark Field ◽  
Sublingual Microcirculation

Abstract Background Severe microcirculatory changes are involved in the pathophysiological mechanisms that lead to irreversible final stages of dengue shock. We report our experience of the evaluation of sublingual microcirculation in adult patients with severe dengue Methods Adults patients with severe dengue (by WHO 2009 criteria) were included. Dengue diagnostics was made by positive serology for IgM / IgG, antigen NS1 or PCR. Sublingual Microcirculation (SM) was evaluated by Sidestream Dark Field imaging. Microvascular flow index (MFI), proportion of small-perfused vessels (%SVP), heterogeneity index (HI) and Total Vascular Density were calculated. All patients received Fluids Challenge (FC) at hospital admission. Results SM was assessed in 10 patients. The median age was 65 years [IQR: 34–70], 60% were male. Eight patients were admitted to the ICU, of which 63% required invasive ventilatory and vasoactive support. One patient died. After the fluid challenge, the median of the %SVP was 94 [IR: 97 – 77], the median of the MFI was 2.82 [IR: 2, 85 – 2, 14]. There were not significant differences in %SVP and MFI among the patients who survived. In the deceased patient, the %SVP with continuous flow was 59, 18% and the MFI was 1, 45; these values were significantly decreased compared with patients who survived. A significant negative correlation between hematocrit and %SVP, and MFI was found. Conclusion Initial fluid challenge, that identifies and treats volume depletion, could correct microcirculation abnormalities evaluated by SDF imaging. However, in the patient who did not respond to this challenge, significant alterations of the MFI and the %SVP were evidenced. There is a need for more studies to improve our understanding of the role of microcirculation evaluation in these patients. Disclosures All authors: No reported disclosures.

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