scholarly journals Functional respiratory imaging identifies redistribution of pulmonary blood flow in patients with COVID-19

Thorax ◽  
2020 ◽  
pp. thoraxjnl-2020-215395
Author(s):  
Muhunthan Thillai ◽  
Chinmay Patvardhan ◽  
Emilia M Swietlik ◽  
Tom McLellan ◽  
Jan De Backer ◽  
...  
Keyword(s):  
Blood Volume ◽  
Pulmonary Blood Flow ◽  
Distress Syndrome ◽  
Management Strategies ◽  
Lung Compliance ◽  
Ct Scans ◽  
Normal Lung ◽  
Healthy Controls ◽  
Cross Sectional ◽  
Pulmonary Blood Volume

An increasing observation is that some patients with COVID-19 have normal lung compliance but significant hypoxaemia different from typical acute respiratory distress syndrome (ARDS). We hypothesised that changes in pulmonary blood distribution may be partially responsible and used functional respiratory imaging on CT scans to calculate pulmonary blood volume. We found that patients with COVID-19 had significantly reduced blood volume in the smaller calibre blood vessels (here defined as <5 mm2 cross-sectional area) compared with matched ARDS patients and healthy controls. This suggests that using high levels of PEEP may not alone be enough to oxygenate these patients and that additional management strategies may be needed.

scholarly journals Increased pulmonary blood volume variation in patients with heart failure compared to healthy controls: a noninvasive, quantitative measure of heart failure

2020 ◽  
Vol 128 (2) ◽  
pp. 324-337
Author(s):  
Mariam Al-Mashat ◽  
Jonas Jögi ◽  
Marcus Carlsson ◽  
Rasmus Borgquist ◽  
Ellen Ostenfeld ◽  
...  
Keyword(s):  
Heart Failure ◽  
Phase Shift ◽  
Pulmonary Artery ◽  
Blood Volume ◽  
Main Pulmonary Artery ◽  
Left Ventricular ◽  
Healthy Controls ◽  
Pulmonary Blood Volume ◽  
Volume Variation ◽  
Patients With Heart Failure

Variation of the blood content of the pulmonary vascular bed during a heartbeat can be quantified by pulmonary blood volume variation (PBVV) using magnetic resonance imaging (MRI). The aim was to evaluate whether PBVV differs in patients with heart failure compared with healthy controls and investigate the mechanisms behind the PBVV. Forty-six patients and 10 controls underwent MRI. PBVV was calculated from blood flow measurements in the main pulmonary artery and a pulmonary vein, defined as the maximum difference in cumulative PBV over one heartbeat. PBVV was indexed to stroke volume (SV) in the main pulmonary artery (PBVVSV). Patients displayed higher PBVVSV than controls (58 ± 14 vs. 43 ± 7%, P < 0.001). The change in PBVVSV could be explained by left ventricular (LV) longitudinal contribution to SV ( R2 = 0.15, P = 0.02) and the phase shift between in- and outflow ( R2 = 0.31, P < 0.001) in patients. Both variables contributed to the multiple regression analysis model and predicted PBVVSV ( R2 = 0.38); however, the phase shift alone explained ~30% of the variation in PBVVSV. No correlation was found between PBVVSV and large vessel area. In conclusion, PBVVSV was higher in patients compared with controls. Approximately 40% of the variation of PBVVSV in patients can be explained by the LV longitudinal contribution to SV and the phase shift between pulmonary in- and outflow, where the phase shift alone accounts for ~30%. The remaining variation (60–70%) most likely occurs on a small vessel level. Future studies are needed to show the clinical added value of PBVVSV compared with right-heart catheterization. NEW & NOTEWORTHY This study shows that the pulmonary blood volume variation indexed to the stroke volume is higher in patients with heart failure compared with controls. The mechanisms behind this are lack of systolic suction from the left ventricular atrioventricular plane descent and increased phase shift between the in- and outflow to the pulmonary circulation (~40%), where the phase shift alone accounts for ~30%. The remaining variation (60–70%) is suggested to occur on a small vessel level.

Active and passive components of pulmonary vascular response to vasoactive drugs in the dog

1963 ◽  
Vol 205 (6) ◽  
pp. 1193-1199 ◽  
Author(s):  
James W. Feeley ◽  
T. David Lee ◽  
William R. Milnor
Keyword(s):  
Blood Volume ◽  
Left Atrial ◽  
Pulmonary Blood Flow ◽  
Pulmonary Veins ◽  
Pleural Space ◽  
Vascular Response ◽  
Passive Components ◽  
Pulmonary Blood Volume ◽  
Isolated Lung ◽  
Hemodynamic Measurements

Pulmonary blood volume was altered by intravenous infusion of selected drugs. To determine whether these alterations were the result of active changes in pulmonary vascular distensibility or were simply passive, simultaneous hemodynamic measurements were made, including pulmonary blood flow, vascular resistance, and pressures in pulmonary artery, left atrium, small pulmonary veins, and pleural space. In most instances it was necessary to postulate a mixture of active and passive events to account for the results. Epinephrine and norepinephrine elevated left atrial pressure and thus led to passive distention of the pulmonary bed (mean pulmonary blood volume increment, closed chest: epinephrine + 2.6 ml/kg, or 24%; norepinephrine + 2.7 ml/kg, or 25%), in spite of the stiffening and vasoconstrictive effects previously demonstrated in the isolated lung. Isoproterenol increased the volume (+3.4 ml/kg, 31%) and lowered the resistance of the bed by increasing its distensibility, effects sometimes re-enforced by a rise in pressure secondary to increased output. Histamine produced active pulmonary venoconstriction, with passive distention upstream, so that net changes in volume and resistance were variable.

Observations on Cardiac Output and ”Pulmonary Blood Volume” in Normal Man by External Recording of the Intracardiac Flow of 131I Labelled Albumin

1961 ◽  
Vol 1 (04) ◽  
pp. 353-379
Author(s):  
Jacques Lammerant ◽  
Norman Veall ◽  
Michel De Visscher
Keyword(s):  
Cardiac Output ◽  
Blood Volume ◽  
Normal Subjects ◽  
Published Data ◽  
Total Blood Volume ◽  
Total Blood ◽  
Pulmonary Blood Volume ◽  
Intracardiac Flow ◽  
Normal Man ◽  
Mean Circulation

Summary1. The technique for the measurement of cardiac output by external recording of the intracardiac flow of 131I labelled human serum albumin has been extended to provide a measure of the mean circulation time from right to left heart and hence a new approach to the estimation of the pulmonary blood volume.2. Values for the basal cardiac output in normal subjects and its variations with age are in good agreement with the previously published data of other workers.3. The pulmonary blood volume in normal man in the basal state was found to be 28.2 ± 0.6% of the total blood volume.4. There was no correlation between cardiac output and pulmonary blood volume in a series of normal subjects in the basal state.5. The increase in cardiac output during digestion was associated with a decrease in pulmonary blood volume equal to 6.3 ± 1.2% of the total blood volume, that is, about 280 ml.6. The increase in cardiac output during exercise was associated with a decrease in pulmonary blood volume equal to 4.5 ± 1.0% of the total blood volume, that is, about 200 ml.7. The increase in cardiac output attributed to alarm is not associated with a decrease in pulmonary blood volume, the latter may in fact be increased.8. The total blood volume is advocated as a standard of reference for studies of this type in normal subjects in preference to body weight or surface area.9. The significance of these results and the validity of the method are discussed.

Mechanisms of improvement in pulmonary gas exchange during isovolemic hemodilution

1999 ◽  
Vol 87 (1) ◽  
pp. 132-141 ◽  
Author(s):  
Steven Deem ◽  
Richard G. Hedges ◽  
Steven McKinney ◽  
Nayak L. Polissar ◽  
Michael K. Alberts ◽  
...  
Keyword(s):  
Blood Flow ◽  
Fractal Dimension ◽  
Gas Exchange ◽  
Spatial Correlation ◽  
Pulmonary Blood Flow ◽  
Minute Ventilation ◽  
Flow Distribution ◽  
Pulmonary Gas Exchange ◽  
Normal Lung ◽  
Blood Flow Distribution

Severe anemia is associated with remarkable stability of pulmonary gas exchange (S. Deem, M. K. Alberts, M. J. Bishop, A. Bidani, and E. R. Swenson. J. Appl. Physiol. 83: 240–246, 1997), although the factors that contribute to this stability have not been studied in detail. In the present study, 10 Flemish Giant rabbits were anesthetized, paralyzed, and mechanically ventilated at a fixed minute ventilation. Serial hemodilution was performed in five rabbits by simultaneous withdrawal of blood and infusion of an equal volume of 6% hetastarch; five rabbits were followed over a comparable time. Ventilation-perfusion (V˙a/Q˙) relationships were studied by using the multiple inert-gas-elimination technique, and pulmonary blood flow distribution was assessed by using fluorescent microspheres. Expired nitric oxide (NO) was measured by chemiluminescence. Hemodilution resulted in a linear fall in hematocrit over time, from 30 ± 1.6 to 11 ± 1%. Anemia was associated with an increase in arterial [Formula: see text] in comparison with controls ( P < 0.01 between groups). The improvement in O2 exchange was associated with reducedV˙a/Q˙heterogeneity, a reduction in the fractal dimension of pulmonary blood flow ( P = 0.04), and a relative increase in the spatial correlation of pulmonary blood flow ( P = 0.04). Expired NO increased with anemia, whereas it remained stable in control animals ( P < 0.0001 between groups). Anemia results in improved gas exchange in the normal lung as a result of an improvement in overallV˙a/Q˙matching. In turn, this may be a result of favorable changes in pulmonary blood flow distribution, as assessed by the fractal dimension and spatial correlation of blood flow and as a result of increased NO availability.

scholarly journals Oxidative status in plasma, urine and saliva of girls with anorexia nervosa and healthy controls: a cross-sectional study

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Alexandra Gaál Kovalčíková ◽  
Ľubica Tichá ◽  
Katarína Šebeková ◽  
Peter Celec ◽  
Alžbeta Čagalová ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Anorexia Nervosa ◽  
Redox Homeostasis ◽  
Oxidative Status ◽  
Carbonyl Stress ◽  
Healthy Controls ◽  
Psychosomatic Disorder ◽  
Cross Sectional ◽  
Wide Range ◽  
Markers Of Oxidative Stress

Abstract Background Anorexia nervosa (AN) is a serious psychosomatic disorder with unclear pathomechanisms. Metabolic dysregulation is associated with disruption of redox homeostasis that might play a pivotal role in the development of AN. The aim of our study was to assess oxidative status and carbonyl stress in plasma, urine and saliva of patients with AN and healthy controls. Methods Plasma, spot urine, and saliva were collected from 111 girls with AN (aged from 10 to 18 years) and from 29 age-matched controls. Markers of oxidative stress and antioxidant status were measured using spectrophotometric and fluorometric methods. Results Plasma advanced oxidation protein products (AOPP) and advanced glycation end products (AGEs) were significantly higher in patients with AN than in healthy controls (by 96, and 82%, respectively). Accordingly, urinary concentrations of AOPP and fructosamines and salivary concentrations of AGEs were higher in girls with AN compared with controls (by 250, and 41% in urine; by 92% in saliva, respectively). Concentrations of thiobarbituric acid reactive substances (TBARS) in saliva were 3-times higher in the patients with AN than in the controls. Overall antioxidants were lower in plasma of girls with AN compared to the controls, as shown by total antioxidant capacity and ratio of reduced and oxidized glutathione (by 43, and 31%, respectively). Conclusions This is the first study assessing wide range of markers of oxidative status in plasma, urine and saliva of the patients with AN. We showed that both, higher levels of markers of oxidative stress and lower antioxidants play a role in redox disruption. Restoration of redox homeostasis might be of the clinical relevance

scholarly journals Choroidal vascularity index in thyroid-associated ophthalmopathy: a cross-sectional study

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Pasquale Loiudice ◽  
Marco Pellegrini ◽  
Michele Marinò ◽  
Barbara Mazzi ◽  
Ilaria Ionni ◽  
...  
Keyword(s):  
Cross Sectional Study ◽  
Activity Score ◽  
Enhanced Depth Imaging ◽  
Clinical Activity ◽  
Healthy Controls ◽  
Cross Sectional ◽  
Clinical Activity Score ◽  
Significant Difference ◽  
Thyroid Associated Ophthalmopathy ◽  
Imagej Software

Abstract Background Hemodynamic changes have been observed in patients with Graves’ disease. The aim of our study was to evaluate choroidal vascular change using the choroidal vascularity index (CVI) in patients with thyroid-associated ophthalmopathy (TAO). Methods In this cross-sectional observational study, 40 patients affected by TAO were recruited. Forty healthy individuals, matched for age and sex, served as controls. Foveal enhanced-depth imaging optical coherence tomography scans were obtained from all participants. Images were binarized using the ImageJ software and luminal area (LA) and total choroidal area (TCA) were measured. CVI was calculated as the proportion of LA to TCA. The relation between CVI or subfoveal choroidal thickness (SFCT) and clinical activity score, exophthalmometric value, diplopia status, gender, and age was evaluated. Results CVI was significantly higher in patients with TAO (P = 0.004). No significant difference was observed in SFCT (P = 0.200) and TCA (P = 0.153) comparing TAO patients and healthy controls. LA was significantly higher in TAO group (P = 0.045). On multiple regression analysis, CVI was associated with TCA (P = 0.043). No association was found between SFCT or CVI and TCA, clinical activity score, exophthalmometric value, Inami value, diplopia status, gender or age (P > 0.05). Conclusions This is the first study that has demonstrated an increase in CVI in eyes with TAO compared with healthy controls and has assessed its association with clinical features.

scholarly journals Cross-sectional analysis of follow-up chest MRI and chest CT scans in patients previously affected by COVID-19

2021 ◽  
Author(s):  
Martina Pecoraro ◽  
Stefano Cipollari ◽  
Livia Marchitelli ◽  
Emanuele Messina ◽  
Maurizio Del Monte ◽  
...  
Keyword(s):  
Chest Ct ◽  
Ct Scans ◽  
Imaging Biomarker ◽  
Cross Sectional ◽  
Mri Scans ◽  
Magnetic Resonance Imaging Mri ◽  
Sectional Analysis ◽  
Ct And Mri ◽  
Interlobular Septal Thickening

Abstract Purpose The aim of the study was to prospectively evaluate the agreement between chest magnetic resonance imaging (MRI) and computed tomography (CT) and to assess the diagnostic performance of chest MRI relative to that of CT during the follow-up of patients recovered from coronavirus disease 2019. Materials and methods Fifty-two patients underwent both follow-up chest CT and MRI scans, evaluated for ground-glass opacities (GGOs), consolidation, interlobular septal thickening, fibrosis, pleural indentation, vessel enlargement, bronchiolar ectasia, and changes compared to prior CT scans. DWI/ADC was evaluated for signal abnormalities suspicious for inflammation. Agreement between CT and MRI was assessed with Cohen’s k and weighted k. Measures of diagnostic accuracy of MRI were calculated. Results The agreement between CT and MRI was almost perfect for consolidation (k = 1.00) and change from prior CT (k = 0.857); substantial for predominant pattern (k = 0.764) and interlobular septal thickening (k = 0.734); and poor for GGOs (k = 0.339), fibrosis (k = 0.224), pleural indentation (k = 0.231), and vessel enlargement (k = 0.339). Meanwhile, the sensitivity of MRI was high for GGOs (1.00), interlobular septal thickening (1.00), and consolidation (1.00) but poor for fibrotic changes (0.18), pleural indentation (0.23), and vessel enlargement (0.50) and the specificity was overall high. DWI was positive in 46.0% of cases. Conclusions The agreement between MRI and CT was overall good. MRI was very sensitive for GGOs, consolidation and interlobular septal thickening and overall specific for most findings. DWI could be a reputable imaging biomarker of inflammatory activity.

scholarly journals AB0709 CHARACTERIZATION OF NAILFOLD CAPILLAROSCOPY IN COVID-19: A CASE CONTROL STUDY

2021 ◽  
Vol 80 (Suppl 1) ◽  
pp. 1386.2-1387
Author(s):  
P. E. Bermudez Bermejo ◽  
R. Jimenez-Soto ◽  
A. Sanchez Rodríguez ◽  
A. Turrent ◽  
D. Mercado Velasco ◽  
...  
Keyword(s):  
Rheumatic Diseases ◽  
Medical Center ◽  
Microvascular Complications ◽  
Care Center ◽  
Invasive Mechanical Ventilation ◽  
Nailfold Capillaroscopy ◽  
Healthy Population ◽  
Healthy Controls ◽  
Clinical Tool ◽  
Cross Sectional

Background:Nailfold capillaroscopy is a relatively easy-to-access, low-cost clinical tool that could help identify early coagulopathy in subjects with SARS-CoV-2, but specific findings vs. controls and its possible prognostic role has not been studied.Objectives:To describe capillaroscopic findings and their usefulness in patients with COVID-19 compared to healthy controls.Methods:We designed a cross-sectional study, carried out in a single care center for critical patients with SARS-CoV-2 pneumonia at the ABC Medical Center, Mexico City, which included patients from an intensive care unit (ICU) and internal medicine ward from March to April 2020. Demographic, biochemical and clinical features were collected. All patients signed the informed consent and the study was approved by the hospital ethics committee. All patients underwent nail capillary imaging of the 3 central fingers of each hand with a portable microscope with 60-100x magnification coupled to a smartphone with 7 megapixel images in an immersion medium. Capillaroscopy was performed in patients who did not have fever or hypothermia, or need vasopressors at the time of evaluation. Control subjects are healthy subjects matched on age and sex from a database of healthy controls without rheumatic diseases. Image evaluation of COVID-19 patients was performed in a blinded way for their characteristics. Prior to the analysis of the images, a pilot test was obtained with 4 rheumatologists in random cases, obtaining an acceptable global agreement in the visualization of capillaries and specific alterations of the nail bed. (Kappa = 0.58, p = 0.0019). Obtained data from capillaroscopies were used to be compared between severe and moderate cases of SARS-CoV-2 pneumonia. Additionally, we compared the findings against a healthy population in order to establish a reference.Results:We included data from 27 patients and 32 controls with similar demographic features. Patients with COVID-19 patients had a mean age of 43 +/- 13.8 years, 63% female. Comorbidities were present in 44.4% with: type II Diabetes Mellitus 18.5%, systemic arterial hypertension 18.5%, and rheumatoid arthritis 3.7%. The mean length of stay time was 13 +/- 7.1 days, 48.1% were admitted to the ICU, and 40.7% required invasive mechanical ventilation. In the capillaroscopic review remarkable findings of patients vs. controls were hemosiderin deposits (33 vs 12.5%, p=0.05), less frequently observable capillaries (77 vs 100%, p=0.005), any abnormality in capillaries (25.9 vs. 6.3%, p=0.03). Of notice, specific findings in COVID-19 patients were capillary tortuosities in 19%, dilatation in 9.5%, serpentine pattern in 4.8%, bush pattern in 9.5% and decreased density in only 4.8% of the cases. No avascular areas or capillaries of neoformation were observed. Finally, the presence of hemosiderin was associated with worse presentation and risk factors for severe COVID-19: Male sex 66.7 vs. 27.8%, (p = 0.024); Admission to ICU 77% vs 33% (p = 0.029); BMI > 30 kg/m2 66.7 vs. 27.8% (p = 0.053). And risk for ICU admission OR = 7.0 (95% CI 1.098 - 44.6). No significant associations were found for abnormalities in capillary morphology.Conclusion:We present one of the first reports of nailfold capillaroscopic findings in patients with COVID-19 and the first to compare to healthy controls. Previous data on this regard suggests the presence of endothelial dysfunction and microvascular complications such as micro hemorrhage or micro thrombosis. Further studies may confirm these findings and prognostic value for worse outcomes in COVID-19 patients.References:[1]Chen N, Zhou M, Dong X, et al. Epidemiological and clinical characteristics of 99 cases of 2019 novel coronavirus pneumonia in Wuhan, China: a descriptive study. Lancet. 2020;395:507–13.[2]Cutolo M, Cortes S. capillaroscopic patterns in rheumatic diseases. Acta Reumatol Port. 2007 Jan-Mar;32(1):29-36.[3]Natalello G, De Luca G, Gigante L, et al. Nailfold capillaroscopy findings in patients with coronavirus disease 2019: Broadening the spectrum of COVID-19 microvascular involvement. Microvasc Res. 2021;133:104071.Disclosure of Interests:None declared

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