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Martin Ugander - One of the best experts on this subject based on the ideXlab platform.
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Supine, prone, right and left gravitational effects on human pulmonary circulation
Journal of Cardiovascular Magnetic Resonance, 2019Co-Authors: Björn Wieslander, Joao Génio Ramos, Johan Petersson, Martin UganderAbstract:Background Body position can be optimized for pulmonary ventilation/perfusion matching during surgery and intensive care. However, positional effects upon distribution of pulmonary Blood flow and vascular distensibility measured as the pulmonary Blood Volume variation have not been quantitatively characterized. In order to explore the potential clinical utility of body position as a modulator of pulmonary hemodynamics, we aimed to characterize gravitational effects upon distribution of pulmonary Blood flow, pulmonary vascular distension, and pulmonary vascular distensibility. Methods Healthy subjects ( n = 10) underwent phase contrast cardiovascular magnetic resonance (CMR) pulmonary artery and vein flow measurements in the supine, prone, and right/left lateral decubitus positions. For each Lung, Blood Volume variation was calculated by subtracting venous from arterial flow per time frame. Results Body position did not change cardiac output ( p = 0.84). There was no difference in Blood flow between the superior and inferior pulmonary veins in the supine ( p = 0.92) or prone body positions ( p = 0.43). Compared to supine, pulmonary Blood flow increased to the dependent Lung in the lateral positions (16–33%, p = 0.002 for both). Venous but not arterial cross-sectional vessel area increased in both Lungs when dependent compared to when non-dependent in the lateral positions (22–27%, p ≤ 0.01 for both). In contrast, compared to supine, distensibility increased in the non-dependent Lung in the lateral positions (68–113%, p = 0.002 for both). Conclusions CMR demonstrates that in the lateral position, there is a shift in Blood flow distribution, and venous but not arterial Blood Volume, from the non-dependent to the dependent Lung. The non-dependent Lung has a sizable pulmonary vascular distensibility reserve, possibly related to left atrial pressure. These results support the physiological basis for positioning patients with unilateral pulmonary pathology with the “good Lung down” in the context of intensive care. Future studies are warranted to evaluate the diagnostic potential of these physiological insights into pulmonary hemodynamics, particularly in the context of non-invasively characterizing pulmonary hypertension.
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Supine, prone, right and left gravitational effects on human pulmonary circulation
Journal of cardiovascular magnetic resonance : official journal of the Society for Cardiovascular Magnetic Resonance, 2019Co-Authors: Björn Wieslander, Joao Génio Ramos, Johan Petersson, Martin UganderAbstract:Body position can be optimized for pulmonary ventilation/perfusion matching during surgery and intensive care. However, positional effects upon distribution of pulmonary Blood flow and vascular distensibility measured as the pulmonary Blood Volume variation have not been quantitatively characterized. In order to explore the potential clinical utility of body position as a modulator of pulmonary hemodynamics, we aimed to characterize gravitational effects upon distribution of pulmonary Blood flow, pulmonary vascular distension, and pulmonary vascular distensibility. Healthy subjects (n = 10) underwent phase contrast cardiovascular magnetic resonance (CMR) pulmonary artery and vein flow measurements in the supine, prone, and right/left lateral decubitus positions. For each Lung, Blood Volume variation was calculated by subtracting venous from arterial flow per time frame. Body position did not change cardiac output (p = 0.84). There was no difference in Blood flow between the superior and inferior pulmonary veins in the supine (p = 0.92) or prone body positions (p = 0.43). Compared to supine, pulmonary Blood flow increased to the dependent Lung in the lateral positions (16–33%, p = 0.002 for both). Venous but not arterial cross-sectional vessel area increased in both Lungs when dependent compared to when non-dependent in the lateral positions (22–27%, p ≤ 0.01 for both). In contrast, compared to supine, distensibility increased in the non-dependent Lung in the lateral positions (68–113%, p = 0.002 for both). CMR demonstrates that in the lateral position, there is a shift in Blood flow distribution, and venous but not arterial Blood Volume, from the non-dependent to the dependent Lung. The non-dependent Lung has a sizable pulmonary vascular distensibility reserve, possibly related to left atrial pressure. These results support the physiological basis for positioning patients with unilateral pulmonary pathology with the “good Lung down” in the context of intensive care. Future studies are warranted to evaluate the diagnostic potential of these physiological insights into pulmonary hemodynamics, particularly in the context of non-invasively characterizing pulmonary hypertension.
J. Peters - One of the best experts on this subject based on the ideXlab platform.
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Interaction between haematocrit and pulmonary Blood Volume on pulmonary vascular flow resistance and pressure-flow relationships
Intensive Care Medicine, 1997Co-Authors: S. A. Loer, T. W. L. Scheeren, J. PetersAbstract:Objective: Pulmonary vascular flow resistance depends on Blood viscosity, mainly due to haematocrit, and on vessel dimensions determining Blood Volume in this highly compliant vascular bed. We, therefore, evaluated the interaction between haematocrit, Blood flow, and transpulmonary vascular pressure gradient under conditions of controlled pulmonary Blood Volume. Design: Experimental study in isolated zone-III rabbit Lungs perfused with autologous Blood. Setting: Laboratory for experimental studies. Interventions: Stepwise and independent variation of flow (50, 100, and 200 ml/min), pulmonary Blood Volume (increments of 2.5 ml and 5 ml imposed by changes of left atrial pressure), and haematocrit (0–50 %) varied by haemodilution (Krebs-Henseleit/albumin) or haemoconcentration (centrifugation). Measurements: Pulmonary arterial, left atrial, and airway pressures as well as reservoir Volume (reflecting reciprocal changes of Lung Blood Volume) and Lung weight. Results: Haemodilution from the normal haematocrit (32 %) to 10 % at constant pulmonary Blood Volume and flow decreased flow resistance only slightly, whereas haemoconcentration (50 %) increased flow resistance up to 130 %. At the same time increments of in pulmonary Blood Volume of 2.5 and 5 ml (approx. 15 and 30 % of normal pulmonary Blood Volume) at constant haematocrit significantly shifted downwards pressure-flow relationships for all investigated haematocrits (0–50 %). Conclusions: Because of the multiple interrelationships between haematocrit, Blood flow and pulmonary Blood Volume, haematocrit effects on pulmonary flow resistance and pressure-flow relationships in the pulmonary vasculature should be studied at controlled Blood Volume. While haemodilution only has minor effects, haemoconcentration changes pressure-flow relationships markedly. Pulmonary Blood Volume has a major impact on slope and position of pressure-flow relationships for all haematocrits investigated.
Björn Wieslander - One of the best experts on this subject based on the ideXlab platform.
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Supine, prone, right and left gravitational effects on human pulmonary circulation
Journal of Cardiovascular Magnetic Resonance, 2019Co-Authors: Björn Wieslander, Joao Génio Ramos, Johan Petersson, Martin UganderAbstract:Background Body position can be optimized for pulmonary ventilation/perfusion matching during surgery and intensive care. However, positional effects upon distribution of pulmonary Blood flow and vascular distensibility measured as the pulmonary Blood Volume variation have not been quantitatively characterized. In order to explore the potential clinical utility of body position as a modulator of pulmonary hemodynamics, we aimed to characterize gravitational effects upon distribution of pulmonary Blood flow, pulmonary vascular distension, and pulmonary vascular distensibility. Methods Healthy subjects ( n = 10) underwent phase contrast cardiovascular magnetic resonance (CMR) pulmonary artery and vein flow measurements in the supine, prone, and right/left lateral decubitus positions. For each Lung, Blood Volume variation was calculated by subtracting venous from arterial flow per time frame. Results Body position did not change cardiac output ( p = 0.84). There was no difference in Blood flow between the superior and inferior pulmonary veins in the supine ( p = 0.92) or prone body positions ( p = 0.43). Compared to supine, pulmonary Blood flow increased to the dependent Lung in the lateral positions (16–33%, p = 0.002 for both). Venous but not arterial cross-sectional vessel area increased in both Lungs when dependent compared to when non-dependent in the lateral positions (22–27%, p ≤ 0.01 for both). In contrast, compared to supine, distensibility increased in the non-dependent Lung in the lateral positions (68–113%, p = 0.002 for both). Conclusions CMR demonstrates that in the lateral position, there is a shift in Blood flow distribution, and venous but not arterial Blood Volume, from the non-dependent to the dependent Lung. The non-dependent Lung has a sizable pulmonary vascular distensibility reserve, possibly related to left atrial pressure. These results support the physiological basis for positioning patients with unilateral pulmonary pathology with the “good Lung down” in the context of intensive care. Future studies are warranted to evaluate the diagnostic potential of these physiological insights into pulmonary hemodynamics, particularly in the context of non-invasively characterizing pulmonary hypertension.
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Supine, prone, right and left gravitational effects on human pulmonary circulation
Journal of cardiovascular magnetic resonance : official journal of the Society for Cardiovascular Magnetic Resonance, 2019Co-Authors: Björn Wieslander, Joao Génio Ramos, Johan Petersson, Martin UganderAbstract:Body position can be optimized for pulmonary ventilation/perfusion matching during surgery and intensive care. However, positional effects upon distribution of pulmonary Blood flow and vascular distensibility measured as the pulmonary Blood Volume variation have not been quantitatively characterized. In order to explore the potential clinical utility of body position as a modulator of pulmonary hemodynamics, we aimed to characterize gravitational effects upon distribution of pulmonary Blood flow, pulmonary vascular distension, and pulmonary vascular distensibility. Healthy subjects (n = 10) underwent phase contrast cardiovascular magnetic resonance (CMR) pulmonary artery and vein flow measurements in the supine, prone, and right/left lateral decubitus positions. For each Lung, Blood Volume variation was calculated by subtracting venous from arterial flow per time frame. Body position did not change cardiac output (p = 0.84). There was no difference in Blood flow between the superior and inferior pulmonary veins in the supine (p = 0.92) or prone body positions (p = 0.43). Compared to supine, pulmonary Blood flow increased to the dependent Lung in the lateral positions (16–33%, p = 0.002 for both). Venous but not arterial cross-sectional vessel area increased in both Lungs when dependent compared to when non-dependent in the lateral positions (22–27%, p ≤ 0.01 for both). In contrast, compared to supine, distensibility increased in the non-dependent Lung in the lateral positions (68–113%, p = 0.002 for both). CMR demonstrates that in the lateral position, there is a shift in Blood flow distribution, and venous but not arterial Blood Volume, from the non-dependent to the dependent Lung. The non-dependent Lung has a sizable pulmonary vascular distensibility reserve, possibly related to left atrial pressure. These results support the physiological basis for positioning patients with unilateral pulmonary pathology with the “good Lung down” in the context of intensive care. Future studies are warranted to evaluate the diagnostic potential of these physiological insights into pulmonary hemodynamics, particularly in the context of non-invasively characterizing pulmonary hypertension.
Roberto Bianchi - One of the best experts on this subject based on the ideXlab platform.
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Simultaneous Recording of Blood Volume Shifts in Different Vascular Beds in Man by a Versatile Scintigraphic Method
Angiology, 1993Co-Authors: Baccelli G, Sergio Terrani, Paolo Pacenti, Ezio Omboni, Mario Bergonzi, Paolo Reggiani, Franco Sardella, Michele Catalano, Roberto BianchiAbstract:A device was developed to record the Blood Volume changes occurring in the Lung and calf during postural changes, physical exercise, and the Valsalva ma neuver in man.The changes in regional counting rates from the right middle Lung and the calf mirrored the well-known changes in venous return that are expected to occur in response to the above-mentioned external stimuli. Thus a sustained decrease in Lung Blood Volume was noted on assumption of the erect posture as well as during the forced expiration of the Valsalva maneuver. In addition a rapid increase and a sharp decrease in Lung Blood Volume took place at the very onset and at the very end of walking, respectively. The calf Blood Volume de clined immediately at the onset of walking, increased slightly in the ensuing two minutes, and returned to baseline quickly at the termination of walking.The authors' method enables real-time equilibrium Blood pool scintigraphy to be recorded continuously and simultaneously from different districts over sustained p...
Nora Ngai - One of the best experts on this subject based on the ideXlab platform.
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Abstract 15873: Adverse Cardiac and Pulmonary Vascular Change in Patients With Subclinical and Clinical Copd
Circulation, 2014Co-Authors: Jie Cao, Kathy Halloran, Joshua Cheng, Michael Passick, Nora NgaiAbstract:Background: COPD is associated with altered right ventricular (RV) and pulmonary vascular function. However, little is known about such change in patients with subclinical COPD. Methods: Thirty nine volunteers were recruited prospectively to undergo echocardiography, MRI and pulmonary function test (PFT). COPD was defined as FEV1/FVC 75% with no smoking history (N=9). Cardiac function was assessed by cine MRI. All subjects underwent first pass Lung perfusion using a partial Fourier saturation recovery SSFP technique. The absolute Lung perfusion was calculated using dynamic contrast signal in the pulmonary artery as input and that in the Lungs. Total Lung Blood Volume was the function of mean Blood transit time and cardiac output in main pulmonary artery (PA). Results: Average FEV1/FVC was 84±6%, 73±3% and 50±15% for normal, subclinical and clinical COPD groups, respectively (p Conclusions: Our findings suggest that the decline of cardiovascular function precedes the full development of COPD. Future research on pulmonary and cardiovascular change in patients with subclinical COPD is warranted.
