Quantitation of the Regional Distribution of Pulmonary Blood Flow by Fractal Analysis

1990 ◽  
pp. 196-200
Author(s):  
H. Thomas Robertson ◽  
Robb W. Glenny
Keyword(s):  
Blood Flow ◽  
Fractal Analysis ◽  
Pulmonary Blood Flow ◽  
Regional Distribution

Regional Distribution of Pulmonary Blood Flow in Normal High-Altitude Dwellers at 3,650 m (12,200 ft)

Respiration ◽  
1975 ◽  
Vol 32 (3) ◽  
pp. 189-209 ◽  
Author(s):  
J. Coudert ◽  
M. Paz-Zamora ◽  
L. Barragan ◽  
L. Briançon ◽  
H. Spielvogel ◽  
...  
Keyword(s):  
Blood Flow ◽  
High Altitude ◽  
Pulmonary Blood Flow ◽  
Regional Distribution

Influence of Anaesthesia on the Regional Distribution of Perfusion and Ventilation in the Lung

1970 ◽  
Vol 38 (4) ◽  
pp. 451-460 ◽  
Author(s):  
G. H. Hulands ◽  
R. Greene ◽  
L. D. Iliff ◽  
J. F. Nunn
Keyword(s):  
Blood Flow ◽  
Lung Volume ◽  
Pulmonary Blood Flow ◽  
Artificial Ventilation ◽  
Pulmonary Ventilation ◽  
Regional Distribution ◽  
Residual Capacity ◽  
Arterial Po2 ◽  
Ventilation And Perfusion ◽  
Perfusion Unit

1. Distribution of lung volume, pulmonary ventilation and perfusion were studied in supine patients before and during anaesthesia with paralysis and artificial ventilation. Inspired gas and pulmonary blood flow were measured with 133xenon and the chest was scanned with vertically moving counters at a lung volume of 1 litre above functional residual capacity. 2. Ventilation/unit lung volume was slightly greater and perfusion/unit lung volume substantially greater during anaesthesia in the dependent parts of the lungs. The spread of ventilation/perfusion ratios in supine conscious patients was small in comparison with that reported in upright conscious patients. During anaesthesia and artificial ventilation, the inequality of ventilation to perfusion was marginally increased in three of the four patients. 3. Ventilation/perfusion inequality alone was insufficient to explain the alveolar—arterial Po2 difference usually observed during anaesthesia.

Redistribution of pulmonary blood flow during unilateral hypoxia in prone and supine dogs

1998 ◽  
Vol 84 (6) ◽  
pp. 2010-2019 ◽  
Author(s):  
Christopher M. Mann ◽  
Karen B. Domino ◽  
Sten M. Walther ◽  
Robb W. Glenny ◽  
Nayak L. Polissar ◽  
...  
Keyword(s):  
Blood Flow ◽  
Pulmonary Blood Flow ◽  
Regional Distribution ◽  
Left Lung ◽  
Flow Distribution ◽  
Random Order ◽  
Total Flow ◽  
Hypoxic Vasoconstriction ◽  
Anesthetized Dogs ◽  
The Right

We used fluorescent-labeled microspheres in pentobarbital-anesthetized dogs to study the effects of unilateral alveolar hypoxia on the pulmonary blood flow distribution. The left lung was ventilated with inspired O2 fraction of 1.0, 0.09, or 0.03 in random order; the right lung was ventilated with inspired O2 fraction of 1.0. The lungs were removed, cleared of blood, dried at total lung capacity, then cubed to obtain ∼1,500 small pieces of lung (∼1.7 cm3). The coefficient of variation of flow increased ( P < 0.001) in the hypoxic lung but was unchanged in the hyperoxic lung. Most (70–80%) variance in flow in the hyperoxic lung was attributable to structure, in contrast to only 30–40% of the variance in flow in the hypoxic lung ( P < 0.001). When adjusted for the change in total flow to each lung, 90–95% of the variance in the hyperoxic lung was attributable to structure compared with 70–80% in the hypoxic lung ( P < 0.001). The hilar-to-peripheral gradient, adjusted for change in total flow, decreased in the hypoxic lung ( P = 0.005) but did not change in the hyperoxic lung. We conclude that hypoxic vasoconstriction alters the regional distribution of flow in the hypoxic, but not in the hyperoxic, lung.

scholarly journals Measurement of pulmonary blood flow by fractal analysis of flow heterogeneity in isolated canine lungs

1996 ◽  
Vol 81 (5) ◽  
pp. 2039-2045 ◽  
Author(s):  
Scott A. Barman ◽  
Laryssa L. McCloud ◽  
John D. Catravas ◽  
Ina C. Ehrhart
Keyword(s):  
Blood Flow ◽  
Fractal Dimension ◽  
Fractal Analysis ◽  
Pulmonary Blood Flow ◽  
Flow Distribution ◽  
Blood Flow Rate ◽  
Blood Flow Distribution ◽  
Flow Rates ◽  
Flow Heterogeneity ◽  
Lung Lobes

Barman, Scott A., Laryssa L. McCloud, John D. Catravas, and Ina C. Ehrhart. Measurement of pulmonary blood flow by fractal analysis of flow heterogeneity in isolated canine lungs. J. Appl. Physiol. 81(5): 2039–2045, 1996.—Regional heterogeneity of lung blood flow can be measured by analyzing the relative dispersion (RD) of mass (weight)-flow data. Numerous studies have shown that pulmonary blood flow is fractal in nature, a phenomenon that can be characterized by the fractal dimension and the RD for the smallest realizable volume element (piece size). Although information exists for the applicability of fractal analysis to pulmonary blood flow in whole animal models, little is known in isolated organs. Therefore, the present study was done to determine the effect of blood flow rate on the distribution of pulmonary blood flow in the isolated blood-perfused canine lung lobe by using fractal analysis. Four different radiolabeled microspheres (141Ce,95Nb,85Sr, and51Cr), each 15 μm in diameter, were injected into the pulmonary lobar artery of isolated canine lung lobes ( n = 5) perfused at four different flow rates ( flow 1 = 0.42 ± 0.02 l/min; flow 2 = 1.12 ± 0.07 l/min; flow 3 = 2.25 ± 0.17 l/min; flow 4 = 2.59 ± 0.17 l/min), and the pulmonary blood flow distribution was measured. The results of the present study indicate that under isogravimetric blood flow conditions, all regions of horizontally perfused isolated lung lobes received blood flow that was preferentially distributed to the most distal caudal regions of the lobe. Regional pulmonary blood flow in the isolated perfused canine lobe was heterogeneous and fractal in nature, as measured by the RD. As flow rates increased, fractal dimension values (averaging 1.22 ± 0.08) remained constant, whereas RD decreased, reflecting more homogeneous blood flow distribution. At any given blood flow rate, high-flow areas of the lobe received a proportionally larger amount of regional flow, suggesting that the degree of pulmonary vascular recruitment may also be spatially related.

Pulmonary perfusion is more uniform in the prone than in the supine position: scintigraphy in healthy humans

1999 ◽  
Vol 86 (4) ◽  
pp. 1135-1141 ◽  
Author(s):  
Sven Nyrén ◽  
Margareta Mure ◽  
Hans Jacobsson ◽  
Stig A. Larsson ◽  
Sten G. E. Lindahl
Keyword(s):  
Blood Flow ◽  
Supine Position ◽  
Pulmonary Blood Flow ◽  
Single Photon ◽  
Regional Distribution ◽  
Photon Emission ◽  
Flow Distribution ◽  
Lung Perfusion ◽  
Emission Computed Tomography ◽  
Healthy Humans

The main purpose of this study was to find out whether the dominant dorsal lung perfusion while supine changes to a dominant ventral lung perfusion while prone. Regional distribution of pulmonary blood flow was determined in 10 healthy volunteers. The subjects were studied in both prone and supine positions with and without lung distension caused by 10 cmH2O of continuous positive airway pressure (CPAP). Radiolabeled macroaggregates of albumin, rapidly trapped by pulmonary capillaries in proportion to blood flow, were injected intravenously. Tomographic gamma camera examinations (single-photon-emission computed tomography) were performed after injections in the different positions. All data acquisitions were made with the subject in the supine position. CPAP enhanced perfusion differences along the gravitational axis, which was more pronounced in the supine than prone position. Diaphragmatic sections of the lung had a more uniform pulmonary blood flow distribution in the prone than supine position during both normal and CPAP breathing. It was concluded that the dominant dorsal lung perfusion observed when the subjects were supine was not changed into a dominant ventral lung perfusion when the subjects were prone. Lung perfusion was more uniformly distributed in the prone compared with in the supine position, a difference that was more marked during total lung distension (CPAP) than during normal breathing.

Regional trapping of microspheres in the lung compares well with regional blood flow

1987 ◽  
Vol 63 (2) ◽  
pp. 883-889 ◽  
Author(s):  
K. C. Beck
Keyword(s):  
Blood Flow ◽  
Pulmonary Blood Flow ◽  
Gamma Camera ◽  
Regional Blood Flow ◽  
Regional Distribution ◽  
Regions Of Interest ◽  
Rapid Imaging ◽  
Arterial Perfusion ◽  
Regional Flow ◽  
Slow Injection

Microspheres (MS) are often used to measure the distribution of pulmonary blood flow in the assumption that the number of MS trapped in a region is proportional to blood flow. However, regional distribution of trapped MS has not been directly compared with regional blood flow in the lung. Regional trapping of MS was compared with regional flow of erythrocytes (RBC's) in isolated, perfused left lungs of dogs. Radioactivity from labeled MS and RBC's was measured by external detection using a gamma camera. We defined six regions of interest in the image of the left lateral surface of the lung: a dorsocaudal, a caudal, two ventral, an apical, and a central region. In each lung, regional trapping of MS was measured from the image of radioactivity obtained after slow injection of a suspension of MS into the arterial perfusion tubing. A radioactive bolus of labeled RBC's was injected during rapid imaging of the lung to obtain radioactivity vs. time curves from each region. The peaks of the regional radioactivity vs. time curves were used to estimate regional flows, though compensation had to be made for overlap of the washout and washin phases of the bolus of labeled RBC's. The results indicated that there were no differences in the regional distribution of MS compared with the regional distribution of RBC flow in isolated, perfused dog lungs.

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