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.

Nitric oxide and cardiopulmonary hemodynamics in Tibetan highlanders

2005 ◽  
Vol 99 (5) ◽  
pp. 1796-1801 ◽  
Author(s):  
Brian D. Hoit ◽  
Nancy D. Dalton ◽  
Serpil C. Erzurum ◽  
Daniel Laskowski ◽  
Kingman P. Strohl ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Blood Flow ◽  
Pulmonary Artery ◽  
High Altitude ◽  
Sea Level ◽  
Pulmonary Blood Flow ◽  
Geometric Mean ◽  
Systolic Pressure ◽  
Pulmonary Artery Systolic Pressure ◽  
Exhaled No

When O2 availability is reduced unavoidably, as it is at high altitude, a potential mechanism to improve O2 delivery to tissues is an increase in blood flow. Nitric oxide (NO) regulates blood vessel diameter and can influence blood flow. This field study of intrapopulation variation at high altitude tested the hypothesis that the level of exhaled NO (a summary measure of pulmonary synthesis, consumption, and transfer from cells in the airway) is directly proportional to pulmonary, and thus systemic, blood flow. Twenty Tibetan male and 37 female healthy, nonsmoking, native residents at 4,200 m (13,900 ft), with an average O2 saturation of hemoglobin of 85%, participated in the study. The geometric mean partial pressure of NO exhaled at a flow of 17 ml/s was 23.4 nmHg, significantly lower than that of a sea-level reference group. However, the rate of NO transfer out of the airway wall was seven times higher than at sea level, which implied the potential for vasodilation of the pulmonary blood vessels. Mean pulmonary blood flow (measured by cardiac index) was 2.7 ± 0.1 (SE) l/min, and mean pulmonary artery systolic pressure was 31.4 ± 0.9 (SE) mmHg. Higher exhaled NO was associated with higher pulmonary blood flow; yet there was no associated increase in pulmonary artery systolic pressure. The results suggest that NO in the lung may play a key beneficial role in allowing Tibetans at 4,200 m to compensate for ambient hypoxia with higher pulmonary blood flow and O2 delivery without the consequences of higher pulmonary arterial pressure.

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.

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.

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