Factors affecting regional distribution of ventilation and perfusion in the lung

Bryan, A. C.; Bentivoglio, Lamberto G.; Beerel, Frederick R.; Macleish, H.; Zidulka, A.; Bates, David V.

doi:10.1152/jappl.1964.19.3.395

Cited by 215 publications

(52 citation statements)

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“…Experimental data of the regional lung expansion at normal gravity (1G) show a preferential distribution of inspired gas to the lower regions of the lung if inspired slowly (Ball et al 1962;Bryan et al 1964;Milic-Emili et al 1966;Sutherland et al 1968). This is caused by the fact that the lower regions are more compliant than the upper ones due to the difference in pleural pressure.…”

Section: Introductionmentioning

confidence: 99%

A Model of Ventilation Distribution in the Human Lung

Chang

Yu²

1999

Aerosol Science and Technology

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A thorough analysis of aerosol particle deposition in the human lung requires the knowledge of the distribution of inspired air at respiration. In this paper, a mathematical model of ventilation distribution has been developed using a five-lobe airway model. The model accounts for the nonlinear effects of compliance and resistance on airway dynamics. Ventilation distributions were determined under different gravitational force conditions. A larger gravity leads to a greater nonuniformity of ventilation between the upper and lower lobes of the lung. Ventilation distributions in different lobes of the lung at various inspiratory flow rates were also calculated. At slow inspiratory flow rates, ventilation was found to be nonuniform with more air entering the lower lobes. As the flow rate increases, this nonuniformity became smaller. The calculated results compare favorably with existing experimental data. When a different gas is inspired instead of air, a preferential distribution of ventilation to the upper lobes was found if the density of the inspired gas is greater than that of the air.

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Section: Introductionmentioning

confidence: 99%

A Model of Ventilation Distribution in the Human Lung

Chang

Yu²

1999

Aerosol Science and Technology

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“…Pulmonary blood flow can clear material from the alveoli and the intersititial space, and its effects are gravity dependent (16). Bronchial blood flow can clear some of the ions deposited in central and peri pheral airways.…”

Section: Discussionmentioning

confidence: 99%

Regional Clearance of Ions from the Airways of the Lung^1–³

Yeates¹,

Aspin²,

Bryan³

et al. 1973

Am Rev Respir Dis

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_To understand the physiologic mechanisms of lung clearance and how soluble substances such as those deposited in the lung by inhalation therapy or air pollution are cleared, experiments were performed on 3 normal men to show clearance of the pertechnetate ion from 12 regions of the right lung. Each subject, seated in front of a gamma camera, inhaled 2 ml of 0.156 M sodium chloride mist containing 300 p'c of sodium pertechnetate of .approximately 5 p. mass median diameter. The clearance was followed for 5 hours by measuring regional count rates over the lung with a gamma camera, while activity in the blood was monitored by a scintillation probe over the thigh. To correct for radioactivity in the blood in the chest, an intravenous injection of 70 p'c sodium pertechnetate in saline, given at another time, was monitored with the gamma camera and the thigh probe. Each clearance study was repeated with the subject in the supine position; the aerosol was alw.ays inhaled in the upright position.In the supine position, clearance half-times were uniform over the entire lung and ranged from 7 to 13 minutes ,in different subjects. Similar clearance times over the lower lung were found in the upright position; however, clearance half-times became longer near the apex. This suggests that the clearance of ions from the apex is affected by the reduced blood flow to this region. Pulmonary and bronchial blood flows appear to be the major mechanisms for the clearance of ions from the airways.

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“…The review materials are abstracted from original seminal publications and text books of lung physiology with particular recognition of the original work by West, Bryan and Milic-Emili [1][2][3]. These materials are supported by selected references obtained from a PubMed literature search that included title terms ''ventilation heterogeneity'' and ''asthma''.…”

Section: Data Sourcesmentioning

confidence: 99%

Ventilation heterogeneity in asthma

Teague¹,

Tustison

Altes

2014

Journal of Asthma

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Non-uniform distribution of inspired gas within the lung, termed ventilation heterogeneity, is present in patients with even mild asthma. Current evidence strongly supports ventilation heterogeneity as a fundamental derangement of lung function in asthma that contributes per se to hypoxemia and airway hyper-responsiveness. An extreme example of ventilation heterogeneity is the identification by hyperpolarized gas MRI of lung regions with no ventilation, termed filling defects. Lung filling defects in patients with asthma can persist over time, increase in size with methacholine-induced bronchospasm and more likely are caused by obstruction of the peripheral and not the proximal airways. Ventilation heterogeneity can be quantified in the conducting and acinar lung zones with the multiple gas washout method, and in the acinar zone does not fully resolve following bronchodilator treatment in patients with asthma. In prospective studies, the degree of ventilation heterogeneity at baseline predicts airway hyper-responsiveness and response to corticosteroid dose titration. An important unanswered question is the relationship of airways inflammation to ventilation heterogeneity. In consideration of the importance of ventilation heterogeneity in its pathobiology, asthma is more a focal disorder with regional pathology akin to regional ileitis and not the generalized disorder of the airways as it has been viewed in the past.

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Factors affecting regional distribution of ventilation and perfusion in the lung

Cited by 215 publications

References 0 publications

A Model of Ventilation Distribution in the Human Lung

A Model of Ventilation Distribution in the Human Lung

Regional Clearance of Ions from the Airways of the Lung^1–³

Ventilation heterogeneity in asthma

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Factors affecting regional distribution of ventilation and perfusion in the lung

Cited by 215 publications

References 0 publications

A Model of Ventilation Distribution in the Human Lung

A Model of Ventilation Distribution in the Human Lung

Regional Clearance of Ions from the Airways of the Lung1–3

Ventilation heterogeneity in asthma

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Regional Clearance of Ions from the Airways of the Lung^1–³