Determinants of maximal expiratory flow from the lungs.

Pride, N. B.; Permutt, Solbert; Riley, Richard L.; Bromberger-Barnea, B.

doi:10.1152/jappl.1967.23.5.646

Cited by 341 publications

(159 citation statements)

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“…This hypothesis is compatible with the observation that branching of the bronchial tree is complete by 16 weeks of gestation (21), and that the number of terminal bronchiolar duct endings does not increase postnatally (22). It should also be noted that elastic recoil plays a key role in determining maximal expiratory flow (23,24), not only because it is the motive force behind flow, but also because of its role in maintaining airway patency. Unfortunately, we did not measure static recoil in this epidemiologic study because of the invasive nature of its measurement.…”

Section: Discussionsupporting

confidence: 84%

Poor airway function in early infancy and lung function by age 22 years: a non-selective longitudinal cohort study

et al. 2007

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Section: Discussionsupporting

confidence: 84%

Poor airway function in early infancy and lung function by age 22 years: a non-selective longitudinal cohort study

et al. 2007

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“…The three classic determinants of expiratory flow limitation are lung elastic recoil, the propensity for airways to close, and airway resistance (5). Loss of elastic recoil in emphysema decreases the upstream pressure that drives expiratory flow, thereby decreasing maximal flows at any lung volume.…”

Section: Effects Of Emphysema On Expiratory Flowmentioning

confidence: 99%

Physiologic Basis for Improved Pulmonary Function after Lung Volume Reduction

Fessler¹,

Scharf²,

Ingenito³

et al. 2008

Proceedings of the American Thoracic Society

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It is not readily apparent how pulmonary function could be improved by resecting portions of the lung in patients with emphysema. In emphysema, elevation in residual volume relative to total lung capacity reduces forced expiratory volumes, increases inspiratory effort, and impairs inspiratory muscle mechanics. Lung volume reduction surgery (LVRS) better matches the size of the lungs to the size of the thorax containing them. This restores forced expiratory volumes and the mechanical advantage of the inspiratory muscles. In patients with heterogeneous emphysema, LVRS may also allow space occupied by cysts to be reclaimed by more normal lung. Newer, bronchoscopic methods for lung volume reduction seek to achieve similar ends by causing localized atelectasis, but may be hindered by the low collateral resistance of emphysematous lung. Understanding of the mechanisms of improved function after LVRS can help select patients more likely to benefit from this approach.Keywords: lung mechanics; emphysema surgery; lung recoil; airflow limitation; respiratory muscles PHYSIOLOGIC BASIS FOR IMPAIRMENT WITH EMPHYSEMAInflammatory changes associated with chronic obstructive pulmonary disease (COPD) initiate the changes in lung mechanical properties that characterize emphysema. Inflammation leads to destruction of elastin, which contributes to lung elasticity, and collagen, which provides tensile strength. Although recent interest has focused on the cellular and molecular mechanisms contributing to emphysema, the study of lung mechanical stresses, one of the earliest postulated causes of emphysema (1), has received less attention. Weakened lung parenchyma is more likely to fracture during respiratory stress, and coalescence of a few alveoli can increase stress on adjacent units in a way that favors formation of large, localized cysts similar to the pattern seen in patients with advanced emphysema (2-4). Effects of Emphysema on Expiratory FlowThese sequelae of inflammation ultimately decrease lung elastic recoil and small airway caliber, contributing to characteristic airflow limitation. The three classic determinants of expiratory flow limitation are lung elastic recoil, the propensity for airways to close, and airway resistance (5). Loss of elastic recoil in emphysema decreases the upstream pressure that drives expiratory flow, thereby decreasing maximal flows at any lung volume. Loss of elastic recoil also increases the unstressed volume of the lung (the volume remaining when elastic recoil is zero). Loss of radial traction on airways from lung parenchyma contributes to airway closure at higher lung volumes (increased trapped volume) because a higher transmural pressure is required to maintain airway patency. In addition, airway caliber at any lung volume is decreased (6). Coexisting small airway inflammation and fibrosis further increase airway resistance (7,8). These changes collectively reduce the rate of lung emptying.The rate of lung emptying may be expressed as its time constant, the time necessary for approximately 63% o...

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“…When the pressure in the chamber increases above the pressure inside the tube, this becomes narrowed increasing the resistance to flow. The increased driving pressure meets with increased resistance and therefore above certain limits the flow cannot be further increased (Pride et at., 1967).…”

Section: Introductionmentioning

confidence: 99%

The flow-volume loop in tetraplegics

1977

Spinal Cord

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Determinants of maximal expiratory flow from the lungs.

Cited by 341 publications

References 0 publications

Poor airway function in early infancy and lung function by age 22 years: a non-selective longitudinal cohort study

Poor airway function in early infancy and lung function by age 22 years: a non-selective longitudinal cohort study

Physiologic Basis for Improved Pulmonary Function after Lung Volume Reduction

The flow-volume loop in tetraplegics

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