Mechanical Properties of the Lung

Bates, Jason H. T.

doi:10.1016/b978-0-12-404577-4.00016-3

Cited by 9 publications

(5 citation statements)

References 92 publications

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“…Under physiological conditions, the contribution of the individual compartments to the total respiratory mechanics depends on lung expansion (8 -10, 13, 14, 16, 17, 21, 29) and the tone of the chest wall musculature (35). Based on earlier findings, it can also be anticipated that the size of the species also affects the contribution of the chest wall to total respiratory system mechanics, with chest wall contribution tending to increase in larger mammals (2,4). Nevertheless, speciesdependent contributions from lungs and chest wall to respiratory mechanics have not been evaluated systematically.…”

Section: Introductionmentioning

confidence: 94%

Different contributions from lungs and chest wall to respiratory mechanics in mice, rats, and rabbits

Südy

Fodor

Rocha

et al. 2019

Journal of Applied Physiology

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Changes in lung mechanics are frequently inferred from intact-chest measures of total respiratory system mechanics without consideration of the chest wall contribution. The participation of lungs and chest wall in respiratory mechanics has not been evaluated systematically in small animals commonly used in respiratory research. Thus, we compared these contributions in intact-chest mice, rats, and rabbits and further characterized the influence of positive end-expiratory pressure (PEEP). Forced oscillation technique was applied to anesthetized mechanically ventilated healthy animals to obtain total respiratory system impedance (Zrs) at 0, 3, and 6 cmH2O PEEP levels. Esophageal pressure was measured by a catheter-tip micromanometer to separate Zrs into pulmonary (ZL) and chest wall (Zcw) components. A model containing a frequency-independent Newtonian resistance (RN), inertance, and a constant-phase tissue damping (G) and elastance (H) was fitted to Zrs, ZL, and Zcw spectra. The contribution of Zcw to RN was negligible in all species and PEEP levels studied. However, the participation of Zcw in G and H was significant in all species and increased significantly with increasing PEEP and animal size (rabbit > rat > mice). Even in mice, the chest wall contribution to G and H was still considerable, reaching 47.0 ± 4.0(SE)% and 32.9 ± 5.9% for G and H, respectively. These findings demonstrate that airway parameters can be assessed from respiratory system mechanical measurements. However, the contribution from the chest wall should be considered when intact-chest measurements are used to estimate lung parenchymal mechanics in small laboratory models (even in mice), particularly at elevated PEEP levels. NEW & NOTEWORTHY In species commonly used in respiratory research (rabbits, rats, mice), esophageal pressure-based estimates revealed negligible contribution from the chest wall to the Newtonian resistance. Conversely, chest wall participation in the viscoelastic tissue mechanical parameters increased with body size (rabbit > rat > mice) and positive end-expiratory pressure, with contribution varying between 30 and 50%, even in mice. These findings demonstrate the potential biasing effects of the chest wall when lung tissue mechanics are inferred from intact-chest measurements in small laboratory animals.

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Section: Introductionmentioning

confidence: 94%

Different contributions from lungs and chest wall to respiratory mechanics in mice, rats, and rabbits

Südy

Fodor

Rocha

et al. 2019

Journal of Applied Physiology

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“…A few years later, Grodins et al (1954) created the first dynamic model of the respiratory system. With improving computing power, more sophisticated dynamic models emerged in the 1960s (Bates, 2015; Mitzner, 2011). The early development of excellent models of lung mechanics was possible because of a solid understanding of the physics, mechanics, anatomy, and function of the respiratory system.…”

Section: Anchor Models Of Cfmentioning

confidence: 99%

Mathematical models of cystic fibrosis as a systemic disease

Olivença

Davis

Kumbale

et al. 2023

WIREs Mechanisms of Disease

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Cystic fibrosis (CF) is widely known as a disease of the lung, even though it is in truth a systemic disease, whose symptoms typically manifest in gastrointestinal dysfunction first. CF ultimately impairs not only the pancreas and intestine but also the lungs, gonads, liver, kidneys, bones, and the cardiovascular system. It is caused by one of several mutations in the gene of the epithelial ion channel protein CFTR. Intense research and improved antimicrobial treatments during the past eight decades have steadily increased the predicted life expectancy of a person with CF (pwCF) from a few weeks to over 50 years. Moreover, several drugs ameliorating the sequelae of the disease have become available in recent years, and notable treatments of the root cause of the disease have recently generated substantial improvements in health for some but not all pwCF. Yet, numerous fundamental questions remain unanswered. Complicating CF, for instance in the lung, is the fact that the associated insufficient chloride secretion typically perturbs the electrochemical balance across epithelia and, in the airways, leads to the accumulation of thick, viscous mucus and mucus plaques that cannot be cleared effectively and provide a rich breeding ground for a spectrum of bacterial and fungal communities. The subsequent infections often become chronic and respond poorly to antibiotic treatments, with outcomes sometimes only weakly correlated with the drug susceptibility of the target pathogen. Furthermore, in contrast to rapidly resolved acute infections with a single target pathogen, chronic infections commonly involve multi‐species bacterial communities, called “infection microbiomes,” that develop their own ecological and evolutionary dynamics. It is presently impossible to devise mathematical models of CF in its entirety, but it is feasible to design models for many of the distinct drivers of the disease. Building upon these growing yet isolated modeling efforts, we discuss in the following the feasibility of a multi‐scale modeling framework, known as template‐and‐anchor modeling, that allows the gradual integration of refined sub‐models with different granularity. The article first reviews the most important biomedical aspects of CF and subsequently describes mathematical modeling approaches that already exist or have the potential to deepen our understanding of the multitude aspects of the disease and their interrelationships. The conceptual ideas behind the approaches proposed here do not only pertain to CF but are translatable to other systemic diseases.This article is categorized under: Congenital Diseases > Computational Models

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“…This disease affects lung tissue and causes the lung to lose its elasticity. This is due to the destruction of elastic tissue [ 2 ]. Despite being affected by disease, the mechanical properties of the lung can act as precise indicators of where and how a disease affects the lung.…”

Section: Introductionmentioning

confidence: 99%

“…Despite being affected by disease, the mechanical properties of the lung can act as precise indicators of where and how a disease affects the lung. Through proper evaluation of lung function and gathering data of variables, such as lung tissue resistance, one can analyse disease progression and potentially develop methods or equipment to assist in treating these pathogens [ 2 ].…”

Section: Introductionmentioning

confidence: 99%

Lung Mechanics: A Review of Solid Mechanical Elasticity in Lung Parenchyma

Bhana

2023

J Elast

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The lung is the main organ of the respiratory system. Its purpose is to facilitate gas exchange (breathing). Mechanically, breathing may be described as the cyclic application of stresses acting upon the lung surface. These forces are offset by prominent stress-bearing components of lung tissue. These components result from the mechanical elastic properties of lung parenchyma. Various studies have been dedicated to understanding the macroscopic behaviour of parenchyma. This has been achieved through pressure-volume analysis, numerical methods, the development of constitutive equations or strain-energy functions, finite element methods, image processing and elastography. Constitutive equations can describe the elastic behaviour exhibited by lung parenchyma through the relationship between the macroscopic stress and strain. The research conducted within lung mechanics around the elastic and resistive properties of the lung has allowed scientists to develop new methods and equipment for evaluating and treating pulmonary pathogens. This paper establishes a review of mathematical studies conducted within lung mechanics, centering on the development and implementation of solid mechanics to the understanding of the mechanical properties of the lung. Under the classical theory of elasticity, the lung is said to behave as an isotropic elastic continuum undergoing small deformations. However, the lung has also been known to display heterogeneous anisotropic behaviour associated with large deformations. Therefore, focus is placed on the assumptions and development of the various models, their mechanical influence on lung physiology, and the development of constitutive equations through the classical and non-classical theory of elasticity. Lastly, we also look at lung blast mechanics. No explicit emphasis is placed on lung pathology.

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Mechanical Properties of the Lung

Cited by 9 publications

References 92 publications

Different contributions from lungs and chest wall to respiratory mechanics in mice, rats, and rabbits

Different contributions from lungs and chest wall to respiratory mechanics in mice, rats, and rabbits

Mathematical models of cystic fibrosis as a systemic disease

Lung Mechanics: A Review of Solid Mechanical Elasticity in Lung Parenchyma

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