Lung Tissue Mechanics Research Articles

Tissue viscance during induced constriction in rabbit lungs: morphological-physiological correlations

Tissue viscance (Vti), the pressure drop across the lung tissues in phase with flow, increases after induced constriction. To gain information about the possible site of response, we induced increases in Vti with methacholine (MCh) and attempted to correlate these changes with alterations in lung morphology. We measured tracheal (Ptr) and alveolar pressure (PA) in open-chest rabbits during mechanical ventilation [frequency = 1 Hz, tidal volume = 5 ml/kg, positive end-expiratory pressure (PEEP) = 5 cmH2O] under control conditions and after administration of saline or MCh (32 or 128 mg/ml) aerosols. We calculated lung elastance (EL), lung resistance (RL), Vti, and airway resistance (Raw) by fitting the equation of motion to changes in Ptr and PA. The lungs were then frozen in situ with liquid nitrogen (PEEP = 5 cmH2O), excised, and processed using freeze substitution techniques. Airway constriction was assessed by measuring the ratio of the airway lumen (A) to the ideally relaxed area (Ar). Tissue distortion was assessed by measuring the mean linear intercept between alveolar walls (Lm), the standard deviation of Lm (SDLm), and an atelectasis index (ATI) derived by calculating the ratio of tissue to air space using computer image analysis. RL, Vti, and EL were significantly increased after MCh, and Raw was unchanged. A/Ar, Lm, SDLm, and ATI all changed significantly with MCh. Log-normalized change (% of baseline) in Vti significantly correlated with A/Ar (r = -0.693), Lm (r = 0.691), SDLm (r = 0.648), and ATI (r = 0.656). Hence, changes in lung tissue mechanics correlated with changes in morphometric indexes of parenchymal distortion and airway constriction.(ABSTRACT TRUNCATED AT 250 WORDS)

A nonlinear viscoelastic model of lung tissue mechanics

There have been a number of attempts recently to use linear models to describe the low-frequency (0-2 Hz) dependence of lung tissue resistance (Rti) and elastance (Eti). Only a few attempts, however, have been made to account for the volume dependence of these quantities, all of which require the tissues to be plastoelastic. In this paper we specifically avoid invoking plastoelasticity and develop a nonlinear viscoelastic model that is also capable of accounting for the nonlinear and frequency-dependent features of lung tissue mechanics. The model parameters were identified by fitting the model to data obtained in a previous study from dogs during sinusoidal ventilation. The model was then used to simulate pressure and flow data by use of various types of ventilation patterns similar to those that have been employed experimentally. Rti and Eti were estimated from the simulated data by use of four different estimation techniques commonly applied in respiratory mechanics studies. We found that the estimated volume dependence of Rti and Eti is sensitive to both the ventilation pattern and the estimation technique, being in error by as much as 217 and 22%, respectively.

Glottis opening and airway resistance.

Glottis opening and airway resistance.

Stress distribution in lungs: a model of pulmonary elasticity.

MEAD, JERE, TAMOTSU TAKISHIMA, AND DAVID LEITH. Stress distribution in lungs: a model of pulmonary elasticity. J. Appl. Physiol. 28(5) : 596-608. 1970.Although lungs are exposed to transpulmonary pressure, the air spaces within are distended solely by forces applied from surrounding tissues. By relating these forces to the areas on which they operate, we derive the effective pressure distending air spaces. In uniformly expanded lungs this pressure probably approximates transpulmonary pressure. In nonuniformly expanded lungs the effective distending pressure differs from transpulmonary pressure, and in the appropriate sign to reduce the nonuniformity. This interdependence of air-space distention bears on a number of aspects of pulmonary function, including the size of air spaces which may be expanded from the gas-free state, the static and dynamic stability of air spaces, the dryness of air spaces, the forces distending airways and blood vessels within lungs, and the distribution of pulmonary edema. The principal function of the mechanical interdependence would appear to be to support uniform expansion of air spaces. The principal functional risk that it entails is increase in capillary transmural pressure in regions which become subjected to abnormally high outward-acting stress.

Lung tissue resistance and pulmonary hysteresis.

ArticleLung tissue resistance and pulmonary hysteresis.H BachofenH BachofenPublished Online:01 Mar 1968https://doi.org/10.1152/jappl.1968.24.3.296MoreSectionsPDF (1 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformation Cited BySimulation of blast lung injury induced by shock waves of five distances based on finite element modeling of a three-dimensional rat5 March 2019 | Scientific Reports, Vol. 9, No. 1A viscoelastic nonlinear compressible material model of lung parenchyma – Experiments and numerical identificationJournal of the Mechanical Behavior of Biomedical Materials, Vol. 94Pressure-Volume Loop22 February 2018Role of Tissue Viscoelasticity in the Pathogenesis of Ventilator-induced Lung InjuryF ifty Y ears of R esearch in ARDS.Respiratory Mechanics in Acute Respiratory Distress SyndromeAmerican Journal of Respiratory and Critical Care Medicine, Vol. 196, No. 7Dissipated Energy is a Key Mediator of VILI: Rationale for Using Low Driving PressuresLung Mechanics22 April 2016A model of lung parenchyma stress relaxation using fractional viscoelasticityMedical Engineering & Physics, Vol. 37, No. 8Mechanical Properties of the LungOscillation Mechanics of the Respiratory System1 July 2011Respiratory system dynamical mechanical properties: modeling in time and frequency domain19 May 2011 | Biophysical Reviews, Vol. 3, No. 2Cardiopulmonary Effects of Matching Positive End-Expiratory Pressure to Abdominal Pressure in Concomitant Abdominal Hypertension and Acute Lung InjuryJournal of Trauma: Injury, Infection & Critical Care, Vol. 69, No. 2Lung Parenchymal Mechanics in Health and DiseaseDébora S. Faffe and Walter A. Zin1 July 2009 | Physiological Reviews, Vol. 89, No. 3Relations Between Fractional-Order Model Parameters and Lung Pathology in Chronic Obstructive Pulmonary DiseaseIEEE Transactions on Biomedical Engineering, Vol. 56, No. 4Effects of amiodarone on lung tissue mechanics and parenchyma remodelingRespiratory Physiology & Neurobiology, Vol. 162, No. 2Respiratory Mechanics and Lung Parenchyma Remodelling in Acute Respiratory Distress SyndromeOn the preparation of lung strip for tissue mechanics measurementRespiratory Physiology & Neurobiology, Vol. 134, No. 3Lung tissue mechanics and extracellular matrix composition in a murine model of silicosisDébora S. Faffe, Gabriela H. Silva, Pedro M. P. Kurtz, Elnara M. Negri, Vera L. Capelozzi, Patricia R. M. Rocco, and Walter A. Zin1 April 2001 | Journal of Applied Physiology, Vol. 90, No. 4Hysteresis of the nasal pressure-flow relationship during hyperpnea in normal subjectsYong-Xin Shi, Margaret Seto-Poon, and John R. Wheatley1 July 1998 | Journal of Applied Physiology, Vol. 85, No. 1Airway mechanics, gas exchange, and blood flow in a nonlinear model of the normal human lungC. H. Liu, S. C. Niranjan, J. W. Clark, K. Y. San, J. B. Zwischenberger, A. Bidani, and (With the Technical Assistance of H. B. Winnike, C. Vanouye, and J. B. Olansen)1 April 1998 | Journal of Applied Physiology, Vol. 84, No. 4Partitioning of alterations in pulmonary mechanics due to vascular engorgement in pigletsPediatric Pulmonology, Vol. 25, No. 1Volume Dependence of Respiratory Impedance in InfantsAmerican Journal of Respiratory and Critical Care Medicine, Vol. 156, No. 4Partitioning airway and lung tissue resistances in humans: effects of bronchoconstrictionDavid W. Kaczka, Edward P. Ingenito, Bela Suki, and Kenneth R. Lutchen1 May 1997 | Journal of Applied Physiology, Vol. 82, No. 5Greater airway narrowing in immature than in mature rabbits during methacholine challengeX. Shen, V. Bhargava, G. R. Wodicka, C. M. Doerschuk, S. J. Gunst, and R. S. Tepper1 December 1996 | Journal of Applied Physiology, Vol. 81, No. 6Regional ventilation in statically and dynamically hyperinflated dogsRolf D. Hubmayr, and Susan S. Margulies1 October 1996 | Journal of Applied Physiology, Vol. 81, No. 4Surface properties of rat pulmonary surfactant studied with the captive bubble method: adsorption, hysteresis, stabilityBiochimica et Biophysica Acta (BBA) - Biomembranes, Vol. 1103, No. 1Ventilation: Total, Alveolar, and Dead Space1 January 2011Partitioning of pulmonary resistance in Friesian calvesResearch in Veterinary Science, Vol. 42, No. 3Tests of Mechanical Function1 January 2011AtemphysiologieDigital computer simulation of respiratory mechanicsComputers and Biomedical Research, Vol. 6, No. 1Comparative studies in lung mechanics based on a survey of literature dataRespiration Physiology, Vol. 8, No. 1 More from this issue > Volume 24Issue 3March 1968Pages 296-301 https://doi.org/10.1152/jappl.1968.24.3.296PubMed5643392History Published online 1 March 1968 Published in print 1 March 1968 Metrics