Journal article
Constant-phase descriptions of canine lung, chest wall, and total respiratory system viscoelasticity: Effects of distending pressure
Respiratory physiology & neurobiology, Vol.183(2), pp.75-84
08/15/2012
DOI: 10.1016/j.resp.2012.06.008
PMCID: PMC3409308
PMID: 22691447
Abstract
► We assessed the adequacy of constant-phase descriptions of respiratory tissue viscoelasticity. ► We measured input impedance of the lungs, chest wall and total respiratory system in dogs. ► Each Z was fitted with a constant-phase model with tissue damping, elastance, and hysteresivity. ► Model fitting errors significantly increase for distending pressures greater than 20cm H2O. ► Constant-phase descriptions of respiratory viscoelasticity may be inappropriate near total lung capacity.
The dynamic mechanical properties of the respiratory system reflect the ensemble behavior of its constituent structural elements. This study assessed the appropriateness of constant-phase descriptions of respiratory tissue viscoelasticity at various distending pressures. We measured the mechanical input impedance (Z) of the lungs, chest wall and total respiratory system in 12 dogs at mean airway pressures from 5 to 30cm H2O. Each Z was fitted with a constant-phase model which provided estimates tissue damping (G), elastance (H), and hysteresivity (η=G/H). Both G and H sharply increased with increasing distending pressure for the lungs and chest wall, while η attained a minimum near 15–20cm H2O. Model fitting errors for the lungs and total respiratory system increased for distending pressures greater than 20cm H2O, indicating that constant-phase descriptions of parenchymal and respiratory system viscoelasticty may be inappropriate at volumes closer to total lung capacity. Such behavior may reflect alterations in load distribution across various parenchymal stress-bearing elements.
Details
- Title: Subtitle
- Constant-phase descriptions of canine lung, chest wall, and total respiratory system viscoelasticity: Effects of distending pressure
- Creators
- David W Kaczka - Harvard Medical School, Boston, MA, United StatesJennifer L Smallwood - Department of Anesthesia and Perioperative Medicine, The University of Western Ontario, London, Ontario, Canada
- Resource Type
- Journal article
- Publication Details
- Respiratory physiology & neurobiology, Vol.183(2), pp.75-84
- DOI
- 10.1016/j.resp.2012.06.008
- PMID
- 22691447
- PMCID
- PMC3409308
- NLM abbreviation
- Respir Physiol Neurobiol
- ISSN
- 1569-9048
- eISSN
- 1878-1519
- Publisher
- Elsevier B.V
- Language
- English
- Date published
- 08/15/2012
- Academic Unit
- Roy J. Carver Department of Biomedical Engineering; Radiology; Anesthesia
- Record Identifier
- 9984006356402771
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