Mechanical implications of viscoelasticity
In 1955, Mount  assessed the dynamic work per breath (Wdyn,L) as given by volume-pressure loops in open-chest rats during sinusoidal variations in lung volume. In order to explain the relatively high values of Wdyn,L at the lower frequencies and the progressive decrease in dynamic pulmonary compliance with increasing frequency, he proposed a two-compartment viscoelastic model of the lung which “confers time dependency of the elastic properties.” In 1967 Sharp et al. , who were unaware of Mount’s work, proposed a similar viscoelastic model for both lung and chest wall. Until the late 1980s these models were largely ignored. Since then, however, the viscoelastic properties of the respiratory system have been recognized to play an important role in respiratory dynamics. In this review we describe the implications of viscoelastic mechanisms in terms of a) frequency dependence of pulmonary and chest wall elastance and resistance, b) work of breathing, c) passive lung deflation, and d) forced vital capacity (FVC).
KeywordsChronic Obstructive Pulmonary Disease Chronic Obstructive Pulmonary Disease Patient Forced Vital Capacity Peak Expiratory Flow Adult Respiratory Distress Syndrome
Unable to display preview. Download preview PDF.
- 5.Bates JHT, Brown K, Kochi T (1987) Identifying a model of respiratory mechanics using the interrupted technique. Proceeding of the 9th American Conference. IEEE Eng Med Biol Soc, pp 1802–1803Google Scholar
- 20.Mcllroy MB, Tierney DF, Nadel JA (1963) A new method of measurement of compliance and resistance of lungs and thorax. J Appl Physiol 18:424–427Google Scholar
- 26.Hutchinson J (1846) On capacity of the lungs, and on the respiratory movements, with the view of establishing a precise and easy method of detecting disease by the spirometer. Lancet i:630–632Google Scholar
- 27.Tiffeneau R, Pinelli AF (1947) Air circulant et air captif dans Texploration de la fonc- tion ventilatrice pulmonaire. Paris Med 133:624–628Google Scholar
- 29.Quanjer PhH (1983) Lung volumes and forced ventilatory flows. Report of Working Party. Standal-dization of lung function tests. European Coal and Steel Community. Eur Respir J 6:5–40Google Scholar
- 39.ATS (1997) Standards for the diagnosis and care of patients with chronic obstructive pulmonary disease (COPD) and asthma. Am Rev Respir Dis 136:225–244Google Scholar
- 40.Alexander R McNeill (1988) Elastic mechanisms in animal movement. Cambridge University Press, CambridgeGoogle Scholar