The effect of tissue elastic properties and surfactant on alveolar stability.

Steen Andreassen, Kristoffer L Steimle, Mads L Mogensen, Jorge Bernardino de la Serna, Stephen Rees, Dan S Karbing

Center for Model-Based Medical Decision Support, Aalborg University, Aalborg, Denmark. sa@hst.aau.dk

Journal of applied physiology (Bethesda, Md. : 1985) 2010 Nov

filter terms:

This paper presents a novel mathematical model of alveoli, which simulates the effects of tissue elasticity and surfactant on the stability of human alveoli. The model incorporates a spherical approximation to the alveolar geometry, the hysteretic behavior of pulmonary surfactant and tissue elasticity. The model shows that the alveolus without surfactant and the elastic properties of the lung tissue are always at an unstable equilibrium, with the capability both to collapse irreversibly and to open with infinite volume when the alveolus has small opening radii. During normal tidal breathing, the alveolus can becomes stable, if surfactant is added. Including the passive effect of tissue elasticity stabilizes the alveolus, further allowing the alveoli to be stable, even for lung volumes below residual volume. The model is the first to describe the combined effects of tissue elasticity and surfactant on alveolar stability. The model may be used as an integrated part of a more comprehensive model of the respiratory system, since it can predict opening pressures of alveoli.

Citation

Steen Andreassen, Kristoffer L Steimle, Mads L Mogensen, Jorge Bernardino de la Serna, Stephen Rees, Dan S Karbing. The effect of tissue elastic properties and surfactant on alveolar stability. Journal of applied physiology (Bethesda, Md. : 1985). 2010 Nov;109(5):1369-77