Abstract:

Heil, M. (1999) Airway Closure: Occluding Liquid Bridges in Strongly Buckled Elastic Tubes. ASME Journal of Biomechanical Engineering 121, 487-493.

This paper is concerned with the airway closure problem and investigates the deformation characteristics of strongly collapsed (buckled) airways which are occluded by liquid bridges of high surface tension. The airway wall is modelled as a thin-walled elastic shell which deforms in response to an external pressure and to the compression due to the surface tension of the liquid bridge. The governing equations are solved numerically. It is shown that for physiologically realistic parameter values, axisymmetric and partially collapsed (i.e. buckled but without opposite wall contact) configurations are statically unstable. The deformation characteristics of strongly collapsed airways whose walls are in opposite wall contact show a pronounced hysteresis during the collapse/reopening cycle. Buckling is shown to occur over a short axial length with moderate circumferential wavenumbers. Finally, further implications of the results for the airway collapse/reopening problem are discussed.