Inspiratory and expiratory flow from collapsible airbags

Abstract

The pressure-flow relationship in the respiratory system is investigated using a simple experimental model consisting of two collapsible airbags attached to a simulated trachea-bronchus model. The oscillatory pressure and flow during the simulated breathing cycle were determined. It was found that the expiratory flow exhibit characteristics similar to the lung-recoil phenomenon observed clinically. Another interesting feature is that the pressure and flow are almost 180° out of phase. The resistance to flow due to simulated bronchus-obstruction was also determined and related to the clinical measurement of airway resistance based on the body plethysmograph method.