Computational Modeling of Surfactant-Laden Liquid Plug Propagation in Capillary Tubes

Pulmonary surfactant is of essential importance in reducing the surface tension on the liquid film that coats the inner surface of the airways and thus making the lung more compliant. Surfactant-deficiency may result in respiratory distress syndrome (RDS), which is especially common in prematurely born neonates. Surfactant replacement therapy (SRT) is a standard treatment, in which a liquid plug with exogenous surfactant is instilled in the trachea, which subsequently propagates by inspiration and spreads the exogenous surfactant to the airways. The efficacy of the treatment depends on various parameters such as the size of the liquid plug, inspiration frequency and the physical properties of the exogenous surfactant. Unsteady simulations are performed to study surfactant-laden liquid plug propagation using finite difference/front-tracking method in order to shed light on the surfactant replacement therapy.