Deposition of a Polydisperse Aerosol in the Upper Respiratory Tract

Abstract: Inhaled pharmaceuticals are commonly used in the treatment of respiratory disease. This method of administration has many advantages but also poses a problem with particles being lost before reaching the target site. Particle deposition in airways is mainly an effect of inertial impaction, gravitational settling and diffusion. What mechanism influences a particle the most depends on the particle aerodynamic diameter and its linear velocity through the airways. To understand the influence of these parameters on the particle deposition in upper airways, an experimental method has been developed and tested on three different airway geometries, represented by 3D-printed airway models, at three different volumetric flow rates (15, 30 and 60 l/min). Results showed an increase in deposition for increasing flow rates, which was expected as a consequence of increasing inertial impaction. The estimated deposited fraction correlated well to CFD modelling, but generating low variability data turned out to be challenging. This problem could be addressed by further development of the aerosol generation technique, as this factor turned out to have a large effect on the calculated deposited fraction.