Computational fluid dynamics study of the effect of posture on airflow characteristics inside the nasal cavity

Background: Postural changes in nasal airway resistances are of clinical importance when assessing patients with nasal obstruction. Computed tomography (CT) that is used in computational fluid dynamics (CFD) studies is obtained in a supine position, and it is therefore important to identify whether different positions such as supine, prone, and standing/sitting have any influence on flow behavior inside the nasal cavity. Objectives: To study the effect of posture on modeling nasal airflow and evaluate its influence in determining wall shear stress and other parameters. Method: A three-dimensional nasal cavity model was constructed based on CT images of a healthy Malaysian adult nose. Navier-Stokes and continuity equations for steady airflow were solved to examine inspiratory nasal flow. Results: Around a 0.3% change in the average static pressure is observed while changing from a sitting to supine position. A significant drop in velocity was seen while shifting from sitting to supine position. Conclusion: The gravity effect resulting from postural change influences flow parameters suggesting that future CFD studies should consider posture when conducting analyses. The implication of this study on posture holds importance in future studies of drug delivery though the nasal cavity.