Age-Specific Study of Airflow Distribution, Aerosol Transport and Deposition in an Unhealthy Human Lung using CFD-DPM Approach

Abstract

The pulmonary route is the pathway to transport aerosolised drug particles into the tracheobronchial airways to treat and prevent respiratory diseases. Lung cancer is a frequently diagnosed respiratory disease caused by particulate matter in the environment, especially among older individuals. It is evident that as age increases, the lung airway diameters reduce, and this geometric alteration due to aging affects the breathing capacity, transportation, and deposition (TD) of inhaled drugs. A precise understanding of the inhaled particles TD through age-specific unhealthy respiratory tracts containing a tumor can potentially optimise lung cancer treatment, especially among aged individuals, which has not been investigated in the existing literature. This study investigates the aging effect on the deposition of inhaled drug particles on the glomus tumor present in the upper airways of the human respiratory tract. The CFD model predicts that particle deposition on the tumor wall is higher in the 70-year-old lung for the particle sizes ranging from 5-10 μm, while the maximum deposition efficiency of 10-20 μm particles is found in the lung of a 50-year-old individual. The results of the numerical study show that particle sizes ranging from 10-14 μm are deposited with higher efficiency on the tumor wall as compared to the smaller size particles (5-9 μm) for 50, 60 and, 70 age. The flow disturbances are found maximum in the airway downstream of the tumor. Furthermore, the effect of different inhalation flow rates on particles (TD) is also investigated. The obtained patterns of airflow distribution and deposition efficiency on the tumor wall and in the upper tracheobronchial airways would be beneficial for developing an efficient and targeted drug delivery system.