Heliox: an advanced method for targeted drug delivery in respiratory airways

Background: Advancing treatment response in pulmonary diseases and health risk assessments requires a comprehensive understanding of the flow dynamics within the human respiratory tract. While current literature underscores high particle deposition in the Extrathoracic region during air inhalation, the significant impact of different inhalation gases such as heliox on particle transportation and deposition in the human lung airways remains an unexplored frontier. Methods: In the current study, a computational fluid dynamics-based discrete phase model is employed to analyze the flow of particles and two inhalation gases: air and heliox in a realistic tracheobronchial lung model. A realistic anatomical model of tracheobronchial airways, extending from the trachea to the fifth generation, is employed. Significant Findings: Lower pressure distribution and turbulent kinetic energy in the upper lung generations are reported during heliox inhalation. In case of breathing atmospheric air, comparatively higher deposition efficiencies of particles in the trachea and airway generations at multiple inlet flow rates have been found. In particular, the deposition percentages of inhaled particles from the trachea to generation 5 are 44.4 % for air inhalation and 37.12 % for heliox inhalation under resting condition. Knowledge of particle deposition hotspots in the tracheobronchial lung for air and heliox will lead to improved targeted drug delivery.