ABSTRACT
Objective To explore the distribution and changes of the upper respiratory tract pressure in the human body under circulatory respiration conditions.Methods An oral-secondary bronchus model was established based on CT images.The pressure distribution at various parts of the model during circulatory respiration and the pressure distribution at the moment of maximum inspiration or expiration were simulated under a respiratory flow of 60 L/min.Results The pressure difference in the upper respiratory tract increased with the respiratory flow.Some positions with special structures,such as pharynx,larynx,trachea,etc.,showed pressure gradient changes,especially between edge of epiglottis to the trachea and upon the bifurcation point of tracheal.Conclusions The air flow motion,including pressure distribution and variation,is related to the anatomy morphological structure of the respiratory tract,and they interactively influence the respiration process.The flow field characteristics of pressure cyclic variation can provide basis for exploring the aerosol deposition and the occurrence and treatment of some respiratory tract diseases.