Abstract
Exchange of air between the nasal cavity and paranasal sinuses has not been fully understood. We established a model of the nasal cavity and paranasal sinuses to investigate ventilation between the two nasal compartments by measuring changes in topical pressures and concentrations of owing media. Flowing media used in the study were water and air.
As a hydraulic experiment, the entire model was filled with water and a pulsation ow was generated by a piston. Topical pressures were measured, then the cavity and the sinus of the model were filled with water solutions of different concentrations, and the flow was generated. The change in concentrations of the solution in the sinus were measured with an absorptiometer using a He-Ne laser. Exchange rates of the medium in the sinus per one respiration were calculated. In both series, the rotating speed of the piston and the capacity of the sinus were varied.
As an aerodinamic experiment, resistance was applied to the glass model and a pulsation flow was generated by a pump with a 450 ml displacement. Pressures in the cavity and sinus were measured. The resistance and the diameter of the sinus ostium were varied.
The hydraulic experiment showed that there was a phase difference between the changes in pressures in the cavity and that in the sinus. It was also found that the changes in pressures in the sinus increased with rotating speed of the piston, which presumably resulted to increased ventilation between the two compartments. When the capacity of the sinus was small, the exchange rate was more than double. The capacity of the sinus was not related to the changes in pressures but it was closely related to diffusion of the medium.
The aerodinamic experiment showed that the pressure both in the cavity and the sinus increased with the resistance. The pressures in the cavity and that in the sinus changed almost identically even when the diameter of the sinus ostium was small. It was speculated that the presence of resistance in the posterior cavity increased in the air ow into the sinus.
