Investigation of the nasal cycle function through endoscopy, rhinoresistometry and acoustic rhinomety.

The cyclic congestion and decongestion in both nasal cavities systematically accompany the nose respiratory function. The turbulent behavior of the nasal airflow seems to be a prerequisite of the adequate contact of inspired air particles with a nasal mucosa. The aim of the present study was to gain further information regarding the turbulent airflow behavior just during the nasal cycle dynamics. The nasal cycles in 10 healthy human subjects were investigated applying endoscopic imaging, rhinoresistometry, and acoustic rhinometry methods. The nasal function has been estimated at the regular intervals of 20 minutes over a time period of 15 hours. The following parameters were calculated in each case: airflow resistance, hydraulic diameter, friction coefficient , transition from the laminar flow to the turbulent one, and minimal cross-sectional areas. In addition to the previously known cyclic changes of the flow resistance and of the nasal width, periodic alterations in the turbulence function were noted. Under the resting phase, the laminar flow was usually demonstrated. Under the working phase, the turbulences arouse already at low flow velocities. The increases of turbulences that supplemented the working phase were caused by the enlargement of the cross-sectional area in the anterior nasal cavum. The latter followed to the decongestion of the mucosa of the head of the inferior turbinate as well as of the septal tuberculum. Rhinoresistometry and acoustic rhinometry predominantly complement each other. Application of both methods provides therefore valuable information on the functional nasal cycle changes. A combination of these two methods is recommended thus for the proper evaluation of the nasal cavity behavior.