A dynamic and direct visualization model for the study of nasal airflow

Objective: To evaluate nasal airflow characteristics during physiologic bre athing in normal and pathologic conditions. Design: The choana of an anatomical human model was connected to a pump tha t simulated physiological pressure changes in the upper airway system. Norm al ambient air was used as medium. The airstream was marked with aerosolize d water particles, and was observed through an exact but translucent replic a of the original nasal. septum. Results: In physiologic conditions the airflow is mixed. Turbulence is clea rly visible even with low flow velocities. There is less turbulence with lo wer flow rates. The nasal airflow follows a triphasic pattern of accelerati on, near-steady state, and deceleration. Turbulence is prominent in the fir st and third phases. The main flow stream passes through the middle meatus at all rates. Hypertrophic mucosal membranes and turbinates increase the pr oportion of air passing the middle meatus. With decongested turbinates, flo w distribution is more even. After turbinectomy there is a significant amou nt of airflow passing along the floor of the nose. The olfactory region is aerated only toward the end of inspiration and during the entire expiration phase. Conclusions: This model allows the investigation of airflow distribution an d turbulence under physiologic conditions and the examination of the influe nce of pathologic conditions on these parameters. Overzealous trimming of t urbinates results in an unphysiologic distribution of airflow.