High frequency oscillations improve nasal mucociliary transport.

The saccharin clearance time technique was used to determine the effect upon nasal mucociliary transport of sine wave oscillations. Nasal air was oscillated at 8 Hz, 14 Hz, and 20 Hz by a loudspeaker attached to a nasal mask. Mucociliary transport was significantly increased at all frequencies with an overall mean rise of 161%. Because sine waves have zero mean pressure and flow, the improvement is more likely to be caused by changes in mucus viscoelasticity or ciliary function rather than by a direct physical effect on mucus velocity. This simple and comfortable technique may have practical application in patients with overproduction or retention of mucus within the nasal passages or intrathoracic airways.