Nasal mucociliary transport: new evidence for a key role of ciliary beat frequency.

Objectives/hypothesis: Mucociliary transport is an important defense mechanism of the respiratory tract. Nonetheless, the factors determining mucociliary transport are only partially understood. Ciliary beat frequency is assumed to be one of the main parameters, although the experimental evidence remains inconclusive.

Study Design: Comparing influences on mucociliary transport to influences on ciliary beat frequency.

Methods: The present study measures the effects on mucociliary transport of two ciliary beat frequency-inhibiting compounds (0.1% xylometazoline and 0.9% NaCl) and a ciliary beat frequency enhancer (0.1% salbutamol). The measurements were performed by a technetium-99m nebulizing scintigraphic method. The experiments were carried out in 15 healthy young volunteers.

Results: The 0.1% xylometazoline appeared to slow ciliary transport, although the decrease was not significant (P = .44). The 0.9% NaCl did reduce mucociliary transport significantly (P = .033). The 0.1% salbutamol resulted in a highly significant increase of mucociliary transport (P = .009). Xylometazoline brings about drastic changes in the nasal cavity, both anatomically and physiologically. Any comparison of mucociliary transport before and after using this vasoconstrictive agent must take this effect into account.

Conclusions: The present study demonstrates a significant similarity in the effects of NaCl and salbutamol on ciliary beat frequency in vitro and on mucociliary transport in vivo. The evidence from our experiments suggests that ciliary beat frequency is a determining factor in the mucociliary transport rate in the nose.