Physiological and hypertonic saline solutions impair ciliary activity in vitro

Objective. Physiological saline (NaCl 0.9%) is commonly used in treating acute and chronic rhinosinusitis and as a control medium, vehicle, or solvent in studies on ciliary beat frequency (CBF). Hypertonic saline (NaCl 7% and 14.4%) has been applied to enhance mucociliary transport in patients with cystic fibrosis or asthma. Therefore we tried to document the in-vitro effects of these saline solutions on CBF. Materials and methods. The effects on CBF of cryopreserved mucosa of the sphenoidal sinus was measured by a photoelectrical method. Initial frequencies, measured in Locke-Ringer's solution (LR), were compared to CBF after exposure to NaCl in concentrations of 0.9, 7.0 and 14.4%. Results. NaCl 0.9% has a moderately negative effect on CBF. The 7% solution leads to a complete ciliostasis within 5 min. This effect is reversible after rinsing with LR. The 14.4% solution has an irreversible ciliostatic effect. Conclusion. LR is an isotonic solution that has no effect on CBF. Therefore it is probable that this solution is more appropriate than saline for nasal irrigation and nebulization or antral lavage. Moreover, this study suggests that mucolytic effects induced by hyperosmolarity should preferably be attained with hypertonic saline 7% in patients with cystic fibrosis or asthma.