Human ciliary beat frequency in epithelium from intrathoracic and extrathoracic airways

Respiratory tract ciliary beat frequency (CBF) was studied to investigate the relation between nasal and tracheal CBF and the possible existence of a gradient of ciliary activity in the human tracheobronchial tree. Ciliary beat frequency was measured photometrically in nasal, tracheal, and lower lobe bronchial brushings obtained at bronchoscopy in 25 patients and in nasal, tracheal, and subsegmental airway brushings in a further 12 patients. Mean (+/- 1 SD) beat frequencies for nasal, tracheal, lower lobe bronchial, and subsegmental samples were 14.0 +/- 1.5, 14.2 +/- 1.3, 14.3 +/- 1.5, and 10.3 +/- 1.0 beats/s, respectively. Nasal, tracheal, and lower lobe bronchial beat frequencies were not significantly different (p greater than 0.05), but subsegmental airway CBF was slower than each of the others (p less than 0.001); there was a positive correlation between nasal and tracheal CBF (r = 0.71). We conclude that CBF is slower in human peripheral airways, but that nasal and tracheal rates are similar.