Clearance in Smaller Airways of Inhaled 6-μm Particles in Subjects with Immotile-Cilia Syndrome

Abstract

In subjects with an inherited lack of mucociliary transport, so called immotile-cilia syndrome (ICS), coughing effectively clears particles deposited in larger airways of the tracheobronchial region. The present study investigated clearance in smaller airways of 111In-labeled 6-microm (aerodynamic diameter) monodisperse Teflon particles in six subjects with ICS. The particles were inhaled at an extremely slow flow, 0.05 L/s. Theoretical calculations and experimental data in healthy subjects using this slow flow support particle deposition mainly in smaller ciliated airways, i.e., in bronchioli (generations 12-16). This contrasts with the more centrally deposited pattern obtained using a normal inhalation flow, 0.5 L/s. Lung retention was measured at 0, 24, 48,72 and 96 h. Clearance was significant every 24 h measured over the first 72 h, whereupon it slowed down. The fractions of retained particles were significantly (p < .01) larger than those found for healthy subjects using the slow inhalation flow and those found for ICS subjects using a normal inhalation flow. The results indicate that clearance of particles in smaller airways is incomplete and that cough cannot fully compensate for the lack of mucociliary transport in this region.

Estimation of Mucus Clearance in Pulmonary Airways by Means of a Regression Model

“…King et al [16] stated that samples with higher elasticity cleared less well. An increased amount of mucus seems to improve clearance stated by Svartengren et al [17]. From our studies, we observed that generally an adhesive surface has higher impact and slippery surface has lower impact whereas a dry surface is in-between.…”

Long-term clearance from small airways in patients with cystic fibrosis

“…However, when particles are deposited in small airways, the retained fraction at 72 and 96 h is significantly larger in these patient groups, compared to that of healthy subjects [12,13].…”

“…Clearance on days 1-7 was larger in the CF patients, 22% (15-29) compared to the healthy subjects, 14% (12)(13)(14)(15)(16). No difference was observed between the CF patients and the healthy subjects in the slow clearance phase at day 7 to day 21, representing small airway clearance.…”

Primary ciliary dyskinesia: a consensus statement on diagnostic and treatment approaches in children

“…However, studies on mucociliary clearance in patients with PCD are sparse [72][73][74][75][76]. Nasal mucociliary clearance can be used as a screening tool for PCD, even in infants.…”