We sought to determine the incidence rate of carpal tunnel syndrome in the general population. Using three different case definitions, we conducted a prospective study to ascertain by medical record review all cases of incident disease in a defined population during a 2-year period. Newly diagnosed probable or definite carpal tunnel syndrome (N = 309) occurred at a rate of 3.46 cases per 1,000 person-years (95% confidence interval = 3.07-3.84). The incidence rate in our study was 3.5 times higher than the rate 20 years ago in a Minnesota city. The rate difference probably results from a combination of reasons, including a true rise in incidence.

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Asthma tends to impair mucociliary clearance, as assessed from measurements in large airways. However, very little is known about clearance in the smallest airways of the tracheobronchial region.Deposition and clearance was estimated in 11 subjects with stable asymptomatic asthma and 10 healthy subjects after inhalation of 6 µm (aerodynamic diameter) monodisperse Teflon particles labelled with 111 In. The particles were inhaled at an extremely slow flow, 0.05 L·s -1 . Theoretical calculations and experimental data in healthy subjects using this slow flow support an enhanced deposition in the tracheobronchial region, in particular in the small ciliated airways (bronchioles). Lung retention was measured at 0, 24, 48 and 72 h.Clearance was significant every 24 h both for asthmatic and healthy subjects, with similar fractions of retained particles at all time-points. The fractions of tracheobronchially-deposited particles were on average 41 and 47% for asthmatic and healthy subjects, respectively, as compared to a maximal deposition of 30% using a normal inhalation flow (0.5 L·s -1 ). No significant correlation was found between lung retention and lung function, either in asthmatics or in healthy subjects.Our results indicate that particles clear equally well from small ciliated airways in asthmatic and healthy subjects, maybe as a consequence of an optimal asthma therapy. Furthermore, our results show that it is possible to enhance tracheobronchial deposition both in healthy and asthmatic subjects, i.e. practically independent of airway dimensions, by inhaling rather large aerosol particles extremely slowly. This may be a useful therapeutic approach.

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.

D De ep po os si it ti io on n o of f i in nh ha al le ed d p pa ar rt ti ic cl le es s i in n t th he e m mo ou ut th h a an nd d t th hrABSTRACT: We previously studied the deposition of inhaled particles in the mouth and throat of asthmatic patients, and found large, reproducible differences among subjects. In the present study, we examined whether anatomical and/or functional differences in the pharynx and larynx could underlie this interindividual variation. Deposition in the mouth and throat, and in the lung was estimated in 16 asthmatic subjects after inhalation of 3.6 µm (aerodynamic diameter) monodisperse Teflon particles labelled with 111 In. The particles were inhaled at a flow rate of 0.5 l·s -1 with maximally deep breaths. Radioactivity was measured by external scanning over head and neck, lungs and stomach, immediately after the inhalation. Radioactivity in the lungs was also measured 24 h later. A measure of the total amount of particles deposited in the mouth and throat was obtained from the added activities in mouthwash, head and neck, and stomach, immediately after the inhalation of the test particles. Pharynx and larynx function was examined by fibreoptic laryngoscopy performed during a corresponding inhalation procedure.Deposition in the mouth and throat varied widely among the subjects, ranging 9-76% (median 12%). We found two subpopulations, 13 subjects in the range 9-34%, and 3 subjects with >70% deposition. Deviations in pharyngeal configuration during inhalation were significantly related to high mouth and throat deposition, whereas functional differences in the larynx were not.Our study shows that mouth and throat deposition may be extremely high in some asthmatics, and that pharyngeal configuration affects deposition of particles in the mouth and throat.