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- ERICSSON, CH, et al.
(författare)
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Repeatability of airway deposition and tracheobronchial clearance rate over three days in chronic bronchitis
- 1995
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Ingår i: The European respiratory journal. - : European Respiratory Society (ERS). - 0903-1936 .- 1399-3003. ; 8:11, s. 1886-1893
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Tidskriftsartikel (refereegranskat)abstract
- Previous investigations on tracheobronchial clearance in chronic bronchitis or chronic obstructive pulmonary disease (COPD) have usually referred to measurements during a short time-period, i.e. a few hours. The purpose of this study, therefore, was to study regional particle deposition and tracheobronchial clearance during 72 h. In 14 patients with chronic bronchitis clearance of 111In-labelled 3.6 micrograms Teflon particles and lung function were measured on two occasions, with an interval of 2 weeks. Lung retention of test particles was measured at 0, 24, 48 and 72 h using a profile scanner. The weight of expectorated sputum samples was measured after the two clearance measurements. The particle retentions at all time-points were reproducible, as seen from the two measurements ( r > 0.90). The fast clearance phase was completed within 72 h. No correlation between sputum volume and clearance was seen. There was a significant negative correlation between airway resistance and the 72 h retention (r= -0.66), and an even better correlation between specific airway resistance and the 72 h retention (r = -0.82), indicating more central deposition in obstructed airways. There was no significant correlation between lung function tests reflecting smaller airways and the 72 h retentions. Deposition data agreed well with theoretical calculations and experimental data in healthy subjects. In spite of earlier findings that mucociliary transport is usually severely impaired in chronic bronchitis and COPD, the present results indicate that overall tracheobronchial mucus clearance in these patients is fairly effective, probably due to a productive cough. Alveolar deposition may be estimated by measurements of the 72 h retention in subjects with chronic obstructive pulmonary disease. The 72 h retention is dependent mainly on the calibre of larger airways. The present method of studying airway clearance during 3 days is highly reproducible.
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- Svartengren, K, et al.
(författare)
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Tracheobronchial deposition and clearance in small airways in asthmatic subjects
- 1996
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Ingår i: The European respiratory journal. - : European Respiratory Society (ERS). - 0903-1936 .- 1399-3003. ; 9:6, s. 1123-1129
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Tidskriftsartikel (refereegranskat)abstract
- 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 microns (aerodynamic diameter) monodisperse Teflon particles labelled with 111In. 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.
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