| Autor: |
Stahlhofen, W., Scheuch, G., Bailey, M. R. |
| Zdroj: |
Annals of Occupational Hygiene; 1994 Inhaled Particles VII, Vol. 38, p189-196, 8p |
| Abstrakt: |
The technique of using an aerosol bolus of defined volume injected at a selected moment during inhalation has been applied to investigate the clearance of radioactively labelled particles from the tracheobronchial (TB) tree. In previous experiments subjects inhaled 1–6 μm aerodynamic diameter (dae) particles at a low flow-rate (250 cm3 s−1) and particles were deposited primarily by sedimentation during a breath-hold at the end of inhalation. The fraction (A) of the lung deposit that was not cleared in the rapid phase of mucociliary clearance was close to 1.0 when the bolus was injected at the start of a breath. When the bolus was injected at the end of a breath A was consistently about 0.5 for 1–3 μm dae particles, but reduced to 0.25 at dae = 6 μm. Three subjects inhaled 3.8 jum dae particles at a high flow-rate (660–750 cm3 s−1) to promote deposition by impaction in the bronchi. The value of A was again about 0.5 and thus the results do not support the hypothesis that the observed particle retention is related to specific sites of deposition within the TB tree. [ABSTRACT FROM PUBLISHER] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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