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CONVECTIVE FLOW DOMINATES AEROSOL DELIVERY TO THE LUNG SEGMENTS.
MedLine Citation:
PMID:  21474695     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
Most of previous computational studies on aerosol transport in models of the central airways of the human lung have focused on deposition rather than on the transport of particles through these airways to the subtended lung regions. Using a model of the bronchial tree extending from the trachea to the segmental bronchi (J Appl Physiol, 98: 970-980, 2005), we predicted aerosol delivery to the lung segments. The transport of 0.5 to 10 μm-diameter particles was computed at various gravity (G) levels (zero to 1.6G) during steady inspiration (100 to 500 ml/s). For each condition, the normalized aerosol distribution among the lung segments was compared to the normalized flow distribution by calculating the ratio (R(i)) between the number of particles exiting each segmental bronchus i, and the flow. When R(i)=1, particle transport was directly proportional to segmental flow. Flow and particle characteristics were represented by the Stokes number (Stk) in the trachea. For Stk<0.01, ratios R(i) were close to one and were unaffected by gravity. For Stk>0.01, R(i) varied greatly among the different outlets (R(i)= 0.30-1.93 in normal gravity for 10 μm at 500 ml/s) and was affected both by gravity and inertia. These data suggest that, for Stk<0.01, ventilation defines the delivery of aerosol to lung segments and that the use of aerosol tracers is a valid technique to visualize ventilation in different parts of the lung. At higher Stokes numbers, inertia, but not gravitational sedimentation is the second major factor affecting the transport of large particles in the lung.
Authors:
Chantal Darquenne; Caroline van Ertbruggen; Gordon Kim Prisk
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2011-4-7
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  -     ISSN:  1522-1601     ISO Abbreviation:  -     Publication Date:  2011 Apr 
Date Detail:
Created Date:  2011-4-8     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Affiliation:
1UCSD.
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