Document Detail


Convective flow dominates aerosol delivery to the lung segments.
MedLine Citation:
PMID:  21474695     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Most previous computational studies on aerosol transport in models of the central airways of the human lung have focused on deposition, rather than 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. Transport of 0.5- to 10-μm-diameter particles was computed at various gravity levels (0-1.6 G) during steady inspiration (100-500 ml/s). For each condition, the normalized aerosol distribution among the lung segments was compared with the normalized flow distribution by calculating the ratio (R(i)) of the number of particles exiting each segmental bronchus i to 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, R(i) values were close to 1 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 particles at 500 ml/s) and was affected 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:
C Darquenne; C van Ertbruggen; G K Prisk
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.     Date:  2011-04-07
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  111     ISSN:  1522-1601     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  2011 Jul 
Date Detail:
Created Date:  2011-07-12     Completed Date:  2013-07-08     Revised Date:  2013-09-26    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol (1985)     Country:  United States    
Other Details:
Languages:  eng     Pagination:  48-54     Citation Subset:  IM    
Affiliation:
Division of Physiology 0931, Department of Medicine, University of California, San Diego, La Jolla, CA 92093-0931, USA. cdarquenne@ucsd.edu
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MeSH Terms
Descriptor/Qualifier:
Administration, Inhalation
Aerosols
Analysis of Variance
Bronchi / anatomy & histology,  physiology*
Computer Simulation*
Gravitation
Humans
Models, Anatomic*
Particle Size
Pharmaceutical Preparations / administration & dosage*
Pulmonary Ventilation*
Rheology*
Time Factors
Trachea / anatomy & histology,  physiology*
Grant Support
ID/Acronym/Agency:
ES-011177/ES/NIEHS NIH HHS; R01 ES011177/ES/NIEHS NIH HHS
Chemical
Reg. No./Substance:
0/Aerosols; 0/Pharmaceutical Preparations
Comments/Corrections

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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