Document Detail

Ultrasound-induced lung hemorrhage: role of acoustic boundary conditions at the pleural surface.
MedLine Citation:
PMID:  11863166     Owner:  NLM     Status:  MEDLINE    
In a previous study [J. Acoust. Soc. Am. 108, 1290 (2000)] the acoustic impedance difference between intercostal tissue and lung was evaluated as a possible explanation for the enhanced lung damage with increased hydrostatic pressure, but the hydrostatic-pressure-dependent impedance difference alone could not explain the enhanced occurrence of hemorrhage. In that study, it was hypothesized that the animal's breathing pattern might be altered as a function of hydrostatic pressure, which in turn might affect the volume of air inspired and expired. The acoustic impedance difference between intercostal tissue and lung would be affected with altered lung inflation, thus altering the acoustic boundary conditions. In this study, 12 rats were exposed to 3 volumes of lung inflation (inflated: approximately tidal volume; half-deflated: half-tidal volume; deflated: lung volume at functional residual capacity), 6 rats at 8.6-MPa in situ peak rarefactional pressure (MI of 3.1) and 6 rats at 16-MPa in situ peak rarefactional pressure (MI of 5.8). Respiration was chemically inhibited and a ventilator was used to control lung volume and respiratory frequency. Superthreshold ultrasound exposures of the lungs were used (3.1-MHz, 1000-Hz PRF, 1.3-micros pulse duration, 10-s exposure duration) to produce lesions. Deflated lungs were more easily damaged than half-deflated lungs, and half-deflated lungs were more easily damaged than inflated lungs. In fact, there were no lesions observed in inflated lungs in any of the rats. The acoustic impedance difference between intercostal tissue and lung is much less for the deflated lung condition, suggesting that the extent of lung damage is related to the amount of acoustic energy that is propagated across the pleural surface boundary.
William D O'Brien; Jeffrey M Kramer; Tony G Waldrop; Leon A Frizzell; Rita J Miller; James P Blue; James F Zachary
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The Journal of the Acoustical Society of America     Volume:  111     ISSN:  0001-4966     ISO Abbreviation:  J. Acoust. Soc. Am.     Publication Date:  2002 Feb 
Date Detail:
Created Date:  2002-02-26     Completed Date:  2002-03-29     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  7503051     Medline TA:  J Acoust Soc Am     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1102-9     Citation Subset:  IM    
Department of Electrical and Computer Engineering, University of Illinois, Urbana 61801, USA.
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MeSH Terms
Hemorrhage / etiology*,  physiopathology*
Lung Diseases / etiology*,  physiopathology*
Models, Biological
Pleura / physiology*
Ultrasonics / adverse effects*
Grant Support

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