Document Detail


Partitioning of lung and chest-wall mechanics before and after lung-volume-reduction surgery.
MedLine Citation:
PMID:  9655744     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
In the study reported here, we partitioned the mechanics of the respiratory system into lung and chest-wall components, using the rapid occlusion technique in seven patients with severe emphysema before lung-volume-reduction surgery and 3 mo later. Patients showed improvements in 6-min walk (p < 0.01) and dyspnea (p < 0.05). The resistances of the respiratory system and chest wall were not altered by surgery. Ohmic airway resistance did not change, but the component of lung resistance (DeltaRL) due to viscoelastic behavior (stress relaxation) and time-constant inhomogeneities (pendelluft) decreased in six patients (p < 0.03). Dynamic elastance of the lung (Edyn,L) decreased after surgery (p < 0.02), whereas dynamic elastance of the chest wall did not change. The ratio of dynamic intrinsic positive end-expiratory pressure (PEEPi) to static PEEPi, which also reflects viscoelastic properties and time-constant inhomogeneities, increased after surgery (p < 0.05). The decrease in dyspnea was related to the decrease in Edyn,L (r = 0.81, p = 0.03), and tended to be related to the decrease in DeltaRL (r = 0.71, p = 0. 07). In conclusion, lung-volume-reduction surgery decreased dynamic pressure dissipations caused by stress relaxation and time-constant inhomogeneities within lung tissue, and it had no effect on the static mechanical properties of the chest wall.
Authors:
A Jubran; F Laghi; M Mazur; S Parthasarathy; E R Garrity; P J Fahey; M J Tobin
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  American journal of respiratory and critical care medicine     Volume:  158     ISSN:  1073-449X     ISO Abbreviation:  Am. J. Respir. Crit. Care Med.     Publication Date:  1998 Jul 
Date Detail:
Created Date:  1998-07-30     Completed Date:  1998-07-30     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  9421642     Medline TA:  Am J Respir Crit Care Med     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  306-10     Citation Subset:  AIM; IM    
Affiliation:
Division of Pulmonary and Critical Care Medicine, Edward Hines Jr. Veterans Administration Hospital, Hines, IL 60141, USA.
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MeSH Terms
Descriptor/Qualifier:
Aged
Elasticity
Female
Humans
Male
Middle Aged
Pneumonectomy*
Positive-Pressure Respiration
Postoperative Period
Pulmonary Emphysema / surgery*
Respiratory Function Tests
Respiratory Mechanics*

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


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