Document Detail


Compliance is nonlinear over tidal volume irrespective of positive end-expiratory pressure level in surfactant-depleted piglets.
MedLine Citation:
PMID:  11112126     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Between the lower and the upper inflection point of a quasistatic pressure-volume (PV) curve, a segment usually appears in which the PV relationship is steep and linear (i.e., compliance is high, with maximal volume change per pressure change, and is constant). Traditionally it is assumed that when positive end-expiratory pressure (PEEP) and tidal volume (V T) are titrated such that the end-inspiratory volume is positioned at this linear segment of the PV curve, compliance is constant over VT during ongoing ventilation. The validity of this assumption was addressed in this study. In 14 surfactant-deficient piglets, PEEP was increased from 3 cm H(2)O to 24 cm H(2)O, and the compliance associated with 10 consecutive volume increments up to full VT was determined with a modified multiple-occlusion method at the different PEEP levels. With PEEP at approximately the lower inflection point, compliance was minimal in most lungs and decreased markedly over VT, indicating overdistension. Compliance both increased and decreased within the same breath at intermediate PEEP levels. It is concluded that a PEEP that results in constant compliance over the full VT range is difficult to find, and cannot be derived from conventional respiratory-mechanical analyses; nor does this PEEP level coincide with maximal gas exchange.
Authors:
M Lichtwarck-Aschoff; G Mols; A J Hedlund; V Kessler; A M Markström; J Guttmann; G Hedenstierna; U H Sjöstrand
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  American journal of respiratory and critical care medicine     Volume:  162     ISSN:  1073-449X     ISO Abbreviation:  Am. J. Respir. Crit. Care Med.     Publication Date:  2000 Dec 
Date Detail:
Created Date:  2001-01-24     Completed Date:  2001-01-26     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:  2125-33     Citation Subset:  AIM; IM    
Affiliation:
Department of Surgical Sciences, University Hospital, Uppsala, Sweden. m.lichtwarck-aschoff@t-online.de
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MeSH Terms
Descriptor/Qualifier:
Animals
Bronchoalveolar Lavage / statistics & numerical data
Female
Lung Compliance / physiology*
Male
Positive-Pressure Respiration* / statistics & numerical data
Pulmonary Gas Exchange / physiology
Pulmonary Surfactants / deficiency*
Random Allocation
Swine
Tidal Volume / physiology*
Time Factors
Chemical
Reg. No./Substance:
0/Pulmonary Surfactants
Comments/Corrections
Comment In:
Am J Respir Crit Care Med. 2001 Jan;163(1):2-3   [PMID:  11208613 ]

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


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