Document Detail


CO2 elimination at varying inspiratory pause in acute lung injury.
MedLine Citation:
PMID:  17204030     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Previous studies have indicated that, during mechanical ventilation, an inspiratory pause enhances gas exchange. This has been attributed to prolonged time during which fresh gas of the tidal volume is present in the respiratory zone and is available for distribution in the lung periphery. The mean distribution time of inspired gas (MDT) is the mean time during which fractions of fresh gas are present in the respiratory zone. All ventilators allow setting of pause time, T(P), which is a determinant of MDT. The objective of the present study was to test in patients the hypothesis that the volume of CO(2) eliminated per breath, V(T)CO(2), is correlated to the logarithm of MDT as previously found in animal models. Eleven patients with acute lung injury were studied. When T(P) increased from 0% to 30%, MDT increased fourfold. A change of T(P) from 10% to 0% reduced V(T)CO(2) by 14%, while a change to 30% increased V(T)CO(2) by 19%. The relationship between V(T)CO(2) and MDT was in accordance with the logarithmic hypothesis. The change in V(T)CO(2) reflected to equal extent changes in airway dead space and alveolar PCO(2) read from the alveolar plateau of the single breath test for CO(2). By varying T(P), effects are observed on V(T)CO(2), airway dead space and alveolar PCO(2). These effects depend on perfusion, gas distribution and diffusion in the lung periphery, which need to be further elucidated.
Authors:
J Aboab; L Niklason; L Uttman; A Kouatchet; L Brochard; B Jonson
Publication Detail:
Type:  Clinical Trial; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Clinical physiology and functional imaging     Volume:  27     ISSN:  1475-0961     ISO Abbreviation:  Clin Physiol Funct Imaging     Publication Date:  2007 Jan 
Date Detail:
Created Date:  2007-01-05     Completed Date:  2007-03-15     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  101137604     Medline TA:  Clin Physiol Funct Imaging     Country:  England    
Other Details:
Languages:  eng     Pagination:  2-6     Citation Subset:  IM    
Affiliation:
Medical Intensive Care Unit, INSERM U492, Hôpital H. Mondor, Créteil, France.
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MeSH Terms
Descriptor/Qualifier:
Aged
Carbon Dioxide / metabolism*
Female
Humans
Inhalation*
Male
Middle Aged
Pulmonary Gas Exchange*
Respiration, Artificial*
Respiratory Dead Space*
Respiratory Distress Syndrome, Adult / physiopathology*,  therapy*
Respiratory Mechanics*
Chemical
Reg. No./Substance:
124-38-9/Carbon Dioxide

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


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