Document Detail

Influence of unequal ventilation on the single breath K(CO) in COPD revealed by comparison with the rebreathing K(CO).
MedLine Citation:
PMID:  12385736     Owner:  NLM     Status:  MEDLINE    
In 16 patients with chronic obstructive pulmonary disease (COPD) we investigated the relation between unequal ventilation and diffusion by means of lung volumes and Krogh factors (K(CO)) using the single breath (SB) and the rebreathing (RB) methods. We used both methods because the SB measurement is sensitive to unequal ventilation and diffusion whereas the RB measurement is not. Because K(CO) depends on inspired volume (VI), the SB and RB measurement have to be performed at the same VI. We therefore determined K(CO)SBm by making a SB measurement at VI equal to the mean inspired volume during the RB measurement and then calculated K(CO)RBm by dividing the RB transfer factor for CO by the mean RB lung volume. In 10 patients K(CO)SBm/K(CO)RBm, a parameter determined by the combined effect of unequal ventilation and diffusion, was almost equal to unequal ventilation, the quotient of the SB and mean RB lung volumes (VSBm/VRBm), just as in normal subjects (Jansons et al., Respiration 67 (2000) 383). This finding means that we can correct for the effects of unequal ventilation by dividing K(CO)SBm by VSBm/VRBm. We suggest that the SB measurement of K(CO) at vital capacity can be corrected in a similar way.
H Jansons; J K Fokkens; I Tweel van der; J-W Lammers; H Folgering
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Publication Detail:
Type:  Comparative Study; Journal Article    
Journal Detail:
Title:  Respiratory physiology & neurobiology     Volume:  133     ISSN:  1569-9048     ISO Abbreviation:  Respir Physiol Neurobiol     Publication Date:  2002 Oct 
Date Detail:
Created Date:  2002-10-18     Completed Date:  2002-12-31     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  101140022     Medline TA:  Respir Physiol Neurobiol     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  109-19     Citation Subset:  IM    
Lung Function Department of the Heart Lung Division and Centre of Biostatistics, Utrecht University, Utrecht, The Netherlands.
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MeSH Terms
Age Factors
Carbon Monoxide* / analysis
Inspiratory Capacity / physiology
Middle Aged
Pulmonary Disease, Chronic Obstructive / physiopathology*
Pulmonary Ventilation / physiology*
Regression Analysis
Respiratory Function Tests / methods,  statistics & numerical data
Vital Capacity / physiology
Reg. No./Substance:
630-08-0/Carbon Monoxide

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