Document Detail


Alveolar carbon monoxide: a comparison of methods of measurement and a study of the effect of change in body posture.
MedLine Citation:
PMID:  3338251     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
1. We have compared rebreathing, breath-hold and mean alveolar methods of measuring alveolar carbon monoxide (CO), at levels similar to those found in smokers, as a preliminary to using them as indirect measures of carboxyhaemoglobin levels. In the present study alveolar CO levels were raised by rebreathing a 2% CO mixture. 2. Breath-hold CO was measured after breath-hold times of 0-35 s in 5 s increments. Using generalized linear models, the maximum value for breath-hold CO was estimated to occur at 23 s. Breath-hold CO after a 20 and 25 s breath-hold were similar to and significantly greater than those of less than 20 s or greater than 25 s. 3. As expired CO increased, the difference between breath-hold and mean alveolar CO became proportionally larger. On average, breath-hold CO was 24% larger than mean alveolar CO. 4. Rebreathing, breath-hold and mean alveolar CO were compared at four different inspired oxygen concentrations. Expired CO increased significantly with increasing oxygen for all three methods. At end-tidal oxygen levels of less than 25%, breath-hold and rebreathing CO were similar, however, the overall mean difference between the three methods was significant. 5. While rebreathing CO was unaffected by changes in ventilation/perfusion of the lung, induced by change in body posture, both breath-hold and mean alveolar CO showed a significant fall with change from the supine to erect posture.(ABSTRACT TRUNCATED AT 250 WORDS)
Authors:
A J Kirkham; A R Guyatt; G Cumming
Publication Detail:
Type:  Clinical Trial; Comparative Study; Journal Article; Randomized Controlled Trial    
Journal Detail:
Title:  Clinical science (London, England : 1979)     Volume:  74     ISSN:  0143-5221     ISO Abbreviation:  Clin. Sci.     Publication Date:  1988 Jan 
Date Detail:
Created Date:  1988-03-04     Completed Date:  1988-03-04     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  7905731     Medline TA:  Clin Sci (Lond)     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  23-8     Citation Subset:  IM    
Affiliation:
Cardiothoracic Institute, Midhurst, West Sussex, U.K.
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MeSH Terms
Descriptor/Qualifier:
Adult
Breath Tests / methods*
Carbon Monoxide / analysis*
Carboxyhemoglobin / analysis
Female
Humans
Male
Middle Aged
Posture*
Pulmonary Alveoli / metabolism*
Chemical
Reg. No./Substance:
630-08-0/Carbon Monoxide; 9061-29-4/Carboxyhemoglobin

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


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