Document Detail


Noninvasive assessment of normality of V (D)/V (T) in clinical cardiopulmonary exercise testing utilizing incremental cycle ergometry.
MedLine Citation:
PMID:  22562602     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
Dead space to tidal volume ratio (V (D)/V (T)), a measure of pulmonary gas exchange efficiency, cannot be accurately calculated without arterial blood sampling. We sought to determine, in patients presenting for diagnostic cardiopulmonary exercise tests, whether there are ranges of the ratio of exhaled ventilation to carbon dioxide output (V (E)/VCO(2)) measured at the lactate threshold that are highly predictive of normality or abnormality of exercise V (D)/V (T) (below or above 0.3) and whether other demographic or physiologic variables aid in this prediction. We reviewed 691 incremental cycle ergometer cardiopulmonary exercise tests featuring breath-by-breath gas exchange measurement and serial arterial blood sampling that were performed for patients with a range of disorders. When V (E)/VCO(2) at the lactate threshold was ≤28, 96 % of subjects had normal V (D)/V (T). For V (E)/VCO(2) 29-32, V (D)/V (T) was normal in 83 % of cases. V (E)/VCO(2) of 33-38 provided no useful information; V (D)/V (T) was normal and abnormal in 50 % of cases each. When V (E)/VCO(2) was ≥39, V (D)/V (T) was abnormal in 87 % of cases. For V (E)/VCO(2) ≥ 39, when FEV(1)/VC was <70 %, V (D)/V (T) was abnormal in 95 % of cases. End-tidal PCO(2) was of no help in distinguishing V (D)/V (T) normality in any V (E)/VCO(2) range. Our results reveal that certain values of V (E)/VCO(2) at LT (V (E)/VCO(2) ≤ 28 and V (E)/VCO(2) ≥ 39), but not others (V (E)/VCO(2) 29-32 and especially V (E)/VCO(2) of 33-38), can be helpful in determining normality of V (D)/V (T) during exercise in patients presenting for cardiopulmonary exercise testing.
Authors:
Michael A Roman; James D Casaburi; Janos Porszasz; Richard Casaburi
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-5-6
Journal Detail:
Title:  European journal of applied physiology     Volume:  -     ISSN:  1439-6327     ISO Abbreviation:  -     Publication Date:  2012 May 
Date Detail:
Created Date:  2012-5-7     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100954790     Medline TA:  Eur J Appl Physiol     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Affiliation:
Division of Pulmonary Medicine, University of Calgary, Calgary, Canada, mroman@ucalgary.ca.
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