Document Detail

Impact of analysis interval on the multiple exhalation flow technique to partition exhaled nitric oxide.
MedLine Citation:
PMID:  20082344     Owner:  NLM     Status:  MEDLINE    
Exhaled nitric oxide (eNO) is elevated in asthmatics and is a purported marker of airway inflammation. By measuring eNO at multiple flows and applying models of eNO exchange dynamics, the signal can be partitioned into its proximal airway [J' aw NO (nl/sec)] and distal airway/alveolar contributions [CA(NO)(ppb)]. Several studies have demonstrated the potential significance of such an approach in children with asthma. However, techniques to partition eNO are variable, limiting comparisons among studies. The objective of this study is to examine the impact of the analysis interval (time or volume) on eNO plateau concentrations and the estimation of J' aw NO and CA(NO). In 30 children with mild to moderate asthma, spirometry and eNO at multiple flows (50, 100, and 200 ml/sec) were measured. The plateau concentration of eNO at each flow was determined using two different methods of analysis: (1) constant time interval and (2) constant volume interval. For both methods of analysis, a two-compartment model with axial diffusion was used to characterize J' aw NO and CA(NO). At a flow of 200 ml/sec, the time interval analysis predicts values for eNO that are smaller than the volume interval analysis. As a result, there are significant differences in CA(NO) between the methods of analysis (volume > time). When using the multiple flow technique to partition eNO, the method of analysis (constant time vs. constant volume interval) significantly affects the estimation of CA(NO), and thus potentially the assessment and interpretation of distal lung inflammation.
James L Puckett; Richard W E Taylor; Stanley P Galant; Steven C George
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Pediatric pulmonology     Volume:  45     ISSN:  1099-0496     ISO Abbreviation:  Pediatr. Pulmonol.     Publication Date:  2010 Feb 
Date Detail:
Created Date:  2010-01-27     Completed Date:  2010-04-01     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8510590     Medline TA:  Pediatr Pulmonol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  182-91     Citation Subset:  IM    
Copyright Information:
(c) 2010 Wiley-Liss, Inc.
Department of Biomedical Engineering, University of California at Irvine, Irvine, California 92697, USA.
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MeSH Terms
Asthma / physiopathology*
Biological Markers
Breath Tests
Inflammation / physiopathology*
Nitric Oxide / chemistry*
Grant Support
Reg. No./Substance:
0/Biological Markers; 10102-43-9/Nitric Oxide

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