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The fraction of NO in exhaled air and estimates of alveolar NO in adolescents with asthma: Methodological aspects
Author(s) -
HeijkenskjöldRentzhog Charlotte,
Alving Kjell,
KalmStephens Pia,
Lundberg Jon O,
Nordvall Lennart,
Malinovschi Andrei
Publication year - 2012
Publication title -
pediatric pulmonology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.866
H-Index - 106
eISSN - 1099-0496
pISSN - 8755-6863
DOI - 10.1002/ppul.22556
Subject(s) - medicine , exhalation , asthma , exhaled nitric oxide , nitrite , exhaled air , gastroenterology , exhaled breath condensate , anesthesia , spirometry , toxicology , ecology , nitrate , biology
Rationale This study investigated the oral contribution to exhaled NO in young people with asthma and its potential effects on estimated alveolar NO (Calv NO ), a proposed marker of inflammation in peripheral airways. Secondary aims were to investigate the effects of various exhalation flow‐rates and the feasibility of different proposed adjustments of (Calv NO ) for trumpet model and axial diffusion (TMAD). Methods Exhaled NO at flow rates of 50–300 ml/sec, and salivary nitrite was measured before and after antibacterial mouthwash in 29 healthy young people (10–20 years) and 29 with asthma (10–19 years). Calv NO was calculated using the slope–intercept model with and without TMAD adjustment. Results Exhaled NO at 50 ml/sec decreased significantly after mouthwash, to a similar degree in asthmatic and healthy subjects (8.8% vs. 9.8%, P = 0.49). The two groups had similar salivary nitrite levels (56.4 vs. 78.4 µM, P = 0.25). Calv NO was not significantly decreased by mouthwash. Calv NO levels were similar when flow‐rates between 50–200 or 100–300 ml/sec were used ( P = 0.34 in asthmatics and P = 0.90 in healthy subjects). A positive association was found between bronchial and alveolar NO in asthmatic subjects and this disappeared after the TMAD‐adjustment. Negative TMAD‐adjusted Calv NO values were found in a minority of the subjects. Conclusions Young people with and without asthma have similar salivary nitrite levels and oral contributions to exhaled NO and therefore no antibacterial mouthwash is necessary in routine use. TMAD corrections of alveolar NO could be successfully applied in young people with asthma and yielded negative results only in a minority of subjects. Pediatr Pulmonol. 2012. 47:941–949. © 2012 Wiley Periodicals, Inc.