RT Journal Article
SR Electronic
T1 Comparison of online single-breath versus multiple-breath exhaled nitric oxide at school entry in a cohort of unselected children
JF European Respiratory Journal
JO Eur Respir J
FD European Respiratory Society
SP p3279
VO 38
IS Suppl 55
A1 Oliver Fuchs
A1 Philipp Latzin
A1 Florian Singer
A1 Elena Proietti
A1 Elisabeth Kieninger
A1 Urs Frey
YR 2011
UL http://erj.ersjournals.com/content/38/Suppl_55/p3279.abstract
AB Despite requiring less cooperation there are no standards for online multiple-breath (mb) measurements of exhaled nitric oxide (eNO) with uncontrolled flow rate and no studies comparing them to more difficult online single-breath (sb) eNO measurements in young children.Online eNOsb and eNOmb were measured by a chemoluminescence analyzer connected to an ultrasonic flowmeter in N=73 children of a birth cohort of unselected children at a mean±SD age of 6.1±0.2 years. During measurements, we aimed for 20 tidal breathing manoeuvres for eNOmb and for 3 eNOsb manoeuvres according to current standards. We compared both techniques by standard comparison methods including regression analysis and Bland-Altman plots.After strict quality control, eNOmb and eNOsb measurements were acceptable in n=56 and n=53 children, respectively. Paired data were available for n=46 children (43.5% males). With r2=0.85, p<0.0001, eNOmb was significantly correlated with eNOsb (mean±SD 8.2±5.8 ppb) after computing NO output or after extrapolation to an expiratory flow rate of 50 mL/s (eNOmb50, mean±SD 9.0±5.8 ppb), also on a log-log scale. The mean difference between eNOmb50 and eNOsb according to standards was -0.9 ppb with upper and lower limits of agreement of 3.9 and -5.7 ppb, respectively.At school entry, online eNOmb with uncontrolled flow rate is highly correlated with the gold standard of eNOsb measurements controlling for expiratory flow. The wide range of limits of agreement hampers eNOmb use in population-based research. Being less dependent on cooperation at this age, it might be a promising additional tool for the clinical setting to discriminate between disease groups.