Tidal off-line exhaled nitric oxide measurements in a pre-school population.
Exhaled nitric oxide (ENO) is used as a non-invasive marker of airway inflammation. The aim of this study was to measure ENO in a pre-school population using a relatively novel method, the off-line tidal breathing method, and to investigate differences in ENO between subjects with different presentations of wheezing. ENO was measured in 129 children (median age 4.4 years, quartiles 4.0-4.8 years) through a mouth mask attached to a two-way valve with an expiratory resistance of 5 cm H(2)0. Mean tidal ENO concentration (tENO) was calculated from triplicate measurements. Mean +/- SEM tENO for 89 control subjects was 13+/-0.4 ppb (95%CI 11.8-13.7 ppb); this level was significantly different from tENO in 15 children with a history of recurrent wheezing (18.6+/-1.9 ppb; 95%CI 14.5-22.7 ppb; t-test P<0.0001). Mean tENO in 16 children with a single wheezing episode was 11.4+/-1.0 ppb (95%CI 9.2-13.6 ppb) and thus significantly different from the recurrent wheezing group (t-test P=0.0024).


CONCLUSIONS
The off-line tidal breathing method is a feasible and appealing method for measuring exhaled nitric oxide in pre-school children. With this method, higher tidal exhaled nitric oxide levels were found in children with recurrent wheezing.
Paediatric Pulmonology Department, University Hospital Gasthuisberg, Herestraat 49, 3000, Leuven, Belgium.
Isabelle
I
Meyts
Paediatric Pulmonology Department, University Hospital Gasthuisberg, Herestraat 49, 3000, Leuven, Belgium.
Marijke
M
Proesmans
Youth Health Care Centre, Centre for Preventive Medicine, Leuven, Belgium.
Veerle Van
VV
Gerven
Youth Health Care Centre, Centre for Preventive Medicine, Leuven, Belgium.
Karel
K
Hoppenbrouwers
Paediatric Pulmonology Department, University Hospital Gasthuisberg, Herestraat 49, 3000, Leuven, Belgium. Christiane.DeBoeck@uz.kuleuven.ac.be.
Kris
K
De Boeck
D001944:Breath Tests; D002675:Child, Preschool; D006801:Humans; D009569:Nitric Oxide / Q000032:analysis*; D012008:Recurrence; D012135:Respiratory Sounds / Q000503:physiopathology*
D009569:Nitric Oxide