title: Exhaled nitric oxide measurements with dynamic flow restriction in children aged 4-8 yrs.
abstract: Fractional exhaled nitric oxide concentration (FENO) depends on exhalation flow; however, children often are unable to perform controlled flow procedures. Therefore, a device was developed for off-line FENO sampling, with dynamic flow restriction (DFR). The authors compared off-line with on-line FENO, assessed feasibility, and obtained normal values for FENO in children aged 4-8 yrs. Subjects inhaled nitric oxide (NO)-free air and exhaled into the device, where DFR kept exhalation flow constant at 50 mL x s(-1). Dead space air was discarded. Exhaled air was collected in a 150 mL mylar balloon. On-line measurements were performed and values compared with off-line FENO in 19 adult volunteers. Seventy-nine children performed off-line sampling. All samples were analysed with a chemiluminescence NO-analyser. Normal values were obtained in 34 healthy children. There was an excellent correlation between on- and off-line values. Bland and Altman plots showed good agreement between on- and off-line FENO. Seventy-four out of 79 children were able to perform a correct off-line procedure. Geometric mean+/-SEM FENO in healthy children was 4.9+/-1.2 parts per billion (ppb) for male children and 7.6+/-1.1 ppb for female children. It can be concluded that off-line fraction of exhaled nitric oxide measurements with dynamic flow restriction are feasible in young children and correspond to on-line values.
authors.affiliation: Dept of Paediatrics/Respiratory Medicine, Erasmus MC University Medical Center-Sophia Children's Hospital, Rotterdam, The Netherlands.
authors.forename: M W H
authors.initials: MW
authors.lastname: Pijnenburg
authors.forename: E T
authors.initials: ET
authors.lastname: Lissenberg
authors.forename: W
authors.initials: W
authors.lastname: Hofhuis
authors.forename: L
authors.initials: L
authors.lastname: Ghiro
authors.forename: W C J
authors.initials: WC
authors.lastname: Ho
authors.forename: W P
authors.initials: WP
authors.lastname: Holland
authors.forename: J C
authors.initials: JC
authors.lastname: de Jongste
mesh_terms: D000328:Adult; D001249:Asthma / Q000175:diagnosis*; D001944:Breath Tests; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D008163:Luminescent Measurements; D008297:Male; D009569:Nitric Oxide / Q000032:analysis*; D011336:Probability; D011659:Pulmonary Gas Exchange; D012016:Reference Values; D012494:Sampling Studies; D012680:Sensitivity and Specificity; D014797:Vital Capacity
chemical_list: D009569:Nitric Oxide