title: Methodological aspects of exhaled nitric oxide measurements in infants.
abstract: Guidelines for the measurement of fractional exhaled nitric oxide (FE(NO)) recommend refraining from lung function tests (LFT) and certain foods and beverages before performing FE(NO) measurements, as they may lead to transiently altered FE(NO) levels. Little is known of such factors in infants. The aim of the present study was to evaluate whether forced expiratory maneuvers, sedation, nasal contamination, and breastfeeding affect FE(NO) values in infants. FE(NO) was measured off-line during tidal breathing by means of a facemask covering nose and mouth. FE(NO) measurements were performed in 45 sedated infants (mean age 12.1 months) who underwent LFT because of airway diseases and in 83 unsedated healthy infants (mean age 4.3 months). In infants with airway diseases, no difference was found in FE(NO) values before and 5 min after LFT (n = 19 infants, p = 0.7) and FE(NO) values before sedation did not differ from FE(NO) values during sedation (n = 10 infants, p = 0.2). Oral FE(NO) values were significantly lower than mixed (nasal + oral) FE(NO) (n = 42 infants, p < 0.001). FE(NO) values before and 5 min after breastfeeding were not different (n = 11 healthy infants, p = 0.57). The short-term reproducibility in healthy infants (n = 54) was satisfactory (intraclass correlation coefficient = 0.94). We conclude that, in infants with airway diseases, LFT prior to FE(NO) measurement did not influence FE(NO) values and FE(NO) values did not change after sedation. Oral FE(NO) values were significantly lower than mixed (oral + nasal) FE(NO), and breastfeeding did not influence FE(NO). Short-term reproducibility in awake healthy infants was good.
authors.affiliation: Department of Pediatric Respiratory Medicine, Erasmus Medical Centre, Sophia Chldren's Hospital, Rotterdam, The Netherlands.
authors.forename: Carmelo
authors.initials: C
authors.lastname: Gabriele
authors.forename: Els C
authors.initials: EC
authors.lastname: van der Wiel
authors.forename: Eveline M
authors.initials: EM
authors.lastname: Nieuwhof
authors.forename: Henriette A
authors.initials: HA
authors.lastname: Moll
authors.forename: Peter J F M
authors.initials: PJ
authors.lastname: Merkus
authors.forename: Johan C
authors.initials: JC
authors.lastname: de Jongste
mesh_terms: D001942:Breast Feeding; D001944:Breath Tests / Q000379:methods; D016022:Case-Control Studies; D016292:Procedural Sedation; D045853:Exhalation; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D007223:Infant; D008297:Male; D009569:Nitric Oxide / Q000032:analysis* / Q000378:metabolism; D012129:Respiratory Function Tests / Q000379:methods*; D012140:Respiratory Tract Diseases / Q000378:metabolism / Q000503:physiopathology
chemical_list: D009569:Nitric Oxide