Airway nitric oxide in infants with acute wheezy bronchitis

Abstract

Concentrations of nitric oxide (NO) in exhaled air are increased in children and adults with asthma, and NO measurements are used as a non-invasive marker to monitor airway inflammation in these patients. To define the role of NO in infants with acute wheezy bronchitis, we measured nasal and end-tidal NO concentrations in 17 infants with acute virus-associated wheezy bronchitis, in 22 term infants without respiratory disease, and in nine premature infants. Nasal NO measurements were performed with an olive placed in the infant's nose; end-tidal NO concentrations were assessed during tidal breathing through a snuggly fitting face mask. Both end-tidal NO concentrations and nasal NO concentrations were reduced in infants with acute wheezy bronchitis. There were no differences in NO concentrations between term infants and premature infants. Measurements by both techniques were highly reproducible, as assessed by repeated measurements three times daily on three consecutive days in eight premature infants. Reduced airway NO concentrations in infants with virus-associated acute wheezy bronchitis are in contrast to findings in adults where both upper and lower airway NO levels are increased in patients with asthma. Whether this reflects a different inflammatory reaction to upper airway infections in acutely wheezy infants or pathophysiologic differences in airway response remains to be determined.

Normative data for lung function and exhaled nitric oxide in unsedated healthy infants

“…For infants slightly older than our study participants, there has not been any difference between strictly oral or nasal eNO [50]. Although mixed eNO has been shown in infants to differentiate health from a variety of airway diseases [27,50,51], this must be considered before using our normative values as reference.…”

The Clinical Utility of Fractional Exhaled Nitric Oxide (FeNO) in Asthma Management

“…Therefore, though FeNO appears to reflect eosinophilic bronchial inflammation early in life, the current evidence is insufficient to state that FeNO performed in children at 0 to 4 years of age predicts a diagnosis of asthma at age 5 and above. However; future studies (one is ongoing 176 ) may demonstrate otherwise. The strength of evidence assessment is summarized in Table 6.…”

“…175 The fourth study is an ongoing prospective cohort that has reported only preliminary findings not relevant to this question; final results will be relevant because the study will attempt to develop a prediction rule based on data from demographics, history, specific IgE, FeNO and peak expiratory flow. 176 Another study was only published as an abstract. In a population-based birth cohort, FeNO was measured in 234 healthy term infants aged 5 weeks during quiet tidal breathing in unsedated sleep.…”

“…FeNO measured after birth was associated with increased risk of subsequent respiratory symptoms and in infants of smoking mothers Ratjen 176 …”

Comparison of online single-breath vs. online multiple-breath exhaled nitric oxide in school-age children

“…Here, measurements based on quiet tidal breathing usually result in higher proportions of children being able to perform the maneuver satisfactorily than spirometry as a forced expiratory maneuver, as illustrated in a review on lung function tests in preschool children with cystic fibrosis (16). Until now, multiple-breath eNO (eNOmb) measurements have mostly been performed in infants and toddlers (17)(18)(19)(20)(21). Despite requiring less cooperation beyond infancy, criteria for standardization of eNOmb measurements are not yet included in the current ERS/ATS guidelines due to methodological issues (9).…”