[Recurrent wheezing in three year-olds: facts and opportunities]

[Consensus conference on acute bronchiolitis (v): prevention of acute bronchiolitis. Review of scientific evidence]

A review of the evidence on prevention of acute bronchiolitis is presented. Acute bronchiolitis prevention arises from three basic approaches: preventive treatment to reduce recurrent wheezing following an episode of acute bronchiolitis, preventive treatment to reduce the frequency and severity of RSV bronchiolitis in the population at risk (prematurity, bronchopulmonary dysplasia, congenital heart disease, etc.), and general preventive measures to reduce nosocomial infection with RSV. There is sufficient evidence on the lack of efficacy of inhaled corticosteroids, oral corticosteroids and montelukast. Intravenous RSV immunoglobulin has an unfavorable risk-benefit balance, particularly with the availability of monoclonal antibodies. Palivizumab is effective as preventive treatment of RSV infection in risk populations (high risk preterm infants and hemodynamically significant congenital heart disease), but not in the frequency and severity (ICU admission, need for mechanical ventilation and mortality) of the acute bronchiolitis. The benefits of palivizumab (less admissions) seem to be worth the adverse effects, but we do not know the cost-benefit ratio. The control and prevention measures of nosocomial transmission of RSV infection (isolation, hand washing, use of mask, gloves, cap and shoes) are based on indirect evidence.

[Exhaled nitric oxide in children under 4 years of age with recurrent bronchitis]

BACKGROUND

The objective of the study was to assess bronchial inflammation in preschool children with recurrent bronchitis by measuring exhaled nitric oxide.

PATIENTS AND METHODS

The study included patients under 4 years of age with at least 3 episodes of wheezing in the past year (n=63) and a control group (n=30). Exhaled nitric oxide was measured in samples collected offline during spontaneous tidal breathing with a face mask and stored in Mylar balloons.

RESULTS

The fractional exhaled nitric oxide concentration (FE(NO)) was higher in the group with bronchitis (mean [SD], 5.3 [1.3] parts per billion [ppb]) than in the control group (4.6 [1.1]ppb) (P=.02). There was a significant difference between the control group and children in the bronchitis group not treated with inhaled corticosteroids (P<.05), but not between controls and corticosteroid-treated patients. A relationship with eosinophil count was observed in that those with higher counts (>400 microL) had higher FE(NO) levels (P<.01). No relationship was observed between FE(NO) and a positive methacholine challenge test. Follow-up lasted at least 20 months. The initial FE(NO) level did not differ significantly according to whether patients were subsequently transient, infrequent, or frequent wheezers (5.2 [0.98]ppb, 5.6 [1.5]ppb, and 4.8 [1.34]ppb, respectively; P=.36).

CONCLUSIONS

In children under 4 years of age with recurrent wheezing bronchitis who were asymptomatic at study entry, a small increase in FE(NO) was observed although there was a good deal of overlap with the control group.