Effect of CPAP on airway reactivity and airway inflammation in children with moderate-severe asthma

Abstract

Background and objective: Asthma is characterized by airway hyperreactivity and airway inflammation. We previously demonstrated that adults with mild well-controlled asthma exhibited a marked decrease in airway reactivity (PC20 increased >2-fold) after using nocturnal continuous positive airway pressure (CPAP) for 1 week. If CPAP produces a similar suppression of airway reactivity in children with moderate-severe asthma, who require chronic use of corticosteroids, then this non-pharmacological therapy might provide a beneficial alternative or supplemental therapy in these subjects.

Methods: Children aged 8-17 years with moderate-severe asthma were treated with 4 weeks of nocturnal CPAP (8-10 cm H₂ O) or sham CPAP (<2 cm H₂ O). Adherence was monitored with a modem installed in the equipment or by memory cards. Airway reactivity, assessed by methacholine bronchial challenge, was measured prior to and following treatment.

Results: The percentage of subjects adherent to treatment was similar in both groups (19/27 CPAP vs 19/28 sham, ~70%). There was a tendency for PC20 to increase with treatment in both groups (3.0-5.3 mg/mL CPAP vs 3.2 to 4.3 mg/mL sham, P = 0.083); however, the change did not differ significantly between groups (P = 0.569).

Conclusion: We found that the 4-week treatment with nocturnal CPAP did not produce a twofold suppression of airway reactivity in children with moderate-severe asthma.

Trial registration: ClinicalTrials.gov NCT02396849.

Keywords: bronchial challenge; chronic mechanical strain; induced sputum; lung function.

Figure 1

Airway reactivity (PC20) at visit 1 and visit 2 for continuous positive airway pressure (CPAP; , n = 26) and (sham; , n = 27) treated groups. There was no significant difference between treatment groups in baseline PC20 (P > 0.5). Both groups tended to have an increase in PC20 (lower airway reactivity) between visit 1 and visit 2, which was not significant (P = 0.083). While there was a tendency for greater increase in PC20 in the CPAP-treated group compared to the sham-treated group, the interaction term was not significant (P = 0.569). Plots represent mean and SE.

Figure 2

Percentage of sputum eosinophils at visit 1 and visit 2 for continuous positive airway pressure (CPAP; , n = 10) and (sham; , n = 12) treated groups. There was no signifi-cant difference between groups in baseline % sputum eosinophils (P > 0.5). While there was a tendency for % sputum eosinophils to decrease in the CPAP group and increase in the sham group between visit 1 and visit 2, the interaction term was not significant (P = 0.130). Plots represent mean and SE.