Ventilation heterogeneity in children with severe asthma

Small airway disease, characterised by ventilation heterogeneity (VH), is present in a subgroup of patients with asthma. Ventilation heterogeneity can be measured using multiple breath washout testing. Few studies have been reported in children. We studied the relationship between VH, asthma severity, and spirometry in a cross-sectional observational cohort study involving children with stable mild-moderate and severe asthma by GINA classification and a group of healthy controls. Thirty-seven participants aged 5-16 years completed multiple breath nitrogen washout (MBNW) testing (seven controls, seven mild-moderate asthma, 23 severe asthma). The lung clearance index (LCI) was normal in control and mild-moderate asthmatics. LCI was abnormal in 5/23 (21%) of severe asthmatics. The LCI negatively correlated with FEV(1)z-score. Conclusion: VH is present in asthmatic children and appears to be more common in severe asthma. The LCI was significantly higher in the cohort of children with severe asthma, despite no difference in FEV1 between the groups. This supports previous evidence that LCI is a more sensitive marker of airway disease than FEV1. MBNW shows potential as a useful tool to assess children with severe asthma and may help inform clinical decisions.

Automated summary

The study found that ventilation heterogeneity is present in children with asthma, particularly in severe cases. Although there was no difference in FEV1 between groups, the lung clearance index (LCI) was significantly higher in children with severe asthma, suggesting that it may be a more sensitive marker for airway disease. This indicates that multiple breath nitrogen washout testing has the potential to be a useful tool in assessing severe asthma in children and guiding clinical decisions.