Ventilation heterogeneity in children with severe asthma

Abstract

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 FEV1z-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. What is Known:• Increased ventilation heterogeneity is present in some children with asthma• Spirometry is not sensitive enough to detect small airway involvement in asthma What is New• Lung clearance index is abnormal in a significant subgroup of children with severe asthma but rarely in children with mild-moderate asthma• Our data suggests that LCI monitoring should be considered in children with severe asthma

Clinical characteristics and diagnostic workup in severe asthma: data from the database of the Italian Pediatric Respiratory Society

“…The mean values of spirometric parameters (FEV1, FEV/FVC, FEF25-75) were within the normal range, and only in about one-third of the cases FEV1 values were below 80% of predicted. This result, which might be partly due to long term treatment with biologics in some of the children, is consistent with previous studies showing that spirometry is often normal in pediatric severe asthma, while other tests, such as lung clearance index, can show an earlier deterioration (15).…”

Bronchiolitis hospital admission in infancy is associated with later preschool ventilation inhomogeneity

“…While the magnitude of LCI and S cond changes observed is small and their clinical importance remains to be determined, it is possible that even small changes could have functional relevance. For instance, we and others have also shown that LCI is elevated, although mildly only, in many severe asthmatics as compared with those without severe asthma 43,44 . Several studies have also examined the utility of MBW in preschool asthma, and some 45,46 but not all 47 studies reported higher LCI values with an asthma diagnosis, compared with healthy controls.…”

“…For instance, we and others have also shown that LCI is elevated, although mildly only, in many severe asthmatics as compared with those without severe asthma. 43,44 Several studies have also examined the utility of MBW in preschool asthma, and some 45,46 but not all 47 studies reported higher LCI values with an asthma diagnosis, compared with healthy controls.…”

Place of nebulizer therapy in the treatment of bronchial asthma in children

“…• Даже при нормальном значении ОФВ1 у каждого пятого пациента с тяжелой БА снижается индекс легочного клиренса, что свидетельствует о дисфункции малых дыхательных путей, т. е. неоднородной вентиляции периферических отделов [25][26][27].…”