Chest
Original Research: AsthmaAbnormal Small Airways Function in Children With Mild Asthma
Section snippets
Study Population
We enrolled 70 children aged 6 to 16 years from an asthma outpatient clinic and a healthy volunteer database at the Children's Hospital Bern. Children with asthma were eligible if they had a history of controlled mild asthma (daytime symptoms ≤ 2 d/wk), normal FEV1 ± 1.96 z scores, a prescription for low to moderate inhaled corticosteroid doses (≤ 200 μg/d fluticasone or equivalent), and no history of increased use of asthma medication during the previous 6 months.25 Healthy children had no
Results
Sixty-six children (31 with asthma) were studied, and 561 tidal SBW tests were achieved. Twenty-one children with asthma (67%) were atopic, and 22 (71%) received inhaled corticosteroids in the previous month. Healthy control subjects and children with asthma were comparable regarding age, height, weight, and sex (Table 1).
Children with mild asthma had significantly increased acinar ventilation heterogeneity (Figs 1–3, Table 2). SDTG was abnormal (≤ −2 z scores) in 11 children with asthma (36%)
Discussion
Ventilation heterogeneity is increased in children with mild asthma despite rare symptoms and normal FEV1. More than one-third of children with asthma had abnormal SDTG findings, suggesting impaired small airways function in the acinar lung region. Measures of global ventilation heterogeneity (SN2) and airways obstruction (FEF25%-75%) are normal in the majority of children with mild asthma. sRaw is elevated on average but is only weakly associated with ventilation heterogeneity. Administration
Acknowledgments
Author contributions: Dr Latzin had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.
Dr Singer: contributed to the study concept and design; data acquisition, analysis, and interpretation; and drafting, critical revision for important intellectual content, and final approval of the manuscript.
Dr Abbas: contributed to the study concept and design; data acquisition, analysis, and interpretation; and drafting,
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Cited by (33)
Persistent Asthma from Childhood to Adulthood Presents a Distinct Phenotype of Adult Asthma
2020, Journal of Allergy and Clinical Immunology: In PracticeCitation Excerpt :Because %FEF75, %FEF50, and %FEF25-75 are all used as markers for small airway dysfunction,17-19 these results suggest that the impairment of the small airways was greater in the persistent group than the other 2 groups, which is in agreement with a previous report.13 The reason for this is unclear, but small airway diseases seem to be present despite mild asthma symptoms and normal spirometry in children with asthma,20 implying that the small airways of children may be more fragile and sensitive to airway inflammation. Small airway dysfunction in patients with asthma is also associated with airway hyperresponsiveness21 and is strongly related to an increase in dyspnea,22 which indicates that the small airway asthma phenotype may be associated with severer asthma.18,23,24
Recognition of the peripheral airway impairment phenotype in children with well-controlled asthma
2018, Annals of Allergy, Asthma and ImmunologyCitation Excerpt :Although FEF25%-75% has been shown to be more reflective of the peripheral airways than FEV1, several studies suggest that it is predominantly a measure of a combination of both central and peripheral airways.10,28 In that regard, Singer et al28 found that although 36% of 31 patients with well-controlled asthma had peripheral airway impairment by increased acinar ventilation heterogeneity with inert gas washout, only 10% had abnormal FEF25%-75%,28 supporting our current findings. A number of studies have previously reviewed reported that in comparison with non–extra fine inhaled corticosteroid (ICS), the smaller particle aerosol consistently decreases peripheral airway obstruction shown by several biomarkers, including IOS.19
The applicability of inert gas washout method in pulmonary function testing in chidren
2017, Pediatria PolskaManifesto on small airway involvement and management in asthma and chronic obstructive pulmonary disease: an Interasma (Global Asthma Association - GAA) and World Allergy Organization (WAO) document endorsed by Allergic Rhinitis and its Impact on Asthma (ARIA) and Global Allergy and Asthma European Network (GA2LEN)
2016, World Allergy Organization JournalCitation Excerpt :The detection of an abnormal forced expiratory flow (FEF25–75) should be supported by other pulmonary function tests (impulse oscillometry, whole-body plethysmography, exhaled-breath nitric oxide, and single-breath and multiple-breath nitrogen washout) to confirm a diagnosis of small airway dysfunction [4, 10–12]. The small airways play a role in the pathobiology of asthma and, although they are involved in half of all cases of asthma, they can have a distinct role in specific disease phenotypes [13–17]. Inflammatory changes involving the small airways influence the severity of asthma [18–23].
Drs Singer and Abbas contributed equally to this work.
Funding/Support: This work was funded by the Federal Department of Economic Affairs Switzerland, Commission for Technology and Innovation, Innovation Promotion Agency [unrestricted educational grant 14435.1 PFLS-LS] and the Julia Bangerter-Rhyner Foundation.
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