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Published on: August 7, 2017
Small Airway Dysfunction in Children With Controlled Asthma
Garazi Azaldegi1, Javier Korta2, Olaia Sardón2
1Sección de Neumología Infantil, Hospital Universitario Donostia, San Sebastián, España.
Insights
Children with moderate-severe asthma often have small airway dysfunction even with normal lung function tests. Evaluating small airways did not correlate with asthma control levels in this study.
Area of Science:
- Pediatric Pulmonology
- Respiratory Medicine
- Asthma Research
Background:
- Asthma involves chronic inflammation of the airways.
- Assessing small airway (SA) involvement is crucial for understanding asthma severity.
- Normal FEV1 does not exclude SA dysfunction in children.
Purpose of the Study:
- To evaluate small airway (SA) function in children with moderate-to-severe asthma and normal forced expiratory volume in 1 second (FEV1).
- To identify specific parameters indicative of SA involvement.
- To determine if SA dysfunction correlates with asthma control levels.
Main Methods:
- An observational, cross-sectional study of 100 children with moderate-to-severe asthma and normal FEV1.
- Utilized multiflow FEno (CAno), oscillatory resistance and reactance (R5-R20, X5), spirometry (FEF25-75), body plethysmography (RV/TLC), and bronchodilation tests.
- Defined SA involvement based on established cut-off values for each parameter.
Main Results:
- 77.78% of participants (n=72) showed at least one altered SA parameter.
- 48.61% exhibited two or more altered SA parameters.
- No significant differences in SA parameters were observed between well-controlled and poorly controlled asthma groups.
Conclusions:
- Children with moderate-to-severe asthma and normal FEV1 frequently present with small airway (SA) dysfunction.
- Current SA evaluation techniques in this study did not correlate with asthma control status.
- Further research is needed to understand the clinical implications of SA dysfunction in pediatric asthma.
Introduction:
Asthma is characterized by chronic inflammation of the central and distal airways. The aim of this study was to assess the small airway (SA) of children with moderate-severe asthma with normal FEV1.
Methods:
This was an open-label, prospective, observational, cross-sectional study with consecutive inclusion of patients with moderate-severe asthma, receiving standard clinical treatment, with normal baseline FEV1. We determined multiflow FEno (CAno), oscillatory resistance and reactance (R5-R20, X5), forced spirometry (FEV1, FEF25-75), total body plethysmography (RV/TLC) and bronchodilation test. SA involvement was defined as: CAno>4.5 ppb, R5-R20>0.147kPa/L/s, X5<-0.18kPa/L, FEF25-75<-1.65 z-score, RV/TLC>33%. Poor asthma control was defined as ≤ 19 points on the ACT questionnaire or ≤ 20 on the c-ACT.
Results:
In a cohort of 100 cases, 76 had moderate asthma and 24 had severe asthma; 71 children were classified as poorly controlled and 29 were well-controlled. In total, 77.78% of the group with all the correct determinations (n=72) showed ≥ 1 altered SA parameter and 48.61% ≥ 2 parameters. There were no differences between well-controlled or poorly controlled cases.
Conclusions:
Children with moderate-severe asthma, with normal FEV1, show a phenotype of dysfunctional SA. In our series, the evaluation of SA using the techniques described above did not provide information on disease control.
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