Small Airway Dysfunction in Children With Controlled Asthma
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Published on: August 7, 2017
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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