Airway hyper-responsiveness and small airway function in children with well-controlled asthma
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Published on: April 13, 2010
Jianfeng Huang1, Mingzhi Zhang1, Xiaobo Zhang1
1Department of Respiratory, Children's Hospital of FuDan University, ShangHai, China.
Insights
Children with well-controlled asthma often have airway hyper-responsiveness (AHR) and impaired small airway function. Even in controlled asthma, reduced small airway function is linked to AHR.
Area of Science:
- Pediatric Pulmonology
- Respiratory Medicine
- Asthma Research
Background:
- Airway hyper-responsiveness (AHR) and small airway function are crucial in pediatric asthma.
- The role of small airways in well-controlled asthma with AHR remains unclear.
Purpose of the Study:
- To assess AHR and small airway function in children with well-controlled asthma.
- To explore the relationship between AHR and small airway function in this population.
Main Methods:
- Compared 116 children with well-controlled asthma (Group A) to 46 healthy children (Group C).
- Utilized spirometry, impulse oscillometry (IOS), and methacholine challenge tests (MCT).
Main Results:
- No significant differences in FEV1 or FEV1/FVC ratio between groups.
- Group A showed significantly lower FEF25-75 and X5 compared to controls.
- 90.5% of Group A were positive to MCT, with lower FEF25-75 in those positive for AHR.
Conclusions:
- AHR is prevalent in most children with well-controlled asthma.
- Children with well-controlled asthma and AHR exhibit poorer small airway function compared to those without AHR.
Background:
Airway hyper-responsiveness (AHR) and small airway function are critical to children with asthma. Little is known about the role of the small airway in well-controlled subjects with AHR. We aimed to evaluate AHR and small airway function in children with well-controlled asthma, and to investigate the association between them.
Methods:
We studied 116 cases of children with well-controlled asthma (group A), 46 cases healthy children as controls (group C). Spirometry, impulse oscillometry (IOS), and methacholine challenge test (MCT) were conducted on all the children.
Results:
(i) Group A and group C had no differences in forced expiratory volume in 1 s (FEV1) and FEV1/forced vital capacity (FVC) ratio (P > 0.05). Forced expiratory flow between 25 and 75% of vital capacity (FEF25-75) and reactance at 5 Hz (X5) in group A were significantly lower than those in group C. (ii) One hundred and five cases (90.5%) of group A proved positive to MCT. (iii) FEF25-75 in group A proved positive to MCT but were lower than those proved negative (P < 0.05).
Conclusion:
AHR persisted in majority of children with well-controlled asthma. Among children with well-controlled asthma, small airway function was lower in those with AHR than those without AHR.
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