Lung function assessment in preschool children with symptoms of asthma: A preliminary study

Background: Asthma causes a significant disease burden in children and it is objectively diagnosed by demonstration of reversible airway obstruction. However, objective diagnosis of airway obstruction in preschool children with asthma symptoms is not frequently practised in Sri Lanka.Methodology: This study was a descriptive cross-sectional preliminary study conducted in a convenience sample of 11 consecutive children aged 3-6 years presenting with symptoms of asthma. Asthma Control Test (ACT) was used to assess symptom control. Lung function assessment was carried out using spirometry and impulse oscillometry (IOS) according to European Respiratory Society and American Thoracic Society guidelines. Airway obstruction cut-off was considered as the forced expiratory volume in the first second (FEV1): forced vital capacity (FVC) ratio less than 0.9.Results: The study sample consisted of 4 boys and 7 girls. Nine participants had good control of asthma symptoms (ACT>19). Only three participants performed spirometry in an acceptable and reproducible manner and two of them demonstrated evidence of airway obstruction. FVC less than 0.8 was noted in two participants probably attributable to poor effort (pseudo-restriction). Significant bronchodilator reversibility was not demonstrable in any patient, and two participants had reduced FEV1:FVC ratio following administration of beta-2-agonists probably due to paradoxical bronchoconstriction or improvement of FVC.IOS assessment was completed successfully by seven children. Increased R5-20 was detected in 3 participants and increased resonance frequency in another two children, suggesting probable peripheral airway involvement.Conclusion: Airway obstruction in preschool children could be assessed using spirometry and IOS. IOS is more feasible in preschool children.