PD08 - Measuring direct and indirect airway hyperresponsiveness in young children with obstructive symptoms
© Kalliola et al; licensee BioMed Central Ltd. 2014
Published: 28 February 2014
Airway hyperresponsiveness (AHR) is a key feature of asthma. AHR with asthma may begin already in infancy and can be assessed by direct and indirect bronchial challenges. Most young children are not able to perform maneuvers required for spirometry but can satisfactory perform impulse oscillometry (IOS) which needs minimal cooperation.
To compare bronchial challenge tests by mannitol, methacholine and exercise with oscillometric technique in young children with obstructive symptoms.
A total of 121 children (3.7-8.1 yr) were studied (31 with troublesome lung symptoms (TLS), 15 with bronchopulmonary dysplasia (BPD), 61 with history of early wheezing disorder and 14 healthy controls) to assess AHR by exercise test, mannitol and methacholine challenges with IOS. If the child used asthma control medication, it was stopped four weeks before the lung function tests. Tests were performed in separate days within two weeks period. AHR to exercise was defined as a ≥ 35 % increase in Rrs5. For mannitol and methacholine challenges, the dose causing an increase of 40 % in Rrs5 (PD40Rrs5) was calculated.
Mannitol challenge did not distinguish the study groups of young children with obstructive lung symptoms. Methacholine test is easy to perform with IOS, shows concurrent results with exercise challenge and may thereby offer a practical aid for evaluation of troublesome lung symptoms in young children.
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