Lung function measurements in children - copsac

Acute severe wheezy exacerbations
Acute severe wheezy exacerbations was defined as an acute obstructive respiratory
illness diagnosed by the COPSAC clinical research unit doctor and judged to be a
severity requiring treatment with oral or high-dose inhaled corticosteroids (>800 micg
budesonide/day) or hospitalizations at their local hospital caused by airway symptoms
where an anti-asthmatic drug was prescribed (pseudocroup episodes were excluded).
Control group
Children who developed neither bronchiolitis nor acute wheezy exacerbations before
age 2 were considered as controls.
Lung function measurements
Study II:
Whole bodyplethysmography
Children less than 7 years were tested using the whole body plethysmography to
measure specific airway resistance (sRaw) as previously detailed (10, 11).
Spirometry
Children of 7 years and above used a spirometer to measure Forced Expiratory Volume
in the first second (FEV 1 ) (Vitalograph Spirotrac) according to the criteria of the
American Thoracic Society (130).
Bronchial responsiveness
Children of 7 years and above were tested for responsiveness to methacholine chloride
with FEV 1 measurements before and 3 minutes after each dose. Methacholine was
delivered in successively increasing doses according to a protocol previously validated
for school children (33) by an automatic, inhalation synchronized, dosimetric jetnebulizer
(Spira Elektro 2; Respiratory Care Center, Hämeenlinna, Finland). PD20
value (mol) was calculated by linear interpolation between the dose points bracketing
the 20% fall in FEV 1 (131).
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