Lung function measurements in children - copsac

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Lung function test
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 (19).
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Children less than 7 years were tested using the whole body plethysmography to measure
specific airway resistance (sRaw) as previously detailed (20, 21). We used the MasterScreen
Body Unit Software JLAB (E. JAEGER GmbH, Wuerzburg, Germany).
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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
(22) by an automatic, inhalation synchronized, dosimetric jet-nebulizer (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 (23).
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Children less than 7 years were tested with dry-air hyperventilation as previously described
and validated in this age-group (24, 25).
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Fractional exhaled nitric oxide
Fractional exhaled nitric oxide (F E NO) was measured by the online single breath method
according to European Respiratory Society/American Thoracic Society task force (26) using
the NIOX equipment (Nitric Oxide Monitoring System; Aerocrine, Sweden).
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