Lung function measurements in children - copsac

Abstract
Background: Two-three percent of infants react with acute bronchiolitis in association with Respiratory
Syncytial Virus (RSV) infection. It has been suggested that such exaggerated response to a
common infection is due to pre-existing abnormal pulmonary function.
Aim: We aimed to compare prospectively the baseline lung function and bronchial responsiveness
in newborns that later develop RSV bronchiolitis with those who do not develop such severe infection
within the first 2 years of life.
Method: Spirometry was measured at one month of life by the infant spirometry and bronchial responsiveness
to increasing doses of metacholine was determined in a prospective birth cohort study
of 411 infants of asthmatic mothers.
Results: 22 infants in the cohort developed RSV bronchiolitis before age 2 (mean age 8 months).
Children with and without RSV bronchiolitis did not differ significantly in baseline lung function
(logFEV 0.5 ), odds ratio (OR) estimate [CI 95%] 1.08 [0.09-13.6]; p=0.5 or bronchial responsiveness
to metacholine (logPD 15 TcO 2 ) OR [CI 95%] 0.94 [0.74-1.20]; p= 0.64.
Conclusion: Neither baseline lung function nor bronchial hyperresponsiveness in newborns were
predictive of later development of RSV bronchiolitis (though the confidence limit of this comparison
was wide). Our findings suggest an environmental exposure or genetic disposition rather than
congenital mechanical difference as the distinguishing feature in children who develop RSV bronchiolitis.
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