INTERRUPTER RESISTANCE IN PRESCHOOL CHILDREN: CLINICAL UTILITY IN ASTHMA MANAGEMENT

Asthma is the most common chronic disease affecting children in industrialized countries but it is greatly underdiagnosed in preschool children. In these patients, who are not able to collaborate in the execution of spirometry tests, it is possible to use interrupter resistance (Rint) technique. The aim of our study is to assess Rint utility in asthma management when integrated with clinical evaluation in preschool children. Data from 35 preschool children with recurrent wheezing and/or cough were collected. Case history, physical examination, in vitro and in vivo allergy testing were investigated. According to the presence or absence of symptoms in intercritical period they were divided into two groups, asymptomatic (A) and symptomatic (B). To assess respiratory function we used baseline and post-bronchodilator Rint. In group A (asymptomatic) baseline Rint was normal in 78,9% of children and increased in 21,1%. After bronchodilator (BD) administration there was a significant response in 52,6% of patients. In group B (symptomatic) baseline Rint was normal in 81,3% of children and increased in 18,7%. After bronchodilator administration there was a significant response in 56,3% of patients. Our results confirm that baseline Rint cannot be used to discriminate between healthy and sick children, therefore it is necessary to perform this test after administration of BD. In our patients, a significant response to BD permitted to objectify the discomfort of symptomatic children and to report a state of subclinical bronchial obstruction and/or bad perceptions of the severity of bronchospasm in asymptomatic ones, allowing to confirm previous therapeutic choices in some cases and to suggest different therapeutic strategies in others. Therefore, bronchodilator response measured by Rint should be systematically studied and further assessed in conjunction with clinical outcomes, in order to implement asthma management in children unable to produce reliable spirometry.