Interrupter resistance changes in children with bronchiolitis.

INTRODUCTION Determination of lung function in children younger than three years with bronchiolitis may aid in treatment; however, technical difficulties such as requirement of sedation and lack in standardization limit clinical use. OBJECTIVES Aim of this study was to evaluate lung function changes using the interrupter technique in unsedated wheezing children younger than 3 years during and after acute bronchiolitis. METHODS Children with acute bronchiolitis younger than three years age were enrolled in this cohort study. Number of previous bronchiolitis episodes, severity of pulmonary findings, duration of acute bronchiolitis findings before presentation, requirement for hospitalization were recorded during initial enrollment. Duration of the current bronchiolitis was recorded. Interrupter resistance (Rint) measurements were performed on all children during and after bronchiolitis, using a face mask. RESULTS Mean (+/-SD) age of the children enrolled was 9.4 +/- 2.9 months. Mean bronchiolitis score was 5.6 +/- 1.4 at presentation. Mean duration of acute bronchiolitis before and after presentation were 10.1 +/- 13.0 and 5.1 +/- 2.3 days, respectively. There was a significant decrease in expiratory Rint values after clinical bronchiolitis findings terminated [1.08 (0.45) vs. 0.80 (0.33) kPa.L-1.s, p = 0.009]. Flow had not changed significantly while mouth pressure had decreased (p = 0.96 and p = 0.01, respectively). CONCLUSION Interrupter technique measurements showed higher resistance during acute bronchiolitis in children, which decreased after acute findings, disappeared. Rint may be used as a method to detect the change in airway function in unsedated children younger than three years in ambulatory conditions, despite some limitations of standardization in this age group.