Respiratory reactance in children aged three to five years with postinfectious bronchiolitis obliterans is higher than in those with asthma.

AIM: We investigated airway function in preschoolers with postinfectious bronchiolitis obliterans (PIBO) using impulse oscillometry (IOS).

METHODS: This study enrolled 182 children aged three to five years: 12 with PIBO, 135 with asthma and 35 nonatopic controls. Respiratory resistance and reactance were assessed using IOS.

RESULTS: The percentage predicted (% predicted) of prebronchodilator respiratory resistance at 5 Hz was significantly higher in children with PIBO (177.9 ± 118.4%) than the asthma (126.1 ± 30.5%, p = 0.013) or control (121.1 ± 21.8%, p = 0.014) groups. After bronchodilator use, children with PIBO did not reach the values of Rrs5% predicted in the asthma and control groups. Respiratory reactance (Xrs5% predicted) in children with PIBO (337.1 ± 478.5%) was significantly higher than both asthma (130.0 ± 80.0%, p = 0.004) and control (105.1 ± 30.8%, p < 0.001) groups before bronchodilator use and significantly higher than the two groups after bronchodilator use (p = 0.010 and p = 0.004, respectively). The changes in Rrs5 and Xrs5 were not significantly different between the children with PIBO and asthma.

CONCLUSION: Measuring Rrs5 and Xrs5 before and after bronchodilator use may help to discriminate PIBO from asthma in children aged three to five years with chronic or recurrent respiratory symptoms.