Participants
Twelve children were included during the study period, and data were obtained from clinical records. The average age at diagnosis was 36 months. All patients were diagnosed with PIBO according to a history of severe lower respiratory infection or acute lung injury in previously healthy subjects; exercise intolerance, recurrent or persistent wheezing, coughing and tachypnea with extensive wheezing and moist crackles in lungs lasting for more than 6 weeks; severe obstructive lung disease on PFTs; characteristic changes of mosaic perfusion pattern, bronchial wall thickening, bronchial dilation and vascular attenuation on chest HRCT[6]; bronchopulmonary dysplasia, cystic fibrosis (CF), pulmonary tuberculosis, immunodeficiency and congenital heart disease were excluded on the basis of clinical, radiological and laboratory data. We followed their PFT results since they were able to perform the spirometry maneuver until November 2019. The average time was 29 months (range of 6-80months) for follow-up of PFTs.