Objective: To explore the application of bronchoscopy in children with protracted bacterial bronchitis (PBB). Methods: The clinical data of 50 hospitalized children diagnosed with PBB were retrospectively analyzed

who admitted to the Department of Respiratory of Children's Hospital of Chongqing Medical University from September 2016 to September 2020. Bronchoscopy was performed on all cases. Results: Among the 50 PBB children

the age ranged from 6 months and 8 days to 12 years and 8 months

with an average age of (55.1±33.0) months

including 4 cases (8.0%) less than 1 year old

12 cases (24.0%) between 1-3 years old

24 cases (48.0%) between 3-7 years old

9 cases (18.0%) between 7-12 years old

and 1 case (2.0%) older than 12 years old. In addition to chronic wet cough

the children with wheezing accounted for 50.0%. All the 50 cases were examined by bronchoscopy and culture of bronchoalveolar lavage fluid (BALF). Bronchoscopy showed a chronic endobronchial inflammation. There were 24 cases with large amount of white secretions

22 cases with large amount of yellow secretions

3 cases with little white secretions

and 1 case with phlegm thrombus. The neutrophil ratio of bronchial alveolar lavage fluid fluctuated between 5% and 94%. There were 26 positive cases in both sputum culture and BALF culture

and the positive rate was 52.0%. The main pathogens were Haemophilus influenzae and Streptococcus pneumoniae. The therapeutic drug was mainly amoxicillin clavulanate potassium and the third-generation cephalosporin. Twenty patients adjusted the use of antibiotics according to their clinical symptoms

bronchoscopic manifestations and BALF culture results. At the same time

17 children were re-hospitalized for multiple bronchoscopic lavage. Individual children chose to improve next generation sequencing (NGS)

mucosal biopsy and total exome gene detection to determine the etiology. Conclusion: PBB is commonly seen in toddler and pre-school age

characterized by persistent wet cough

and easy to be accompanied by wheezing. Bronchoscopy shows chronic endobronchial inflammation changes and more secretions. The specificity and sensitivity of BALF culture can guide the treatment of antibiotics

while NGS

mucosal biopsy and total exome gene detection can be used to assist in the diagnosis and treatment of children with unknown pathogen and poor therapeutic effect. Bronchoscopy combined with antibiotics in the treatment of PBB

can improve the therapeutic effect and prognosis

which has high clinical application value.