Limitations
Follow-up of all participants could not be completed due to the COVID pandemic. A Uniform sequence of first doing IPFT and then doing bronchoscopy could not be done in all patients as there are fixed days for bronchoscopy to avoid discomfort to the patient (additional hospital visit). However, the reporting IPFT and bronchoscopy were done without knowing the results of other procedures. Controls were taken from a birth cohort, and we didn’t perform bronchoscopy on them (gold standard to diagnose airway anomaly). We could not do IPFT of children who had normal bronchoscopy.