A 5-year-old girl is brought to the ENT clinic 4 days after suspected aspiration of a peanut. She has persistent dry cough and mild dyspnoea. Chest X-ray shows hyperinflation of the right lung with mediastinal shift to the left, suggesting a radio-lucent FB in the right mainstem bronchus. She is haemodynamically stable and has adequate oxygen saturation. What is the most appropriate immediate next step?