Greetings.
It is quite serious problem and may cause pneumonitis. Although, barium is inert (non irritating) material still, it can cause alveolar shunts, infiltration and resultant hypoxemia (low blood oxygen levels). Bronchoscopy is performed to remove the barium. The prognosis would be dependent on the amount of barium inserted.
Hope this helps.
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Dr. Arun
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