Final answer:
Dexamethasone is the medication that should be administered for severe cases of croup with imminent respiratory failure. It helps to reduce airway inflammation and improve breathing.
Step-by-step explanation:
In severe cases of croup with imminent respiratory failure, the medication that should be administered is dexamethasone. Dexamethasone is a steroid medication that helps to reduce airway inflammation and improve breathing. It is typically given as a single dose, either orally or intravenously, and has been shown to be effective in reducing the severity of symptoms and preventing respiratory failure.