Croup vs Epiglottitis vs Bacterial Tracheitis

A 4-year-old unvaccinated child presents to the emergency department with acute onset of severe throat pain, drooling, and difficulty swallowing over the past 4 hours. On examination, the child is sitting upright, leaning forward with mouth open, and appears toxic. The structure marked **B** in the diagram is suspected to be acutely inflamed. Which of the following is the MOST appropriate immediate management step?