Twenty minutes ago at school, eight-year-old Brian ate what he thought was a butterscotch cookie. It turns out it was made from peanut butter, and Brian has a history of peanut allergy. He is brought in by a basic life support ambulance and is complaining of severe itching. He's screaming, “It's hard to breathe!” Vital signs: Blood pressure 90/40 mm Hg, heart rate 120 beats per minute, respiratory rate 30 breaths per minute, and he is afebrile. On exam, he is covered head-to-toe in hives and has audible wheezing on chest auscultation. His oropharynx is clear, but he's not looking good … how do you proceed?