A 16-year old boy with a history of asthma presents to the ED with severe shortness of breath and audible wheezing. He uses an inhaled corticosteroid and a long acting beta-2-agonist at home daily. However, he has had to use his short acting beta-2-agonist roughly every hour for the past day. In the ED, his vital signs are BP 114/72, HR 106, RR 28, oxygen saturation 94% on room air, and temperature 99.0°F. Diffuse wheezing is appreciated and intercostal retractions are observed.