Ms. T, an 18-year-old female from Missouri with cystic fibrosis, has been in southern California for 2 months. She was visiting Universal Studios in Los Angeles in January when she developed shaking, chills, fever and confusion and was brought to the hospital emergency department by her sister. She was hypotensive, dyspneic, tachypneic and hypoxemic with an SpO2 of 83% on room air. She denies cough or sputum production. What are the first priorities for treatment and why?