Review Question - QID 210707

A 62-year-old patient presents to the emergency department during the winter for an episode of shortness of breath and a productive cough. The patient is homeless, has had multiple sick contacts, and has presented to the hospital previously for repeated episodes of pancreatitis. The rest of his medical history is not well known. His temperature is 97.6°F (36.4°C), blood pressure is 147/98 mmHg, pulse is 120/min, respirations are 24/min, and oxygen saturation is 80% on room air. A chest radiograph is obtained as seen in Figure A. Cardiopulmonary exam reveals tachycardia and poor air movement bilaterally. A musculoskeletal exam reveals scars in the patient's antecubital fossa. Which of the following is the most appropriate next step in management?