A 68-year-old man is brought to the emergency department with a 4-hour history of hemoptysis and shortness of breath at rest. He has no prior history of similar symptoms. There is no history of orthopnea or paroxysmal nocturnal dyspnea. He has had hypertension for over 6 years, with good control on ramipril alone. One year ago, he was diagnosed with small cell lung cancer, following an extensive workup after he presented with unexplained right calf pain and swelling. He is currently on chemotherapy with cisplatin and etoposide. His temperature is 36.5^oC (97.7^oF), pulse is 114/min, respirations are 36/min and blood pressure is 110/70 mm Hg. Pulse oximetry on room air shows an oxygen saturation of 93%. Auscultation of the chest reveals normal breath sounds and a loud P2. A posteroanterior chest x-ray done on presentation was normal. An ECG is only significant for sinus tachycardia.

Which of the following is the most appropriate next step in management?