Review Question - QID 107347

A 48-year-old man presents to the emergency department for evaluation of shortness of breath. He states that he was hospitalized for osteomyelitis in his right foot requiring amputation two weeks prior. He states that he has had pain and swelling in his left leg over the last two days, and then suddenly developed shortness of breath one hour ago. He denies associated cough or any other symptoms. His past medical history is significant for diabetes mellitus and hypertension. His temperature is 98°F (37°C), blood pressure is 100/70 mmHg, pulse is 130/min, respirations are 27/min, and oxygen saturation is 91% on room air. The left leg appears erythematous and edematous on exam. His amputation stump appears slightly erythematous with no significant swelling or drainage noted. Lungs are clear to auscultation bilaterally. An electrocardiogram is obtained and reveals sinus tachycardia. He requests something to help with his shortness of breath, and is placed on supplemental oxygen. What is the next best step in management?