A 48-year-old man presents to the clinic complaining of progressive shortness of breath over the past six months. He reports that his breathing difficulties worsen significantly when he sits upright or stands, and they improve when he lies down. He states, “I feel like I cannot get enough air unless I am flat on my back.” His past medical history is significant for alcohol-related chronic advanced liver disease, diagnosed three years ago, which is currently compensated. He quit drinking alcohol three years ago. He denies any chest pain, cough, orthopnea, or lower extremity swelling.

He appears chronically ill and mildly dyspneic while seated. He is afebrile. His blood pressure is 110/70 mmHg with a regular heart rate of 92 beats per minute, and his respiratory rate is 22 breaths per minute. His oxygen saturation on room air is 96 percent while supine, but drops to 89 percent upon standing.