Orthopnea is best described as dyspnea that occurs when a patient:

• A. Lies flat
• B. Stands upright
• C. Exercises vigorously
• D. Sleeps on an incline

Answer: (A)

Orthopnea describes dyspnea that occurs when a person lies down. When you lie flat, venous return to the heart increases, which can raise pulmonary pressures and cause fluid to back up into the lungs, making breathing harder. Sitting up or sleeping with the head elevated reduces venous return and pulmonary congestion, easing the breathlessness. That’s why this description fits the scenario of trouble when lying flat. Standing upright, exercising, or sleeping on an incline don’t define orthopnea in the same way, though an incline might relieve symptoms differently.