Positional dyspnea and oxygen desaturation related to carcinoma of the lung. Up with the good lung.

Body position can lead to respiratory symptoms and affect gas exchange in disease states. We describe a patient with carcinoma of the left lung in whom dyspnea and oxygen desaturation developed in the right lateral position only. Fiberoptic bronchoscopic study demonstrated a tumor mass protruding into the left main-stem bronchus, which caused further narrowing when the patient turned on his right side.