Unilateral expiratory airflow obstruction during forced exhalation.

We present a case of unilateral airflow obstruction during forced exhalations. The patient presented with episodic dyspnea and wheezing, particularly when he lay in the right lateral decubitus position. Spirometry revealed symmetric, marked reductions in forced expiratory volume in the first second and forced vital capacity values, while plethysmography demonstrated a near-normal total lung capacity. Bronchoscopy revealed a polypoid lesion in the right main bronchus, of which biopsy specimens demonstrated adenoid cystic carcinoma. Following a right pneumonectomy, total lung capacity was markedly reduced; interestingly, however, spirometry was essentially unchanged. This case is an elegant illustration of the effects of respiratory maneuvers and body position on airway caliber.