A comparison of single breath and re-breathe diffusing capacity in emphysema patients and controls

► Single breath diffusing capacity is the recommended measure of lung diffusion in all patients. ► Underestimation of alveolar volume in a single breath maneuver has been demonstrated in emphysema subjects compared with the re-breathe maneuver. ► We demonstrate that the single breath maneuver similarly results in a progressively lower diffusing capacity in emphysema subjects compared with the re-breathe maneuver as spirometry-measured airflow obstruction increases.