Cardiogenic oscillations in expired nitrogen and regional alveolar hypoventilation

Abstract

The plateau of the single-breath nitrogen curve shows rhythmic oscillations in the concentration of nitrogen. In the present study, the mechanisms involved in the genesis of these oscillations were investigated by varying the composition of the inspired gases and by different respiratory maneuvers. The oscillations were shown to be altered in a characteristic and predictable way in subjects with particular diseases of the heart and lungs. The conclusion is reached that these oscillations represent a combination of uneven alveolar ventilation and vascular impacts; however, the ‘poorly ventilated’ areas are thought to be located in the parahilar, rather than in the peripheral, regions of the lung. Submitted on January 4, 1960