Postural Effect on Regional Ventilation

Abstract

Postural effects on regional ventilation were studied in nine normal subjects using radioactive xenon gas. Two scintillation detectors were mounted on two precordial spots on the right and left lungs, and regional ventilation was assessed on the same spots in the supine position and the right and left lateral decubitus positions.
Regional total lung capacity (TLCr) and regional turn-over rate increased in the dependent lung in the lateral decubitus positions, whereas regional functional residual capacity (FRCr) decreased in the dependent lungs. Regional 50% wash-out time was always shorter in the dependent lung than that in the superior lung, although there was no appreciable difference in the right and left lungs in the supine position.