Positional Effects on the Distributions of Ventilation and End-Expiratory Gas Volume in the Asymmetric Chest-a Quantitative Lung Computed Tomographic Analysis

Body positioning affects the configuration and dynamic properties of the chest wall and therefore may influence decisions made to increase or decrease ventilating pressures and tidal volume. We hypothesized that unlike global functional residual capacity (FRC), component sector gas volumes and their corresponding regional tidal expansions would vary markedly in the setting of unilateral pleural effusion (PLEF), owing to shifting distributions of aeration and collapse as posture changed.