Fig. 1. Time course of end-expiratory lung volume (EELV) for airway pressure release ventilation (APRV) with and without spontaneous breathing (SB) measured by nitrogen (N²) washout and after 4 h of specific treatment using computed tomography (CT) densitometry. **P < 0.01 and ***P < 0.001 compared with Lung Injury. #P < 0.05 APRV with versus  without SB measured by nitrogen washout. §§§P < 0.001 APRV with versus  without SB determined by CT analysis.