Fig. 24.4.

Computed tomography scans of two patients with ARDS, both with a low value of respiratory compliance measured at the bedside: ~30 mL/cmH₂O. In patient A, a set inspiratory pressure will distribute fairly uniformly, moving a small tidal volume and likely recruiting some lung over the tidal insufflation. In patient B, the same pressure will deliver a similar tidal volume (same compliance), but recruitment may be minimal, because the majority of lung tissue, particularly the massive consolidation in the right lung, may not inflate at all, while the seemingly healthy lung that will receive the pressure may have no alveolar unit to recruit and may become overdistended during the tidal insufflation