Figure 2.

Experimental protocol for PEEP titration. Group C, control group with a fixed PEEP of 5 cmH₂O; group O, optimized PEEP group with an individualized PEEP at which SpO₂ was maintained at 95–96% with minimal FiO₂; TV, tidal volume; ETCO₂, end-expiratory carbon dioxide partial pressure; SpO₂, pulse oxygen saturation; RM, recruitment maneuver; PACU, postanaesthesia care unit. PEEP, positive end-expiratory pressure; PaO₂, oxygen partial pressure in arterial blood; FiO₂, fraction of inspired oxygen.