Table 2.

Perioperative ventilatory protocol in each of the two treatment arms

	Conventional ventilation	Open-lung ventilation
Ventilation before CPB	• Tidal volume 6–8 mL/kg PBW • PEEP 2 cmH2O • RR for ETCO2 35–45 mmHg • Lowest FiO2 to maintain SpO2 > 94%. • I:E ratio at 1:2	• Tidal volume 6–8 mL/kg PBW • PEEP 8 cmH2O • RR for ETCO2 35–45 mmHg • Lowest FiO2 to maintain SpO2 > 94% • I:E ratio at 1:2
Systematic recruitment maneuvers	No	Yes
Ventilation during CPB	CPAP 2 cmH2O	Ultraprotective ventilation • Tidal volume 3 mL/kg PBW • PEEP 8 cmH2O • RR 12 cpm • FiO2 40%
Ventilation after CPB (including in ICU)	• Tidal volume 6–8 mL/kg PBW • PEEP 2 cmH2O • RR for ETCO2 35––45 mmHg • Lowest FiO2 to maintain SpO2 > 94% • I:E ratio at 1:2	• Tidal volume 6–8 mL/kg PBW • PEEP 8 cmH2O • RR for ETCO2 35––45 mmHg • Lowest FiO2 to maintain SpO2 > 94% • I:E ratio at 1:2
Protocol deviation	Rescue strategy • Unplanned recruitment maneuver • +/− PEEP increase	Surgical or hemodynamic deviation • Recruitment maneuver interruption • PEEP decrease (1 cmH2O by 1 cmH2O step)

CPB cardiopulmonary bypass, CPAP continuous positive airway pressure, FiO2 inspired oxygen fraction, I:E inspiratory time to expiratory time ratio, PEEP positive end-expiratory pressure, PBW predicted body weight, RR respiratory rate, SpO2 pulse oximetry, ETCO2 end-tidal CO2