2. Different methods of high levels of PEEP selection.

Study	Methods of high levels of PEEP selection
Amato 1998	PEEP: 2 cmH₂O > Pflex or 16 cmH₂O if no Pflex If Pflex could not be determined on the pressure–volume curve, an empirical total‐PEEP value of 16 cmH₂O was used
Brower 2004	PEEP/FIO₂ combination (programming with higher levels of PEEP) High PEEP levels according to FIO₂ used
Cavalcanti 2017	Decremental PEEP titration according to best static lung compliance
Hodgson 2011	Recruiting manoeuvres followed by decremental PEEP titration until decrease in SpO₂≥ 1% from maximum SpO₂observed
Hodgson 2019	Recruiting manoeuvres followed by decremental PEEP titration until decrease in SpO₂≥ 2% from maximum SpO₂observed
Kacmarek 2016	Recruiting manoeuvres followed by decremental PEEP titration according to best dynamic lung compliance
Meade 2008	PEEP/FIO₂ combination (programming with higher levels of PEEP) High PEEP levels according to FIO₂ used
Mercat 2008	PEEP level to achieve plateau pressures between 28 and 30 cmH₂O
Talmor 2008	PEEP levels set to achieve transpulmonary pressure of 0 to 10 cmH₂O at end‐expiration
Villar 2006	PEEP 2 cmH₂O > Pflex If Pflex could not be determined on the pressure–volume curve, empirical total‐PEEP value of 15 cmH₂O was used

Pflex: upward shift in slope of the pressure‐volume curve.

Transpulmonary pressure (airway pressure minus pleural pressure): when airway pressure was recorded during MV, and pleural pressure was estimated by an oesophageal balloon catheter.