Table 1. Characteristics of the five largest randomised controlled trials testing the role of prone positioning in patient survival

	First author [ref.]
	Gattinoni [31]	Guérin [32]	Mancebo [33]	Taccone [34]	Guérin [2]
Patients n
Supine position	152	378	60	174	229
Prone position	152	413	76	168	237
Patients with ARDS %
Supine position	93.3	28	100	100	100
Prone position	94.7	33.9	100	100	100
P_aO₂/F_IO₂ at inclusion mmHg	127	150	147	113	100
Tidal volume at inclusion mL·kg⁻¹	10.3 MBW	8 MBW	8.4 PBW	8 PBW	6.1 PBW
PEEP at inclusion cmH₂O	10	8	12	10	10
Prone position session duration^# h	7	8	17	18	17
Mortality %
Supine position	25	31.5	58	32.8	32.8
Prone position	21.1	32.4	43	31	16

ARDS: acute respiratory distress syndrome; P_aO₂: arterial oxygen tension; F_IO₂: inspiratory oxygen fraction; PEEP: positive end-expiratory pressure; MBW: measured body weight; PBW: predicted body weight. ^#: average hours per session.