Table 1:

Characteristics of randomized controlled trials included in the systematic review^*

Study	Patient characteristics at baseline						Details of prone positioning		Protective lung ventilation^† mandated

	No. of patients	Enrolment criteria	Mean Pao₂/Fio₂ ratio, mm Hg	Mean PEEP, cm H₂O	Mean Fio₂, %	Duration of ARDS before enrolment	Mean duration	Criteria for discontinuation
Guérin et al.,17 2013	474	ARDS^‡ with Pao₂/Fio₂ ratio < 150 mm Hg, PEEP ≥ 5 cm H₂O and Fio₂ ≥ 60% after stabilization period of 12–24 h	100	10	79	< 36 h	17 h daily for 4 d	PaO₂/Fio₂ ratio ≥ 150 mm Hg, PEEP ≤ 10 cm H₂O and Fio₂ ≤ 0.6	Yes

Taccone et al.,14 2009	344	ARDS^‡ with PEEP ≥ 5 cm H₂O	113	10	72	< 72 h	18 h daily for 8.3 d	Fio₂ ≤ 40% and PEEP ≤ 10 cm H₂O	Yes

Fernandez et al.,34 2008	42	ARDS^‡	118	11	85	< 48 h	18 h daily^§	Pao₂/Fio₂ ratio > 250 mm Hg and PEEP ≤ 8 cm H₂O for 12 h	Yes

Chan et al.,35 2007	22	ARDS^‡ secondary to community-acquired pneumonia	109	13	88	< 72 h	24 h daily for 4.4 d	Spo₂ > 90%, Fio₂ < 60% for > 24 h (after 72 h)	Yes

Mancebo et al.,36 2006	142	ARDS^‡ with infiltrates in 4 quadrants on chest radiograph	105	7	82	< 48 h	17 h daily for 10.1 d	Fio₂ ≤ 45% and PEEP ≤ 5 cm H₂O	No

Curley et al.,37 2005	102 children (age 2 wk–18 yr)	Acute lung injury or ARDS^‡	100	9	60	< 48 h	18 h daily for 4 d	Spontaneous breathing and O₂ index < 6	Yes

Voggenreiter et al.,38 2005	40	Acute lung injury (duration ≥ 24 h) or ARDS^‡ (duration ≥ 8 h) with PEEP ≥ 5 cm H₂O	221	11.5	49	< 48 h	11 h daily for 7 d	Pao₂/Fio₂ ratio > 300 mm Hg for 48 h	Yes

Guérin et al.,16 2004	802	Hypoxemic acute respiratory failure (n = 413 with acute lung injury or ARDS^‡)	152	8	66	> 12–24 h	9 h daily for 4.1 d	Clinical improvement^¶	No

Beuret et al.,39 2002	53	Coma, intubation required (n = 7 with acute lung injury or ARDS^‡)	326 (238 in pts with acute lung injury or ARDS)	NR	NR	< 24 h	4 h daily for 6.0 d	Able to sit in chair	No

Watanabe et al.,40 2002	16	Pao₂/Fio₂ ratio < 200 mm Hg, PEEP > 5 cm H₂O 5 d after esophagectomy	166^**	NR	NR	Not prespecified	6 h daily for 4 d	Not applicable	No

Gattinoni et al.,15 2001	304	Acute lung injury or ARDS^‡ with PEEP ≥ 5 cm H₂O	127	10	73	Not prespecified	7 h daily for 4.7 d	None	No

Note: ARDS = acute respiratory distress syndrome, Fio₂ = fractional concentration of inspired oxygen, NR = not reported, Pao₂ = partial pressure of arterial oxygen, PEEP = positive end-expiratory pressure.
↵* Additional details about the study characteristics are available in Appendix 3 (www.cmaj.ca/lookup/suppl/doi:10.1503/cmaj.140081/-/DC1).
↵† Tidal volume < 8 mL/kg of predicted body weight.
↵‡ Defined according to the criteria of the American–European Consensus Conference.18
↵§ Average over first 2 d only; average number of days that prone positioning was used was not available.
↵¶ Defined by 1 major criterion (improvement in Pao₂/Fio₂ ratio ≥ 30% relative to value at randomization, with Fio₂ ≤ 60%) and at least 1 minor criterion (PEEP ≤ 8 cm H₂O, no sepsis, cause of acute respiratory failure under control [stable or signs of improvement on chest radiograph, and < 3 organ dysfunctions, including lung dysfunction]).
↵** Prone group only (baseline ratio in supine group not reported).