Table 2.

Summary of outcomes and Grading of Recommendations Assessment, Development, and Evaluation Evidence assessment

Outcomes	No. of Studies	Total No. Included in Analysis	Evidence Assessment (GRADE)	RR (95% CI)	P Value
Primary outcome
In-hospital mortality	10*	1,248	Mod	1.02 (0.79 to 1.33)	0.87
Secondary outcomes
LOS ICU	6†	162	Low	8.65 (−9.72 to 27.01)	0.36
Sensitivity analysis
In-hospital mortality RCT, quasi-RCT	6	713	Mod-High	0.80 (0.61 to 1.04)	0.09
In-hospital mortality RCT, quasi-RCT VV ECLS	3	504	Mod-High	0.64 (0.51 to 0.79)	<0.0001
In-hospital mortality RCT, quasi-RCT REVA match Pham‡	6	621	Mod-High	0.90 (0.69 to 1.16)	0.40
In-hospital mortality RCT, quasi-RCT lung-protective ventilation‡	4	583	Mod-High	0.65 (0.53 to 0.80)	<0.0001
Subgroup analysis, in-hospital mortality
H1N1	3	364	Mod-High	0.62 (0.45 to 0.84)	0.002
Lung-protective ventilation	6	773	Mod-High	0.82 (0.57 to 1.18)	0.29
>50% ARDS due to pneumonia	8	1,069	Mod	0.91 (0.72 to 1.14)	0.40
Age < 40 yr	5	737	Mod	1.08 (0.64 to 1.82)	0.77
ECLS within 1st wk	6	773	Mod	0.82 (0.57 to 1.18)	0.29
Very severe ARDS (average PF < 50)	2	168	Mod	0.63 (0.31 to 1.30)	0.21
VV ECMO	7	1,061	Mod	1.03 (0.98 to 1.57)	0.87
Adverse events
Adverse events: bleeding	5	429	Low-Mod	11.44 (3.11 to 42.06)	0.0002
Adverse events: barotrauma	2	162	Mod	1.46 (1.21 to 1.76)	< 0.0001
Adverse events: sepsis	3	333	Low-Mod	1.63 (0.82 to 3.26)	0.16

Definition of abbreviations: ARDS = acute respiratory distress syndrome; CI = confidence interval; ECLS = extracorporeal life support; GRADE = Grading of Recommendations Assessment, Development, and Evaluation; ICU = intensive care unit; LOS = length of stay; PF = Pa_O2/Fi_O2; Mod = moderate; RCT = randomized controlled trial; REVA = Réseau Européen de recherche en Ventilation Artificielle; RR = risk ratio; VV = venovenous.

^*Peek included composite endpoint of in-hospital and <6-month mortality.

^†Only two studies had complete data including SDs to accurately combine in metaanalysis.

^‡See online supplement.