Comparison 1. Recruitment manoeuvres versus no recruitment manoeuvres.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 28‐Day mortality	5	1450	Risk Ratio (M‐H, Fixed, 95% CI)	0.86 [0.74, 1.01]
1.1 Open lung ventilation including recruitment manoeuvres	4	1340	Risk Ratio (M‐H, Fixed, 95% CI)	0.88 [0.75, 1.04]
1.2 Recruitment manoeuvres	1	110	Risk Ratio (M‐H, Fixed, 95% CI)	0.67 [0.40, 1.11]
2 ICU mortality	5	1370	Risk Ratio (M‐H, Fixed, 95% CI)	0.85 [0.73, 0.99]
2.1 Open lung ventilation including recruitment manoeuvres	4	1260	Risk Ratio (M‐H, Fixed, 95% CI)	0.88 [0.75, 1.03]
2.2 Recruitment manoeuvres	1	110	Risk Ratio (M‐H, Fixed, 95% CI)	0.62 [0.39, 0.98]
3 In‐hospital mortality	4	1313	Risk Ratio (M‐H, Fixed, 95% CI)	0.88 [0.77, 1.01]
3.1 Open lung ventilation including recruitment manoeuvres	3	1203	Risk Ratio (M‐H, Fixed, 95% CI)	0.90 [0.78, 1.04]
3.2 Recruitment manoeuvres	1	110	Risk Ratio (M‐H, Fixed, 95% CI)	0.74 [0.50, 1.09]
4 Rate of barotrauma	7	1508	Risk Ratio (M‐H, Fixed, 95% CI)	1.09 [0.78, 1.51]
4.1 Open lung ventilation including recruitment manoeuvres	6	1398	Risk Ratio (M‐H, Fixed, 95% CI)	1.09 [0.78, 1.51]
4.2 Recruitment manoeuvres	1	110	Risk Ratio (M‐H, Fixed, 95% CI)	0.0 [0.0, 0.0]
5 Use of rescue therapies	3	1060	Risk Ratio (M‐H, Random, 95% CI)	0.64 [0.27, 1.51]
6 PaO2/FiO2 ratio at 24 to 48 hours	6	1270	Mean Difference (IV, Random, 95% CI)	‐39.10 [‐57.64, ‐20.56]
6.1 Open lung ventilation including recruitment manoeuvres	5	1160	Mean Difference (IV, Random, 95% CI)	‐44.76 [‐66.29, ‐23.22]
6.2 Recruitment manoeuvres	1	110	Mean Difference (IV, Random, 95% CI)	‐17.0 [‐37.19, 3.19]