Table 1.

Description of included trials.

Study	Patient population	Initial mode of oxygen delivery	Country/region	Interventions			Participants			Baseline oxygenation a
				Liberal	Conservative	Duration	Sample size	Age a	Male (%)	Liberal	Conservative
Gelissen et al. 17	SIRS	MV, NC, mask or HFNO	Netherlands	PaO2 14–18 kPa	PaO2 8–12 kPa	Up to 14 days (while in ICU)	400	68	65	PaO2 12.3 kPa FIO2 0.46	PaO2 11.6 kPa FIO2 0.45
Martin et al. 18	MV for respiratory failure	MV only	UK	SpO2 ⩾ 96% b	SpO2 88%–92%	Until extubation, discharge or death	34	66	65	SpO2 97% PaO2 11.7 kPa FIO2 0.45	SpO2 94% PaO2 11.0 kPa FIO2 0.40
Schjørring et al. 25	Receiving supplemental O2 in ICU for respiratory failure	MV, NIV, open system	Europe	PaO2 12 kPa	PaO2 8 kPa	Up to 90 days (while in ICU)	2888	70	64	SaO2 95% PaO2 10.3 kPa FIO2 0.70	SaO2 94% PaO2 10.3 kPa FIO2 0.70
Barrot et al. 19	Mechanical ventilation for ARDS	MV only	France	PaO2 12–14 kPa SpO2 ⩾ 96%	PaO27.3–9.3 kPa SpO2 88%–92%	Up to 7 days (while intubated)	201	63 c	64	PaO2 12.3 kPa c FIO2 0.80 c	PaO2 12.0 kPa c FIO2 0.80 c
Mackle et al. 20	Mechanical ventilation	MV only	Australia & New Zealand	SpO2 ⩾ 91% FIO2 ⩾ 0.3	SpO2 91%–96%	Up to 28 days (while in ICU)	965	58 c	63	SpO2 96.7% c PaO2 14.9 kPa	SpO2 97.1% c PaO2 14.7 kPa
Yang et al. 24	Admissions with expected ICU stay ⩾72 h	MV and other modalities	China	SpO2 ⩾ 96%, FIO2 ⩾ 0.3	SpO2 90%–95%	Not reported	224	60 versus 56 d	67	Not reported	Not reported
Asfar et al. 21	Mechanical ventilation with septic shock	MV only	France	FIO2 1.0 e	SaO2 88%–95% e	24 h	434	68	64	SaO2 99% PaO2 16.3 kPa	SaO2 97% PaO2 16.9 kPa
Girardis et al. 22	Admissions with expected ICU stay ⩾72 h	MV and other modalities	Italy	SpO2 97%–100%, PaO2⩽ 20 kPa, FIO2 ⩾ 0.4	SpO2 94%–98% or PaO2 9.3–13.3 kPa	Not reported	478	65 versus 63d,f	57 f	Not reported	Not reported
Panwar et al. 23	Mechanical ventilation	MV only	Australia, New Zealand, France	SpO2 ⩾ 96%	SpO2 88%–92%	While receiving mechanical ventilation	103	62 c	63	SpO2 96% c PaO2 10.9 kPa FIO2 0.44 c	SpO2 95% c PaO2 10.8 kPa FIO2 0.44 c

SIRS: systemic inflammatory response syndrome.

^aMedian unless indicated.

^bChanged to usual care during the study.

^cMean.

^dLiberal versus conservative.

^e2 × 2 factorial design, also evaluated hypertonic versus isotonic saline.

^fOnly reported for modified ITT population (length of stay at least 72 h and at least one arterial blood gas per day).