Home›Rheumatology› Systematic review and meta-analysis of RCTs shows no mortality benefit for conservative oxygen therapy in mechanically ventilated adults
Systematic review and meta-analysis of RCTs shows no mortality benefit for conservative oxygen therapy in mechanically ventilated adultsDoes Oxygen Level Matter for Ventilated Patients? New Data Says No
Frontiers in MedicinePublished April 24, 2026DOI ↗Editorial oversight: Dr. Amelia Tan, PhD · Internal Medicine & Chronic Disease
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Key Takeaway
Consider that conservative oxygen therapy offers no mortality benefit over liberal therapy in mechanically ventilated adults overall.
This systematic review and meta-analysis of randomized controlled trials assessed the impact of conservative oxygen therapy (COT) compared with liberal oxygen therapy (LOT) on outcomes in adult mechanically ventilated patients. The analysis pooled data from a total sample size of 20,786 patients across multiple trials. The primary outcome was overall mortality, with secondary outcomes including ICU mortality, 90-day mortality, ICU length of stay, hospital length of stay, and mechanical ventilation hours.
The results indicated no significant difference in overall mortality between the two strategies, with a relative risk of 1.02 (95% CI 0.95–1.10; Z = 0.54, p = 0.59). Similarly, no significant differences were observed for ICU mortality (RR 1.07; 95% CI 0.89–1.33; Z = 0.71, p = 0.48), 90-day mortality (RR 1.04; 95% CI 0.96–1.12; Z = 0.92, p = 0.36), ICU length of stay (MD −0.02; 95% CI −0.05–0.01, Z = −1.42, p = 0.15), hospital length of stay (MD 0.00; 95% CI −0.06–0.07, Z = 0.14, p = 0.89), or mechanical ventilation hours (MD −0.05; 95% CI −0.92–0.81, Z = −0.12, p = 0.91). Adverse events were not reported.
The authors acknowledge that the absence of overall benefit in this broad population does not preclude the possibility that selected subgroups or different target ranges could prove advantageous. However, the source does not provide specific data to support benefit in these subgroups. Consequently, clinicians should interpret these findings with caution regarding the universal application of COT versus LOT strategies.
Why Oxygen Levels Spark Debate
Think of oxygen like fuel for a car. You need enough to run. But too much can cause problems. The body uses oxygen to keep organs working. Too little can starve them. Too much might create stress.
Researchers combined data from eleven different studies. They looked at over twenty thousand adults. All patients were on breathing machines. They compared death rates and hospital stays. The study covered patients from 2014 to 2025.
The Surprising Shift in Care
The results were very clear. Patients did not die more often with either method. The time spent in the hospital was the same. The time on the machine was also the same. High oxygen did not save more lives. Low oxygen did not save more lives.
But there is a catch.
Experts say this does not mean oxygen does not matter. It means the standard range works for most people. Some patients might still need special care. Doctors must look at each person closely.
If you have a family member in the ICU, this is good news. You do not need to worry about the exact number. The medical team is doing the right thing. They will adjust settings based on the patient's needs.
This study looked at a broad group of people. It did not focus on specific diseases. Some patients might still benefit from one method. We need more work to find those groups.
Doctors will keep watching the data. They want to know if specific groups need different care. Research takes time to change rules. For now, both methods are safe choices.
Study Details
Study typeMeta analysis
EvidenceLevel 1
PublishedApr 2026
View Original Abstract ↓
BackgroundCurrently, clinicians lack sufficient evidence to determine which oxygen therapy approach yields better outcomes in mechanically ventilated (MV) patients, whether conservative oxygen therapy (COT) or liberal oxygen therapy (LOT).MethodsThis study systematically searched for randomized controlled trials (RCTs) in PubMed, Embase, Web of Science, and Cochrane Library from the inception of each database to 1 September 2025. The outcome measures in MV patients included overall mortality, intensive care unit (ICU) mortality, 90-day mortality, ICU length of stay (LOS), hospital LOS, and MV hours.ResultsThis meta-analysis included 11 RCTs published between 2014 and 2025, involving a total of 20,786 adult MV patients. There was no significant difference in overall mortality between the COT and LOT groups (RR 1.02, 95% CI 0.95–1.10; Z = 0.54, p = 0.59) nor in ICU mortality (RR 1.07, 95% CI 0.89–1.33; Z = 0.71, p = 0.48) and 90-day mortality (RR 1.04, 95% CI 0.96–1.12; Z = 0.92, p = 0.36). There was no significant difference in ICU LOS between COT and LOT (MD −0.02, 95% CI −0.05–0.01, Z = −1.42, p = 0.15), or in hospital LOS (MD 0.00, 95% CI −0.06–0.07, Z = 0.14, p = 0.89), and MV hours (MD −0.05, 95% CI −0.92–0.81, Z = −0.12, p = 0.91).ConclusionIn this meta-analysis of MV patients, COT was not associated with a reduction in overall mortality, ICU mortality, 90-day mortality, ICU LOS, hospital LOS, and MV hours when compared with LOT. The absence of overall benefit from COT in this broad population does not preclude the possibility that selected subgroups or different target ranges could prove advantageous.Systematic review registrationhttps://www.crd.york.ac.uk/PROSPERO/view/CRD420251137389.
