Chu DK, et al. - The efficacy and safety of liberal vs conservative oxygen therapy were systematically reviewed in acutely ill adults. Researchers gained high-quality evidence indicating that liberal oxygen therapy increases mortality without improving other patient-important outcomes. Above saturation of peripheral oxygen range of 94–96%, supplemental oxygen might become unfavourable. The conservative administration of oxygen therapy was thus supported.

Methods

• Researchers searched for randomised controlled trials comparing liberal and conservative oxygen therapy in acutely ill adults (aged ≥18 years) via inquiring the Cochrane Central Register of Controlled Trials, MEDLINE, Embase, HealthSTAR, LILACS, PapersFirst, and the WHO International Clinical Trials Registry from inception to Oct 25, 2017, in the Improving Oxygen Therapy in Acute-illness (IOTA) systematic review and meta-analysis.
• They limited the studies to patients with chronic respiratory diseases or psychiatric disease; patients on extracorporeal life support, or patients treated with hyperbaric oxygen therapy or elective surgery were excluded.
• Studies were screened and summary estimates were extracted independently and in duplicate.
• Individual patient-level data from survival curves was also extracted.
• Mortality (in-hospital, at 30 days, and at longest follow-up) and morbidity (disability at longest follow-up, risk of hospital-acquired pneumonia, any hospital-acquired infection, and length of hospital stay) assessed by random-effects meta-analyses were the main outcomes.
• Quality of evidence was assessed using the grading of recommendations assessment, development, and evaluation approach. 

Results

• Researchers identified 25 randomised controlled trials enrolling 16,037 patients with sepsis, critical illness, stroke, trauma, myocardial infarction, or cardiac arrest, and patients who had emergency surgery.
• They noted that in comparison to a conservative oxygen strategy, a liberal oxygen strategy (median baseline saturation of peripheral oxygen [SpO₂] across trials, 96% [range 94–99%, IQR 96–98]) increased mortality in-hospital (relative risk [RR] 1·21, 95% CI 1·03–1·43, I²=0%, high quality), at 30 days (RR 1·14, 95% CI 1·01–1·29, I²=0%, high quality), and at longest follow-up (RR 1·10, 95% CI 1·00–1·20, I²=0%, high quality).
• The groups were similar in terms of morbidity outcomes.
• Findings were noted to be robust to trial sequential, subgroup, and sensitivity analyses.