Abstract
Background: Oxygen therapy remains integral to the management of patients in the Intensive Care Unit (ICU), yet there are no clear guidelines on the optimal method of oxygenation. While oxygen delivery may be enhanced by liberal oxygen supplementation, there are associated dangers, in addition to the potential benefits of avoiding hyperoxia through conservative strategies. The present study aims to examine the effectiveness and safety of liberal oxygen compared with conservative oxygenation in severely ill patients who can breathe spontaneously in the ICU, by conducting a systematic review and meta-analysis of randomized controlled trials on this topic.
Methods: A comprehensive literature review was executed across various databases, including PubMed, Scopus, Web of Science, and Cochrane, to identify relevant randomized controlled trials evaluating the efficacy of liberal oxygenation in critically ill patients in the ICU. In the subsequent phase, pertinent information was meticulously extracted, followed by the extraction of outcomes of interest. A meta-analysis was conducted using RevMan software, which employed a random-effects model.
Results: This systematic review and meta-analysis included 18 clinical trials evaluating the effects of liberal versus conservative oxygenation in critically ill patients. Liberal oxygenation slightly increased FiO₂ (MD = 0.10, 95% CI [0.07, 0.13], p < 0.01) and PaO₂ (MD = 4.08, 95% CI [1.51, 6.66], p < 0.01) but did not significantly improve ICU mortality (RR = 0.96, 95% CI [0.88, 1.06], p = 0.44), 4-week mortality, or 90-day mortality. Secondary outcomes, including duration of ICU stay and complications such as mesenteric ischemia and pneumonia, showed no significant differences between strategies. The findings suggest minimal clinical benefits of liberal oxygenation, emphasizing the importance of individualized approaches.
Conclusion: This meta-analysis established that liberal oxygenation moderately elevated FiO₂ and PaO₂ without affecting mortality rate or causing any significant change in the secondary outcomes in critically ill patients. Both strategies had comparable effects on the complications and recovery parameters in the ICU, which calls for a more personalized strategy for oxygen therapy. These findings suggest that liberal oxygenation and conservative oxygenation are not superior to each other in all aspects, and thus, strategies should be tailored to address a patient’s needs and potential risks.

Key words: Conservative oxygenation, Critically ill patients, Intensive Care Unit (ICU), Liberal oxygenation, Oxygen therapy.