Conservative Oxygen Targets in Mechanically Ventilated Patients (OXY-BREATHES): A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

Abstract

To evaluate the efficacy and safety of conservative (oxygen saturation [Spo2] 88-94% or Pao2 < 80 mm Hg) vs. liberal oxygen targets (Spo2 ≥ 94% or Pao2 ≥ 90 mm Hg) in mechanically ventilated critically ill adults. PubMed, Cochrane CENTRAL, Embase, and ClinicalTrials.gov. We conducted the OXY-BREATHES, a systematic review and meta-analysis of randomized controlled trials (RCTs) comparing conservative vs. liberal oxygen targets in mechanically ventilated ICU patients. Primary outcomes were 90-day mortality and ICU length of stay. Secondary outcomes included ventilator- and vasopressor-free days, renal replacement therapy, nosocomial pneumonia, and cardiac or cerebral ischemic events. Subgroup analyses included patients with sepsis/septic shock and post-cardiac arrest. Data were collected according to study selection criteria. Certainty of evidence was appraised with Grading of Recommendations, Assessment, Development, and Evaluation, and risk of bias with the Cochrane tool. Data were analyzed using a random-effects model. Nine RCTs enrolling 20,447 patients were included. Conservative and liberal targets showed no substantial differences in 90-day (risk ratio [RR], 1.01; 95% CI, 0.94-1.09) or ICU length of stay (mean difference [MD], -0.17; 95% CI, -0.41 to 0.06). Secondary outcomes, including organ support-free days and the incidence of adverse events, were comparable between groups. In subgroup analyses, conservative targets yielded more vasopressor-free days in septic patients (MD, 2.0; p = 0.008) and a potential survival benefit in post-cardiac arrest patients (RR, 0.89; p = 0.05). Certainty of evidence was rated moderate for 90-day mortality, ICU length of stay, vasopressor-free days, and ventilator-free days; low for renal replacement therapy and nosocomial pneumonia; and very low for cerebral and cardiac ischemia due to imprecision and open-label trial designs. Conservative oxygenation is comparable to liberal oxygen targets in mechanically ventilated critically ill patients, with possible advantages in sepsis and post-cardiac arrest. Future condition-specific RCTs are warranted to define optimal ICU oxygen strategies.