Impact of Conservative Versus Conventional Oxygenation on Outcomes of Patients in Intensive Care Units: A Systematic Review and Meta-analysis

Background: There is mixed evidence in the superiority of conservative versus conventional approach to oxygen therapy among patients admitted into the intensive care unit (ICU). The purpose of this study was to determine if conservative versus conventional oxygenation results in a statistically significant difference in outcomes in ICU patients. Methods: A systematic review was registered with the International Prospective Register of Systematic Reviews (PROSPERO) and performed using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Inclusion criteria consisted of Level I-IV investigations of conservative versus conventional oxygenation among ICU patients. ICU mortality, 28-day mortality, in-hospital mortality, ICU length-of-stay, hospital length-ofstay, rate of new infections, and rate of new non-respiratory organ failure were compared using two-sample Z-tests using p-value less than 0.05. Results: Three thousand four hundred thirty-three articles were screened. Four articles were included in the analysis. Three hundred seventy-two patients under the conservative oxygenation arm (Minimum target SpO2: 88-94%) and 370 patients under the conventional oxygenation arm (Minimum target SpO2: 96-97%) were analyzed. ICU mortality (16.7 +/- 9.5% vs. 22.7 +/- 6.0%; P<0.01), 28-day mortality (34.6 +/- 26.4% vs. 41.6 +/- 14.6%; P=0.02), and in-hospital mortality (30.2 +/- 22.5% vs. 37.7 +/- 14.2%; P<0.01) were all significantly lower in the conservative oxygenation arm versus the conventional oxygenation arm, respectively. Rate of new non-respiratory organ failure was also significantly lower in the conservative oxygenation arm (20.0 +/- 8.5% vs. 29.7 +/- 11.7%; P<0.01). Conclusion: The authors conclude that conservative oxygenation therapy could result in significantly lower rates of ICU mortality, 28-day mortality, in-hospital mortality, and newonset non-respiratory organ failure. Further randomized controlled studies that show clinical outcome improvement in multiple parameters may be worthwhile to assess the true efficacy of this practice.