The effect of conservative oxygen therapy in reducing mortality in critical care patients: A systematic review and meta analysis

Background: Conservative oxygen therapy can avoid both the hypoxemia and hyperoxemia, but the effect of it on the prognosis of patients admitted to intensive care unit （ICU） remains controversial.Methods The Pubmed, Embase, Medline, Cochrane Central Register of Controlled Trials (CENTRAL) as well as the Information Sciences Institute (ISI) Web of Science were searched for all the controlled studies comparing conservative oxygen therapy and conventional oxygen therapy in adult patients admitted to ICU. The primary outcome was the mortality and the secondary outcomes were length of ICU stay (ICU LOS), length of hospital stay(hospital LOS), length of mechanical ventilation(MV) hours, new organ failure during ICU stay, new infection during ICU stay,.Results Six trials with a total of 2250 patients were pooled in our final studies. No statistical heterogeneity was found in all the analysis. Compared with conventional oxygen therapy, conservative oxygen therapy could not reduce overall mortality (Z=0.96, P=0.34), ICU LOS(Z=0.29, P=0.77)，hospital LOS(Z=1.98, P=0.05) and new infection during ICU stay (Z=0.94, P=0.35). However，conservative oxygen therapy was associated with lower MV time(Z=5.03, P<0.001) and new organ failure during ICU stay(Z=2.05, P=0.04).Conclusions Conservative oxygen therapy could not reduce the mortality but did lower the MV time and new organ failure in critically ill patients.