Oxygen therapy for acute myocardial infarction: A systematic review and meta-analysis.

BACKGROUND Potential benefits or risks of oxygen inhalation for patients with acute myocardial infarction are not fully understood. OBJECTIVE We performed this study to systematically assess the effectiveness and safety of oxygen therapy for patients with acute myocardial infarction. DESIGN A systematic review and meta-analysis. DATA SOURCES We searched randomized controlled trials systematically in PubMed, EMBASE, Web of Science and Cochrane Library up to June 2016. REVIEW METHODS Randomized controlled trials that estimated the effectiveness and safety of oxygen therapy for patients with acute myocardial infarction were identified by two independent reviewers. The primary outcomes were short-term mortality and recurrent rate of myocardial infarction, and the secondary outcomes were arrhythmia incidence and pain incidence. Relative risks (RRs) and 95% confidence intervals (CIs) were used to measure the pooled data. RESULTS A total of five randomized controlled trials were in accordance with inclusion criteria and were included in this meta-analysis. Compared with no oxygen group, the oxygen group did not significantly reduce short-term death (RR: 1.08, 95%CI: 0.31-3.74), and there was moderate heterogeneity (I2=50.8%, P<0.107) among studies. We found a significant increase in the rate of recurrent myocardial infarction (RR: 6.73, 95%CI: 1.80-25.17, I2=0.0%, P=0.598) in the oxygen group. The oxygen group did not have a significant reduction in arrhythmia (RR: 1.12, 95%CI: 0.91-1.36; I2=46.2%, P<0.156) or pain (RR: 0.97, 95%CI: 0.91-1.04; I2=7.2%, P=0.340). CONCLUSIONS Oxygen inhalation did not benefit patients with acute myocardial infarction with normal oxygen saturation. It may increase the rate of recurrent myocardial infarction. High quality trials with larger sample sizes are required.