Abstract

Objective: To undertake a systematic review and meta-analysis of randomised placebo-controlled trials of oxygen therapy in myocardial infarction (MI).

Design: A systematic search of Medline, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, EMBASE and CINHAL was undertaken using the key words “oxygen” and “myocardial infarction” to identify randomised placebo-controlled trials of oxygen therapy in MI.

Main outcome measures: The primary clinical outcome was mortality; secondary outcomes were infarct size, occurrence of ventricular arrhythmias and opiate use.

Results: Two of 51 potentially relevant studies met the criteria. The one study with substantive clinical outcome data reported that high flow oxygen was associated with a non-significant increased risk of death (risk ratio 2.9, 95% CI 0.8 to 10.3, P=0.08), and a greater serum aspartate aminotransferase level (difference 19.2 IU/ml, 95% CI 0 to 38.4, P=0.05) in uncomplicated MI. Neither of the identified studies had adequate statistical power to detect clinically important differences in other clinical outcome measures.

Conclusion: There is little evidence by which to determine the efficacy and safety of high flow oxygen therapy in MI. The evidence that does exist suggests that the routine use of high flow oxygen in uncomplicated MI may result in a greater infarct size and possibly increase the risk of mortality.