Study designs of evaluations included in the review
Controlled trials were eligible for the review. Both randomised controlled trials (RCTs) and non-randomised controlled clinical trials (CCTs) were included.
Specific interventions included in the review
Studies of oxygen delivered by any delivery device (nasal cannula, mask or tent) or at any flow rate were eligible for the review. Hyperbaric oxygen was excluded. Most of the included studies used variable flow rates and lengths of treatment.
Participants included in the review
Studies of patients with acute coronary syndrome were eligible for the review. Most of the included studies were of patients with acute myocardial infarction; others were of patients with coronary artery disease or severe angina pectoris. Eighty per cent of the included patients were men.
Outcomes assessed in the review
Studies that reported some measure of myocardial ischaemia were eligible for the review. Four measures were used in the included studies: haemodynamic parameters, metabolic markers, electrocardiogram markers and changes in clinical symptoms.
How were decisions on the relevance of primary studies made?
The single author determined the relevance of studies for the review.