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Original research article
Effects of supplemental oxygen therapy in patients with suspected acute myocardial infarction: a meta-analysis of randomised clinical trials
  1. Nariman Sepehrvand1,
  2. Stefan K James2,
  3. Dion Stub3,
  4. Ardavan Khoshnood4,5,
  5. Justin A Ezekowitz1,6,
  6. Robin Hofmann7
  1. 1 Canadian VIGOUR Centre and Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
  2. 2 Department of Medical Sciences and Uppsala Clinical Research Center, Uppsala University, Uppsala, Sweden
  3. 3 Monash University, The Alfred Hospital and Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia
  4. 4 Department of Clinical Sciences, Skåne University Hospital, Lund University, Lund, Sweden
  5. 5 Department of Emergency and Internal Medicine, Skåne University Hospital, Lund University, Lund, Sweden
  6. 6 Mazankowski Alberta Heart Institute, Edmonton, Alberta, Canada
  7. 7 Division of Cardiology, Department of Clinical Science and Education, Karolinska Institutet, Stockholm, Sweden
  1. Correspondence to Dr Justin A Ezekowitz, The Canadian VIGOUR Centre, LiKa Shing Center for Health Innovation, Edmonton, AlbertaT6G 2E1, Canada; jae2{at}


Background Although oxygen therapy has been used for over a century in the management of patients with suspected acute myocardial infarction (AMI), recent studies have raised concerns around the efficacy and safety of supplemental oxygen in normoxaemic patients.

Objective To synthesise the evidence from randomised controlled trials (RCTs) that investigated the effects of supplemental oxygen therapy compared with room air in patients with suspected or confirmed AMI.

Methods For this aggregate data meta-analysis, multiple databases were searched from inception to 30 September 2017. RCTs with any length of follow-up and any outcome measure were included if they studied the use of supplemental O2 therapy administered by any device at normal pressure compared with room air. Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, an investigator assessed all the included studies and extracted the data. Outcomes of interests included mortality, troponin levels, infarct size, pain and hypoxaemia.

Results Eight RCTs with a total of 7998 participants (3982 and 4002 patients in O2 and air groups, respectively) were identified and pooled. In-hospital and 30-day death occurred in 135 and 149 patients, respectively. Oxygen therapy did not reduce the risk of in-hospital (OR, 1.11 (95% CI 0.69 to 1.77)) or 30-day mortality (OR, 1.09 (95% CI 0.80 to 1.50)) in patients with suspected AMI, and the results remained similar in the subgroup of patients with confirmed AMI. The infarct size (based on cardiac MRI) in a subgroup of patients was not different between groups with and without O2 therapy. O2 therapy reduced the risk of hypoxaemia (OR, 0.29 (95% CI 0.17 to 0.47)).

Conclusion Although supplemental O2 therapy is commonly used, it was not associated with important clinical benefits. These findings from eight RCTs support departing from the usual practice of administering oxygen in normoxaemic patients.

  • acute myocardial infarction
  • meta-analysis

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  • NS and SKJ contributed equally.

  • Contributors All authors contributed to the design, analysis and preparation of the manuscript. NS and SKJ contributed equally as first authors.

  • Funding JAE and NS received funding from Heart and Stroke Foundation of Canada and Alberta Innovates, Health Solutions. DS is supported by National Heart Foundation of Australia and Viertel fellowships.

  • Competing interests None declared.

  • Patient consent Not required.

  • Provenance and peer review Not commissioned; externally peer reviewed.