Cochrane Clinical Answers - Fulltext - In people with confirmed or suspected acute myocardial infarction, what are the effects of oxygen therapy?

Question:In people with confirmed or suspected acute myocardial infarction, what are the effects of oxygen therapy?

Clinical Answer:

In people with confirmed or suspected acute myocardial infarction (AMI), very low- to low-quality evidence fails to demonstrate any clinical benefit in routine use of oxygen compared with room air when evaluating mortality, opiate use, or complications of AMI (cardiac failure, recurrent MI or major bleeding) at four weeks’ follow-up.

Full outcome data is detailed below:

1.Oxygen versus air

  • Population, Intervention, Comparator

    Population:

    Adults (75% men; mean age range 51 to 64 years) with confirmed or suspected acute myocardial infarction presenting within 12-24 hours after onset of symptoms

    Intervention:

    Oxygen administered by medium concentration (MC) or face mask at 4-8 L/min over 24 hours or via nasal cannula 3 - 6 L/min (FiO? 30 - 40%)

    Comparator:

    Air at normal pressure given at 6 L/min by MC or face mask over 24 hours

  • OUTCOME 1.1: Death in hospital for all participants (including those who did not have an AMI) at 4 weeks’ follow-up

    Quality of the evidence:

    The reviewers performed a GRADE assessment of the quality of evidence for this outcome at this time point and stated that the evidence was very low quality. See Summary of findings from Cochrane review

    Narrative result:

    Four RCTs with 1123participants found no statistically significant difference between groups but may have been underpowered to detect clinically meaningful differences. Most of the participants had confirmed AMI at treatment onset.

    Relative effect or mean difference:

    There was no statistically significant difference between groups (RR 0.99, 95% CI 0.50 to 1.95).

    Forest plot from Cochrane Review

    Absolute effect:

    28 per 1000 people (95% CI 14 to 55) with oxygen compared with 28 per 1000 people with air.

    Reference:
    Cabello JB, Burls A, Emparanza JI, Bayliss SE, Quinn T. Oxygen therapy for acute myocardial infarction. Cochrane Database of Systematic Reviews 2016, Issue 12. Art. No.: CD007160. DOI: 10.1002/14651858.CD007160.pub4. [Review search date: June 2016]
    • OUTCOME 1.2: Opiate use in hospital (as a proxy measure for pain) for all participants (including those who did not have an AMI) at 4 weeks’ follow-up

      Quality of the evidence:

      The reviewers performed a GRADE assessment of the quality of evidence for this outcome at this time point and stated that the evidence was low quality. See Summary of findings from Cochrane review

      Narrative result:

      Two RCTs with 250 participants found no statistically significant difference between groups. Most of the participants had confirmed AMI at treatment onset.

      Relative effect or mean difference:

      There was no statistically significant difference between groups (RR 0.97, 95% CI 0.78 to 1.20).

      Forest plot from Cochrane Review

      Absolute effect:

      566 per 1000 people (95% CI 455 to 700) with oxygen compared with 583 per 1000 people with air.

      Reference:
      Cabello JB, Burls A, Emparanza JI, Bayliss SE, Quinn T. Oxygen therapy for acute myocardial infarction. Cochrane Database of Systematic Reviews 2016, Issue 12. Art. No.: CD007160. DOI: 10.1002/14651858.CD007160.pub4. [Review search date: June 2016]
      • OUTCOME 1.3: Cardiac failure at 4 weeks’ follow-up

        Risk of bias of studies:

        The reviewers did not perform a GRADE assessment of the quality of evidence. The studies reported report adequate allocation concealment and random sequence generation, did not report adequate blinding of participants/carers/outcome assessors and had unclear numbers of withdrawals.

        Narrative result:

        Two RCTs with 775 participants found no statistically significant difference between groups.

        Relative effect or mean difference:

        There was no statistically significant difference between groups (RR 0.88, 95% CI 0.50 to 1.55).

        Forest plot from Cochrane Review

        Absolute effect:

        55 per 1000 people (95% CI 31 to 97) with oxygen compared with 62 per 1000 people with air.

        Reference:
        Cabello JB, Burls A, Emparanza JI, Bayliss SE, Quinn T. Oxygen therapy for acute myocardial infarction. Cochrane Database of Systematic Reviews 2016, Issue 12. Art. No.: CD007160. DOI: 10.1002/14651858.CD007160.pub4. [Review search date: June 2016]
        • OUTCOME 1.4: Recurrent myocardial infarction (or ischemia) at 4 weeks’ follow-up

          Quality of the evidence:

          The reviewers performed a GRADE assessment of the quality of evidence for this outcome at this time point and stated that the evidence was low quality. See Summary of findings from Cochrane review

          Narrative result:

          Two RCTs with 578 participants found no statistically significant difference between groups.

          Relative effect or mean difference:

          There was no statistically significant difference between groups (RR 1.67, 95% CI 0.94 to 2.99).

          Forest plot from Cochrane Review

          Absolute effect:

          87 per 1000 people (95% CI 50 to 152) with oxygen compared with 64 per 1000 people with air.

          Reference:
          Cabello JB, Burls A, Emparanza JI, Bayliss SE, Quinn T. Oxygen therapy for acute myocardial infarction. Cochrane Database of Systematic Reviews 2016, Issue 12. Art. No.: CD007160. DOI: 10.1002/14651858.CD007160.pub4. [Review search date: June 2016]
          • OUTCOME 1.5: Major bleeding at 4 weeks’ follow-up

            Risk of bias of studies:

            The reviewers did not perform a GRADE assessment of the quality of evidence. The study reported report adequate allocation concealment and random sequence generation, did not report adequate blinding of participants/carers/outcome assessors and had unclear numbers of withdrawals.

            Narrative result:

            One RCT with 441 participants found no statistically significant difference between groups.

            Relative effect or mean difference:

            There was no statistically significant difference between groups (RR 1.53, 95% CI 0.56 to 4.24).

            Forest plot from Cochrane Review

            Absolute effect:

            41 per 1000 people (95% CI 15 to 114) with oxygen compared with 27 per 1000 people with air.

            Reference:
            Cabello JB, Burls A, Emparanza JI, Bayliss SE, Quinn T. Oxygen therapy for acute myocardial infarction. Cochrane Database of Systematic Reviews 2016, Issue 12. Art. No.: CD007160. DOI: 10.1002/14651858.CD007160.pub4. [Review search date: June 2016]
            • OUTCOME 1.6: Adverse events

              Narrative result:

              The reviewers did not assess this outcome.

              Reference:
              Cabello JB, Burls A, Emparanza JI, Bayliss SE, Quinn T. Oxygen therapy for acute myocardial infarction. Cochrane Database of Systematic Reviews 2016, Issue 12. Art. No.: CD007160. DOI: 10.1002/14651858.CD007160.pub4. [Review search date: June 2016]

              Additional Information:

              DOI

              10.1002/cca.1547

              Publication Dates

              1. Published Online: 31 JAN 2017

              CCA derived from

              Cabello JB, Burls A, Emparanza JI, Bayliss SE, Quinn T. Oxygen therapy for acute myocardial infarction. Cochrane Database of Systematic Reviews 2016, Issue 12. Art. No.: CD007160. DOI: 10.1002/14651858.CD007160.pub4. [Review search date: June 2016]

              How to Cite

              In people with confirmed or suspected acute myocardial infarction, what are the effects of oxygen therapy? Dane Gruenebaum (DO, MBA) (on behalf of Cochrane Clinical Answers Editors). Cochrane Clinical Answers 2017. DOI: 10.1002/cca.1547.

              Further Information

              • CCA Associate editor: Dane Gruenebaum (DO, MBA), Clinical Instructor, Michigan State University, East Lansing, MI, USA.
              • CCA Editor: Karen Pettersen. Correspondence to kpettersen@wiley.com.