FPIN's Clinical Inquiries

Supplemental Oxygen Therapy for Nonhypoxemic Patients with Acute Coronary Syndrome


Am Fam Physician. 2020 Jun 1;101(11):687-688.

Clinical Question

What are the risks and benefits of supplemental oxygen therapy in nonhypoxemic patients being treated for acute coronary syndrome?

Evidence-Based Answer

No conclusive evidence demonstrates that routine use of supplemental oxygen therapy is associated with clinical benefit or harm in nonhypoxemic patients with acute myocardial infarction (MI). (Strength of Recommendation [SOR]: A, based on systematic reviews and meta-analyses of randomized controlled trials [RCTs].) Supplemental oxygen therapy in patients with normal oxygen levels does not reduce pain, cardiac enzyme levels, infarct size, or the risk of in-hospital or 30-day mortality, but it does not worsen any of these outcomes. (SOR: A, based on systematic reviews and meta-analyses of RCTs.)

Evidence Summary

A 2016 Cochrane review of five RCTs (N = 1,173) compared the effects of supplemental oxygen with room air in adults presenting with acute MI (suspected or proven ST segment–elevation MI [STEMI] or non-STEMI) within 24 hours of symptom onset.1 All trials compared supplemental oxygen administered via mask or nasal cannula at rates of 4 to 8 L per minute with room air; follow-up periods ranged from four weeks to six months. Mortality was the primary outcome in all studies, but three also measured patient-reported pain or opiate use (as a proxy for pain) and biochemical markers (e.g., creatine kinase, troponin); two assessed risk of recurrent MI or ischemia. Pooled results from the trials showed no evidence of mortality benefit from the routine use of supplemental oxygen therapy in patients presenting with acute MI. An intention-to-treat analysis found that the relative risk (RR) of all-cause mortality was 0.99 (95% CI, 0.50 to 1.95); the RR increased to 1.02 (95% CI, 0.52 to 1.98) when only patients with confirmed MI were included. The included trials (n = 250) showed no improvement in pain with supplemental oxygen therapy (pooled RR = 0.97; 95% CI, 0.78 to 1.20). Analysis of two trials assessing the

Address correspondence to Lawrence M. Gibbs, MD, MSEd, at lawrencegibbs@mhd.com. Reprints are not available from the authors.

Author disclosure: No relevant financial affiliations.


show all references

1. Cabello JB, Burls A, Emparanza JI, et al. Oxygen therapy for acute myocardial infarction. Cochrane Database Syst Rev. 2016;(12):CD007160....

2. Sepehrvand N, James SK, Stub D, et al. Effects of supplemental oxygen therapy in patients with suspected acute myocardial infarction: a meta-analysis of randomised clinical trials. Heart. 2018;104(20):1691–1698.

3. Hofmann R, James SK, Jernberg T, et al.; DETO2X-SWEDEHEART Investigators. Oxygen therapy in suspected acute myocardial infarction. N Engl J Med. 2017;377(13):1240–1249.

4. O'Gara PT, Kushner FG, Ascheim DD, et al. 2013 ACCF/AHA guideline for the management of ST-elevation myocardial infarction. J Am Coll Cardiol. 2013;61(4):e78–e140.

5. Amsterdam EA, Wenger NK, Brindis RG, et al. 2014 AHA/ACC guideline for the management of patients with non-ST-elevation acute coronary syndromes [published correction apears in Circulation. 2014;130(25):e433–e434]. Circulation. 2014;130(25):e344–e426.

6. Ibanez B, James S, Agewall S, et al. 2017 ESC guidelines for the management of acute myocardial infarction in patients presenting with ST-segment elevation. Eur Heart J. 2018;39(2):119–177.

Clinical Inquiries provides answers to questions submitted by practicing family physicians to the Family Physicians Inquiries Network (FPIN). Members of the network select questions based on their relevance to family medicine. Answers are drawn from an approved set of evidence-based resources and undergo peer review. The strength of recommendations and the level of evidence for individual studies are rated using criteria developed by the Evidence-Based Medicine Working Group (https://www.cebm.net).

The complete database of evidence-based questions and answers is copyrighted by FPIN. If interested in submitting questions or writing answers for this series, go to https://www.fpin.org or email: questions@fpin.org.

This series is coordinated by John E. Delzell Jr., MD, MSPH, associate medical editor.

A collection of FPIN's Clinical Inquiries published in AFP is available at https://www.aafp.org/afp/fpin.



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