Best Evidence Topics
  • Send this BET as an Email
  • Make a Comment on this BET

Oxygen in acute uncomplicated myocardial infarction

Three Part Question

In [patients with acute uncomplicated myocardial infarction] does [oxygen therapy] lead to [reduced mortality]?

Clinical Scenario

A 60-year-old man presents to the Emergency Department with acute severe crushing chest pain. ECG shows changes consistent with acute myocardial infarction. You prescribe aspirin, thrombolysis, nitroglycerin, beta-blockers and high-flow oxygen. You know that oxygen therapy is traditionally held to be beneficial in this situation, but wonder if there is any evidence that it reduces mortality.

Search Strategy

Medline 1966-10/03 using the OVID interface.
[exp myocardial infarction OR myocardial infarct$.mp OR OR heart OR exp Coronary Thrombosis OR acute coronary] AND [exp oxygen OR OR OR exp oxygen inhalation therapy] AND [exp Mortality OR exp Hospital Mortality OR OR exp Death OR] LIMIT to human AND English.

Search Outcome

Altogether 290 papers were identified, only one of which was relevant to the question.

Relevant Paper(s)

Author, date and country Patient group Study type (level of evidence) Outcomes Key results Study Weaknesses
Rawles JM & Kenmure ACR,
157 patients with acute uncomplicated myocardial infarction Oxygen vs. compressed air via MC mask at 6l/min for 24 hoursPRCTIncidence of arrhythmiasMore sinus tachycardia in oxygen group (p<0.05); no other significant differencesNo power calculation No assessment of pain scores Effect of implementing intention to treat analysis not discussed
Number of patients given analgesics/number of doses given (diamorphine)No significant difference
Mortality9 vs 3 deaths (not significant)


The routine use of oxygen in myocardial infarction has been widely advocated for many years. However, the only study to investigate the efficacy of this approach was underpowered to show a difference in mortality.

Clinical Bottom Line

In patients with uncomplicated acute myocardial infarction there is no evidence that supplemental oxygen reduces mortality. However the there is no evidence of harm. Further research is required before changes in current practice should be recommended.


  1. Rawles JM, Kenmure ACF. Controlled trial of oxygen in uncomplicated myocardial infarction. BMJ 1976;1(6018):1121-1123.