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, β 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.

Three part question

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

Search strategy

Medline 1966-10/03 using the OVID interface. [exp myocardial infarction OR myocardial infarct$.mp OR MI.mp OR heart attack.mp OR exp Coronary Thrombosis OR acute coronary syndrome.mp] AND [exp oxygen OR oxygen.mp OR O2.mp OR exp oxygen inhalation therapy] AND [exp Mortality OR exp Hospital Mortality OR mortality.mp OR exp Death OR death.mp] LIMIT to human AND English.

Search outcome

Altogether 290 papers were identified, only one of which was relevant to the question (table 1).

Comment(s)

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.