Supplemental oxygen in STEMI without hypoxia – AVOID

Supplemental oxygen in STEMI without hypoxia – AVOID

It was routine practice to give supplemental oxygen to those presenting to emergency department with ST elevation myocardial infarction. Two trials – AVOID [1] and DETO2X-AMI [2] have critically appraised the value of supplemental oxygen in STEMI.

AVOID study showed that in STEMI patients without hypoxia, supplemental oxygen can increase early myocardial injury which was demonstrated by a higher value of creatine phosphokinase. Larger myocardial infarct size as assessed by cardiac magnetic resonance imaging was noted at six months. Higher rate of recurrent myocardial infarction and increased frequency of cardiac arrhythmia were observed.

DETO2X-AMI study randomly assigned 6629 patients with STEMI and oxygen saturation of 90% or more to either supplemental oxygen 6 liters per minute for 6-12 hours through an open face mask or ambient air. There was no reduction of one year mortality with oxygen administration in those without hypoxia.

The recommendation was that supplemental oxygen is indicated only if the oxygen saturation is less than 90% or partial pressure of oxygen is less than 60 mm Hg. Hyperoxia may be harmful in patients with uncomplicated STEMI, presumably due to increased myocardial injury.

References

1. Stub D et al; AVOID Investigators. Air Versus Oxygen in ST-Segment-Elevation Myocardial Infarction. Circulation. 2015 Jun 16;131(24):2143-50.
2. Hofmann R et al; DETO2X–SWEDEHEART Investigators. Oxygen Therapy in Suspected Acute Myocardial Infarction. N Engl J Med. 2017 Sep 28;377(13):1240-1249.