Supplemental Oxygen is Not Needed for STEMI Patients with Normal Oxygen Saturations
Ali S. Raja, MD, MBA, MPH, FACEP
Outcomes were either similar or worse for STEMI patients given supplemental
oxygen, compared with those who maintained a saturation ≥94% on their own.
Supplemental oxygen likely provides no benefit to — and may even harm — patients with chronic
obstructive pulmonary disease or other causes of dyspnea (NEJM JW Emerg Med Nov 2010 and BMJ
2010; 341:c5462 and Physician’s First Watch Sep 3 2010 and Lancet 2010; 376:784). However, it is used ubiquitously in patients with ST‐segment elevation myocardial infarction (STEMI) due to the ischemic nature of the disease. To date, several small studies have suggested that oxygen may not have any benefit in STEMI. To determine its effects, investigators in Australia conducted a randomized trial of supplemental oxygen versus room air in patients with out‐of‐hospital STEMI.
Oxygen (8 L/minute) and air were administered by paramedics and continued through the cath lab and into inpatient units. Patients in the control group did not receive oxygen unless their saturations dropped below 94%. Of 638 patients randomized by paramedics, 441 had confirmed STEMI on angiography and were included in the intention‐to‐treat analysis. The primary outcome was myocardial injury (as defined by troponin and creatine kinase levels).
Mean peak troponin levels were not statistically different in the two groups. However, the oxygen group had significantly higher mean peak creatine kinase values (1948 vs. 1543 U/L), higher rate of recurrent MI during hospitalization (5.5% vs. 0.9%) and greater increases in infarct size at 6 months on magnetic resonance imaging (20.3 vs. 13.1 grams.
At best, supplemental oxygen is not needed for patients with STEMI who are able to
maintain normal saturations. At worst, it may be harmful. Either way, this current mainstay treatment should be removed from the routine management of these patients.
Stub D et al. Air versus oxygen in ST-segment-elevation myocardial infarction. Circulation 2015 Jun 16; 131:2143. (http://dx.doi.org/10.1161/CIRCULATIONAHA.114.014494)
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