O2 for STEMI: Still Up in the Air
The development of American College of Cardiology/American Heart Association (ACC/AHA) clinical practice guidelines, based on a rigorous review and evaluation of the available evidence, has helped shape the field of cardiovascular medicine over the last 3 decades. In patients with ST-segment elevation myocardial infarction (STEMI), primary percutaneous coronary intervention (PCI) has emerged as the preferred reperfusion therapy, and shorter times to reperfusion have been associated with improved survival.1, 2 Based on an estimate of the size of the intervention and the magnitude of benefit in relation to risk, primary PCI for STEMI is given a Class I recommendation with Level of Evidence A, the latter based on the certainty or precision of the data and the type and quality of the evidence. For some treatments, little evidence exists, and their implementation is largely based on clinical experience, standard of care, and/or expert opinion. In the case of supplemental oxygen administration during STEMI, the ACC/AHA guideline recommendations have evolved. In 1999, while supplemental oxygen received a Class I recommendation for patients with pulmonary congestion and arterial oxygen saturation <90%, routine administration to all patients with uncomplicated myocardial infarction during the first 2-3 hours received a Class IIa recommendation.3 In the 2004 STEMI guidelines, continuing supplemental oxygen beyond the first 6 hours for hypoxemia (arterial oxygen saturation <90%) or pulmonary congestion was also given a Class I recommendation.4 However, the 2013 STEMI guidelines noted that few data exist to support or refute the value of the routine use of oxygen in the acute phase of STEMI, and no recommendation was made.5 Therefore, the risks and benefits of routine administration of supplemental oxygen during acute STEMI, in the absence of systemic hypoxemia, is an intervention for which evidence to inform our practice in the current era of reperfusion is lacking.
- Received May 14, 2015.
- Accepted May 14, 2015.