Taking the Air Out of Oxygen Supplementation in Individuals With Diabetes and Acute Coronary Syndromes.

Abstract

Oxygen supplementation has been a cornerstone in the initial treatment of individuals with acute coronary syndrome. While consensus for oxygen supplementation exists for patients with hypoxia, oxygen supplementation has also been routinely used in those presenting with acute myocardial infarction (MI) with normal oxygen saturations based on the rationale that oxygen therapy could improve oxygen supply to the ischemic myocardium, thereby reducing the infarct size and complications. Indeed, reports of oxygen supplementation to relieve angina pectoris were described as early as 1900 (1). These reports were followed by small studies that suggested benefit with oxygen supplementation in acute MI, but these studies were limited by lack of randomization and unblinded end point ascertainment (2–4). Nonetheless, supplemental oxygen was incorporated into routine clinical practice, as evidenced in 2007 cardiology practice guidelines that recommended routine supplemental oxygen to all patients with acute coronary syndrome during the first 6 h after presentation (5). This widespread belief in oxygen was highlighted in a survey of emergency department, cardiology, and ambulance staff in which 98% of respondents reported using oxygen supplementation for suspected MI and 55% believed oxygen reduced the risk of death (6). Despite the ubiquitous use of oxygen, there were early reports of potential harm with high-dose oxygen supplementation in individuals with acute MI (7). Over 40 years ago, the first randomized trial of high-dose oxygen in patients with an acute MI demonstrated that oxygen-treated patients had …