Although supplemental oxygen has long been considered standard care for patients with ACS, the evidence supporting this concept is largely based on animal studies in which acute MI was artificially induced. Should these studies be extrapolated to humans? Maybe not....
Further review of the animal and human literature actually indicates that the routine use of supplemental oxygen and induction of hyperoxia can actually induce adverse hemodynamic consequences such as increased coronary artery tone and reduction in coronary artery blood flow; reductions in cardiac output and increased systemic vascular resistance; and potentially increased infarction size. It certainly seems prudent to treat hypoxia, but if the patient is not hypoxic, skip the supplemental oxygen!
Wijesinghe M, et al. Routine use of oxygen in the treatment of myocardial infarction: systematic review. Heart 2009;95:198-202. AND Farquhar H, et al. Systematic review of studies of the effect of hyperoxia on coronary blood flow. Am Heart J 2009;158:371-377.
