Experts have recommended doing away with the routine use of supplemental oxygen in patients with suspected MI after a new study has revealed it offers no benefit in patients without hypoxia.

The firmly entrenched practice has come under fire in recent years because of the surprising lack of evidence to support its use. Concerns were also raised from the Australian AVOID trial that found supplemental oxygen was linked to larger infarct sizes in treated patients compared to patients who were not given the therapy.

Now results from the Determination of the Role of Oxygen in Suspected Acute Myocardial Infarction (DETO2X-AMI) trial, which challenged the standard practice of giving oxygen to patients without hypoxemia, has found there is no impact on 1-year mortality with oxygen compared to ambient air.

While there was no harm, oxygen therapy offered no benefit across any of the pre-specified subgroups, including patients with confirmed STEMI.

Additionally, the extent of myocardial injury, as assessed by cardiac troponin T levels, was no different between patients who received supplemental oxygen and those who did not.

The findings from the registry-based randomised trial have been described as ‘definitive’ and enough to support a change in clinical practice.

Writing in an editorial accompanying the paper Dr Joseph Loscalzo, from Brigham and Women’s Hospital in Boston in the US said that while mechanisms underlying the lack of benefit were complex, the results of the study are straightforward and indisputable: “supplemental oxygen provides no benefit to patients with acute coronary syndromes who do not have hypoxemia—it is clearly time for clinical practice to change to reflect this definitive evidence.”