Oxygen therapy in acute coronary syndrome: are the benefits worth the risk?
Mony Shuvy1,*, Dan Atar2,3, Philippe Gabriel Steg4, Sigrun Halvorsen2, Sanjit Jolly5, Salim Yusuf5 and Chaim Lotan1

Abstract

Oxygen supplementation is a standard treatment for all patients who present with acute coronary syndrome, regardless of oxygen saturation levels. Most of the data regarding the function of oxygen in myocardial infarction is based on a limited number of basic and clinical studies.
We performed a systematic literature review that explores the basic and clinical data on the function of oxygen in ischaemic heart disease and myocardial infarction.
This review discusses many aspects of oxygen treatment: (i) basic studies on the effects of oxygen in ischaemia and the potential cardiovascular effects of oxygen metabolites; (ii) clinical trials that have assessed the value of inhaled oxygen, supersaturated oxygen, and intracoronary injection of hyperoxaemic solutions in myocardial infarction; and (iii) the haemodynamic effects of oxygen in various clinical scenarios and its direct effects on the coronary vasculature.
Our findings suggest that there are conflicting data on the effects of oxygen treatment. Further, the potential harmful effects of oxygen must be considered, particularly in myocardial infarction. These findings question the current guidelines and recommendations and emphasize the need for large clinical trials

DISCUSSION

Oxygen is readily available and easy to use. Those who recommend routine oxygen therapy argue that oxygen therapy is harmless.44 A recently published survey evaluated the physician’s rationale for using oxygen in MI patients—approximately half of respondents believed that oxygen decreases mortality, while 25% believed that it reduces pain. Although 25% of physicians stated that oxygen has no effect, 96% of them chose to use oxygen in MI patients.45

The cost of oxygen treatment in patients with ACS needs to be examined. Basic calculations suggest that in-hospital oxygen treatment costs up to $10 per day—higher in the pre-hospital setting—translating into a significant cumulative financial burden.

Recently, several scientific societies have reviewed and modified their guidelines on ACS management regarding oxygen supplementation—the new European guidelines now recommend oxygen therapy only in hypoxaemic patients.7,8 Also, the Scottish Intercollegiate Guidelines Network and the British National Clinical Guidelines Centre for acute and chronic conditions advocate oxygen therapy only in hypoxic patients (SaO2 <94%). These new revisions, however, are based on expert opinion (level C), not solid clinical data.

Ref: EUROPEAN HEART JOURNAL 2013-34-22.

G.MOHAN.