The frequency of preoperative cardiac ischemia and the 30-days postoperative mortality is much higher than previously assumed, with approximately 10 % of patients undergoing non-cardiac surgery suffering from postoperative myocardial injury. A recent danish study furthermore showed that patients treated with a high inspiratory oxygen fraction during surgery had a higher 1 year mortality compared with patients treated with a low inspiratory fraction. This was especially significant among patients undergoing cancer surgery. A possible explanation, is that a high oxygen fraction results in oxidative stress and endothelial dysfunction.