Oxygen therapy is administered to all patients during general anesthesia to maintain tissue oxygenation and prevent hypoxia and ischemia. However, liberal use of oxygen may lead to hyperoxia and some studies suggest that supranormal levels of arterial oxygen saturation may lead to complications. In this post hoc substudy of the VISION cohort, we plan to assess the association between perioperative inspired oxygen fraction (FiO2) and myocardial injury after non-cardiac surgery (MINS).

Patients will be divided into five groups of median intraoperative FiO2 (quintiles), in which baseline characteristics and outcomes will be illustrated.

The odds ratio (OR) for the primary and secondary outcomes will be calculated in a logistic regression analysis with median FiO2 (continuous variable) as independent variable.

Analyses are performed with multiple logistic regression with adjustment for the following potentially confounding variables:

Age ≥75 years. Male sex. Current atrial fibrillation. History of diabetes. History of congestive heart failure. History of coronary artery disease. History of recent (i.e., < 6 months) high-risk coronary artery disease. History of stroke. History of peripheral vascular disease. History of hypertension. Preoperative eGFR (<30 vs. 30-44 vs. 45-59 vs. ≥60 mL/min/1.73m2). Low-risk surgery. Duration of surgery.

Inclusion Criteria:

• Patients entered in the VISION database, aged 18 years or above, undergoing noncardiac surgery in general anesthesia.

Exclusion Criteria:

• Patients with unobtainable data on perioperative FiO2.
• Patients with unobtainable data on postoperative troponin.

All patients entered in the VISION database, undergoing noncardiac surgery in general anesthesia.