Inclusion Criteria:  Scheduled for major non-cardiac surgery Having general anaesthesia Are designated ASA physical status ≥2 (ranging from mild systemic disease through severe systemic disease that is a constant threat to life)  Subject to at least one of the following risk factors:  Age ≥ 65 years History of peripheral arterial surgery History of coronary artery disease History of stroke or transient ischemic attack Serum creatinine >175 µmol/L (>2.0 mg/dl) Diabetes requiring medication Current smoking or 15 pack-year history of smoking tobacco Preoperative high-sensitivity troponin T >14 ng/L or troponin I equivalent, defined as ≥15 ng/L (Abbott assay),75 19 ng/L (Siemens assay, [Borges, unpublished]), or 25% of the 99% percentile for other assays; B-type natriuretic protein (BNP) ≥ 80 ng/L or N-terminal B-type natriuretic protein (NT-ProBNP) ≥ 200 ng/L.76,77 History of atrial fibrillation Chronically taking at least one anti-hypertensive medication  Exclusion Criteria:  Are scheduled for carotid artery surgery Are scheduled for intracranial surgery Are scheduled for pheochromocytoma surgery Require preoperative intravenous vasoactive medications Active decompensated congestive heart failure (documented EF < 30%) Chronic Kidney Disease (eGFR< 30 mL/min) History of organ transplantation Rectal surgical procedures Patients receiving preoperative bowel preparation Severe pulmonary edema