Can keeping blood pressure higher during surgery prevent organ damage?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * ≥45 years old * Scheduled for major noncardiac surgery expected to last at least 2 hours; * Having general endotracheal, neuraxial anesthesia, or the combination; * Expected to require at least overnight hospitalization; * Are designated ASA physical status 2-4 (ranging from mild systemic disease through severe systemic disease that is a constant threat to life); * Chronically taking at least one anti-hypertensive medication; * Expected to have direct blood pressure monitoring with an arterial catheter; * Cared for by clinicians willing to follow the GUARDIAN protocol; * Subject to at least one of the following risk factors: * 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; * Scheduled for major vascular surgery; * Body mass index ≥35 kg/m2; * Preoperative high-sensitivity troponin T \>14 ng/L or troponin I equivalent; * B-type natriuretic protein (BNP) \>80 ng/L or N-terminal B-type natriuretic protein (NT-ProBNP) \>100 ng/L Exclusion Criteria: * Are scheduled for carotid artery surgery; * Are scheduled for intracranial surgery; * Are scheduled for partial or complete nephrectomy; * Are scheduled for pheochromocytoma surgery; * Are scheduled for liver transplantation; * Require preoperative intravenous vasoactive medications; * Have a condition that precludes routine or tight blood pressure management such as surgeon request for relative hypotension; * Require beach-chair positioning; * Have end-stage renal disease requiring dialysis or estimated glomerular filtration rate (eGFR) \<30 ml/min; * Have a documented history of dementia; * Have language, vision, or hearing impairments that may compromise cognitive assessments; * Have contraindications to norepinephrine or phenylephrine per clinician judgement; * Have previously participated in this trial.