RecruitingProcedureThe GUARDIAN TrialAn international randomized trial to test the primary hypothesis that perioperative tight blood pressure management reduces a composite of major perfusion-related complications (myocardial injury, stroke, non-fatal cardiac arrest, Stage 2-3 acute kidney injury, deep or organ-space infection, sepsis, and death) in the 30 days after major non-cardiac surgery. The treatments will be: 1) norepinephrine or phenylephrine infusion to maintain intraoperative MAP ≥85 mmHg (tight pressure management); or, 2) routine intraoperative blood pressure management (routine pressure management).