Maintaining Intraoperative Mean Arterial Pressure at 85 mmHg or Higher to Reduce Postoperative Delirium in Older Patients With Arterial Hypertension Having Non-cardiac Surgery

Inclusion Criteria: To be eligible for trial inclusion, patients must: * 1\) be able to provide informed consent, AND * 2\) be ≥65 years old, AND * 3\) be scheduled for elective non-cardiac surgery with general anesthesia that is expected to last ≥120 minutes, AND * 4\) have chronic arterial hypertension requiring antihypertensive medication OR have a systolic arterial pressure ≥140 mmHg or diastolic arterial pressure ≥90 mmHg on a measurement performed within the previous year, AND * 5\) be at high risk for postoperative delirium because: American Society of Anesthesiologists physical status class III or IV OR Charlson Comorbidity Index ≥3 points (please see Appendix 1) OR frailty (documented in medical records or clinical diagnosis) Exclusion Criteria: Patients that meet one or more of the following exclusion criteria cannot participate in the trial: * solid organ transplant surgery * intracranial surgery * surgery in sitting position * sepsis * surgery in the previous 30 days * previous participation in ASPIRE-85