Norepinephrine Prevent Post-induction Hypotension in High-risk Patients

Inclusion Criteria: * Patients aged above 65 years or those above 45 years with at least one of the following preoperative cardiovascular diseases: essential hypertension, coronary artery disease, stroke, or type I/II diabetes mellitus. * Patients who will receive major noncardiac surgery as open or laparoscopic abdominal surgeries with an anticipated operative duration over two hours, including gastrointestinal, liver, pancreatic, bladder, and uterine/adnexal surgeries. Exclusion Criteria: * Patients who declined to participate in the present study. * Patients enrolled in another ongoing clinical study. * Patients with systolic arterial pressure (SAP) below 90 mmHg or above 160 mmHg, or heart rate (HR) over 100 beats per minute (bpm) before anesthesia induction. * Patients who have experienced any type of shock within 30 days before surgery. * Patients with circulatory instability require continuous or intermittent positive inotropic and/or vasopressors within 24 hours before surgery. * Patients receive continuous or intermittent intravenous antihypertensive agents within 24 hours before surgery. * Patients underwent coronary artery bypass grafting, coronary angiography, or coronary stenting within 180 days before surgery. * Patients who were diagnosed with new-onset tachyarrhythmia within 180 days before surgery, such as atrial fibrillation, atrial flutter, and premature ventricular contractions. * Patients with preoperative alanine aminotransferase \>80 international units and/or glomerular filtration rate \< 80 ml/min within the 180 days before surgery. * Patients are ineligible for intraoperative invasive radial artery blood pressure monitoring. * Patients with a known history of allergy to norepinephrine. * Patients who were planned for rapid sequence induction. * Patients who were scheduled for awake tracheal intubation. * Patients who were scheduled for double-lumen endotracheal intubation. Pregnant or lactating patients.