Low-dose Norepinephrine Infusion for Prevention of Post-induction Hypotension in Emergency Surgery for Peritonitis

Inclusion Criteria: * Adults aged 18 years or older. * Secondary peritonitis requiring emergency surgery under general anesthesia with endotracheal intubation. * Planned induction with fentanyl, propofol, and rocuronium according to the study protocol. * Hemodynamically stabilized after initial resuscitation, with MAP at least 65 mmHg and no ongoing vasopressor infusion before induction. * ASA physical status I to III. * Written informed consent from the participant or a legally authorized representative. Exclusion Criteria: * Allergy or contraindication to norepinephrine, propofol, fentanyl, or rocuronium. * Severe cardiovascular disease likely to confound hemodynamic assessment, including decompensated heart failure, acute coronary syndrome, severe arrhythmia, severe valvular disease, or major cardiomyopathy. * Ongoing vasopressor therapy before induction. * Shock before surgery, including hypovolemic, septic, or cardiogenic shock. * Severe hypertension before induction (systolic blood pressure \>180 mmHg or mean arterial pressure \>110 mmHg). * Severe peripheral vascular disease or clinically significant limb ischemia. * Current monoamine oxidase inhibitor use. * Pregnancy or breastfeeding. * Contraindication to arterial catheter placement. * Refusal of consent.