This study tests whether giving a low-dose norepinephrine infusion just before induction of anesthesia can reduce low blood pressure during emergency surgery for peritonitis. Adults with secondary peritonitis who are scheduled for emergency surgery and have stable blood pressure after initial resuscitation will be randomly assigned to receive either norepinephrine or placebo (normal saline) during induction of anesthesia. The main outcome is the cumulative time spent with mean arterial pressure (MAP) below 65 mmHg from the start of propofol administration to 10 minutes after endotracheal intubation. The study will also evaluate rescue vasopressor use, heart rate changes, drug-related adverse events, and selected early postoperative outcomes.