Intraoperative hypotension is commonly treated with fluid administration; however, excessive fluid therapy may contribute to postoperative pulmonary complications. This randomized double-blind controlled trial evaluates whether proactive administration of fixed low-dose norepinephrine reduces intraoperative crystalloid administration while maintaining hemodynamic stability in high-risk patients undergoing laparoscopic abdominal surgery. One hundred and thirty patients will be randomized to receive either norepinephrine infusion (0.03 µg/kg/min) or placebo from induction until skin closure within a protocolized hemodynamic strategy guided by mean arterial pressure and pulse pressure variation.
Adult patients aged 18 years or older.
American Society of Anesthesiologists (ASA) physical status I-III.
Scheduled for elective laparoscopic major abdominal surgery under general anesthesia with an expected duration greater than 2 hours.
Patients with ARISCAT score ≥ 45 indicating high risk for postoperative pulmonary complications.
Known hypersensitivity to norepinephrine.
Severe left ventricular dysfunction with ejection fraction < 35%.
Significant cardiac arrhythmia.
Uncontrolled hypertension defined as systolic blood pressure ≥ 180 mmHg or diastolic blood pressure ≥ 110 mmHg.