The trial is a prospective, randomized, single-blind, pilot study investigating whether near-infrared spectroscopy (NIRS)-guided optimization of intraoperative renal oxygen saturation reduces postoperative acute kidney injury (AKI) in patients undergoing elective hepatectomy. The trial will enroll 80 adults (≥45 years, American society of Aneshesiologists physical status I-III), randomizing them to either standard anesthesia management or NIRS-guided management where a predefined 6-step intervention protocol (volume optimization, vasoactive drugs, inotropes, heart rate management, transfusion, and FiO₂ management) is triggered if decreases >10% from baseline. Primary outcomes are the incidence of AKI within 7 days and the 28-day Comprehensive Complication Index (CCI). The study aims to determine if real-time SrtO₂ monitoring and proactive intervention can prevent this serious complication, based on previous observational data linking renal desaturation to AKI risk.

Inclusion Criteria:

• Age ≥ 45 years
• Scheduled for elective hepatectomy
• Planned for general anesthesia with endotracheal intubation
• BMI < 30 kg/m2
• Preoperative ultrasound shows renal cortical to skin distance ≤ 4 cm
• ASA classification I-III
• Consenting to participate and signing informed consent

Exclusion Criteria:

• Liver transplantation surgery
• Preoperative renal dysfunction or requirement for dialysis treatment;
• Contraindications to vasoactive drugs such as norepinephrine or dopamine as determined by the clinician;
• Severe cardiopulmonary insufficiency (severe arrhythmia, heart failure, respiratory failure, chronic obstructive pulmonary disease), or a serious cardiovascular or cerebrovascular event within the last six months before randomization (such as acute heart failure, acute myocardial infarction, stroke, etc.);
• Patient refusal to participate or current participation in another experimental study;
• Other factors deemed unsuitable for inclusion by the researcher.