Gelaspan vs Crystalloid Therapy in Sepsis

Inclusion Criteria: * Age ≥ 18 years. * Diagnosis of sepsis according to the Sepsis-3 definition, caused by intra-abdominal infection, and requiring emergency abdominal surgery for source control. * Sequential Organ Failure Assessment (SOFA-2) score ≥ 2 (determined by the most recent available clinical data) and blood lactate \> 2 mmol/L (measured within 6 hours prior to enrollment). * Subject or legal representative can understand the study purpose and provide written informed consent. Exclusion Criteria: * Received any dose of artificial colloids within 24 hours prior to randomization. * Predicted mortality within 48 hours (ASA physical status class ≥ V). * Atrial fibrillation or congestive heart failure. * Severe Acute Respiratory Distress Syndrome (ARDS). * Preoperative coagulation dysfunction or receiving anticoagulant therapy. * Preoperative requirement for renal replacement therapy (long-term or intermittent, including hemodialysis or peritoneal dialysis). * Acute burns exceeding 10% of the total body surface area. * Severe hepatic impairment. * Severe electrolyte disturbance. * Pregnancy or breastfeeding. * Known allergy to gelatin. * Current participation in other interventional clinical trials. * Other conditions that the investigator considers inappropriate for inclusion.