Association Between Early FiO₂ Exposure and Changes in the Uric Acid/Albumin Ratio in Septic ICU Patients

Inclusion Criteria: * Adult patients aged 18 years or older * Admission to the intensive care unit with a diagnosis of sepsis according to Sepsis-3 criteria * Receipt of oxygen therapy with FiO₂ ≥ 0.3 during ICU stay * Availability of serum uric acid, albumin, and lactate measurements and calculated SOFA scores at ICU admission * Availability of serum uric acid and albumin levels both at ICU admission (baseline) and at 24 hours * Provision of informed consent by the patient or a legally authorized representative Exclusion Criteria: * Age younger than 18 years * Pregnant or breastfeeding women * Chronic kidney disease or receipt of renal replacement therapy * Advanced liver failure (Child-Pugh class C) * Receipt of albumin infusion within the previous 24 hours * Use of medications that affect uric acid metabolism (e.g., allopurinol, febuxostat, rasburicase) * History of active gout attack or malignancy-related hyperuricemia * Missing serum uric acid or albumin measurements at baseline or 24 hours * Inability to obtain informed consent from the patient or a legally authorized representative