LCN2 and acute kidney injury: Secondary evaluation outcomes include changes in blood urea nitrogen (BUN), estimated glomerular filtration rate (eGFR), urinary AKI biomarkers (neutrophil gelatinase-associated lipocalin (NGAL), interleukin-18 (IL-18), gamma-glutamyl transpeptidase (γ-GT), etc.), traditional Chinese medicine (TCM) symptoms, inflammatory indicators, and oxidative stress indicators.