Characteristics of Renal Blood Flow in AKI Patients in ICU and Its Clinical Significance

Inclusion Criteria: * Age between 18-85 years old; Control group: patients with non-acute kidney injury after ICU general surgery; Observation group: patients who met the diagnostic criteria of AKI: Scr elevation ≥26.5 umol/L within 48h; Scr elevation exceeding 1.5 times and more than the basal value within 7d; and decrease in urine output (\<0.5 ml/kg/h) with a duration of 6h or more. Exclusion Criteria: * Those who did not meet the inclusion criteria or refused to be enrolled; patients with underlying end-stage renal disease or requiring long-term dialysis; renal transplant patients; patients with other underlying systemic diseases causing renal dysfunction (SCr \> 88.4 umol/L); those who were unable to obtain a clear renal ultrasound view; those with suspected contrast allergy; those with pulmonary arterial systolic blood pressure ≥ 90 mm Hg; and those who were pregnant or breastfeeding women.