Renal Resistive Index in Early Detection of Postoperative Acute Kidney Injury

Inclusion Criteria: * Elective cardiac surgeries under general anesthesia with prolonged CPB (\>70 min) and aortic cross clemp (\>60 min) time * \>18 years of age, without preoperative acute or chronic renal failure * with preoperative and postoperative RRI measurements Exclusion Criteria: * Patients with known renal insufficiency, * Patients with acute renal failure in the last 3 months * Emergency surgeries, * Patients with arrhythmia end-stage renal disease and renal transplant * Patients Patients with short duration of CPB (\<70 min) and ACK (\<60 min) * Failed Doppler ultrasonography imaging