[Research progress of renal resistive index in the evaluation of acute kidney injury].

Acute kidney injury (AKI) is common in critically ill patients and it is directly related to the patient's prognosis and survival. Despite remaining uncertainties regarding the prevalence of AKI in intensive care unit (ICU), the overall incidence of AKI is relatively high, and prompt recognition is necessary to ensure the risk assessment, early diagnosis, clinical outcome, and treatment of critically ill patients. Doppler-based renal resistive index (RRI) mainly reflects vascular bed resistance state, which can be indirect to the extent of the damage of renal parenchyma. It is a relatively objective and quantitative evaluation, and is widely used in clinical prognosis of acute or chronic renal damage evaluation and judgment. This paper reviews the definition of RRI, the measurement methods of RRI, the application and progress of RRI in the field of AKI, the advantages and disadvantages of ultrasonic measurement of RRI, the long-term application of RRI, the effectiveness of RRI in predicting AKI, and the progress in clinical application.