Abstract: Acute renal injury is a common complication of critically illness, which can significantly increase the mortality. Renal replacement therapy is an important measure to cure the patients with internal environment disturbance and indication of emergency dialysis, but without the indication of emergency dialysis, the optimal timing of initiating renal replacement therapy for acute renal injury remains uncertain. Although some previous studies have made preliminary exploration, they are either observational design, small sample size or selective bias. The evidence of existing evidencebased evidence does not support the specific benefit of early renal replacement therapy. We should consider multiple clinical indicators when making the decision to start renal replacement therapy.

Key words: acute kidney injury, renal replacement therapy, mortality, acute and critically illness