The current international Continuous Renal Replacement Therapy (CRRT) replacement fluid doses of 35 ml/kg/h is better, but the result is according to white people, black people . It is Whether the best amount of replacement fluid for Chinese people, it is unclear. Especially,there is little evidence about the optimal dose from randomized trials in Cardiac surgery associated acute kidney injury (CSA-AKI )required CRRT,According to the clinical situation, the design of replacement fluid to 25 ml/kg/h.The observation of two doses 14 days, 28 days, 90 days survival and renal function.

Acute kidney injury (AKI) is a major complication in patients with cardiac surgery and is an independent predictor of mortality. However, the optimal intensity of renal replacement therapy for such patients is still controversial. we randomly assigned the patients with Cardiac surgery-associated acute kidney injury (CSA-AKI) to continuous renal replacement therapy with different treatment dose (35ml / kg / h or 25ml/kg／h),The primary study outcome was death from any cause within 14, 28 and 90 days.

Inclusion Criteria:

• > = 18 years of age, CRRT indications for acute kidney injury (RIFLE criteria) patients with cardiac surgery

Exclusion Criteria:

• < 18 years old,
• with chronic kidney disease,
• dialysis history, to leave the ICU patients with acute kidney injury (AKI). - chronic kidney disease,
• all causes kidney damage (pathology, hematuria, and radiographic abnormalities)> = 3 months or glomerular filtration rate < 60ml/min for 3 months or more.