1. Sustained low efficiency daily hemodiafiltration(SLEDD-f) is a kind of renal replacement therapy with high-flux dialyser membrane (helixone).
2. The pore size of helixone is larger than most antibiotics, and vancomycin is supposed to be removed during dialysis.
3. Our study wants to find the amount of vancomycin removed during SLEDD-f, and try to find the most appropriate dose regimen for this kind of patients.

Vancomycin is the most important antibiotic in the treatment of resistant G(+) bacteria infections. Close monitor of serum level is important to ensure its safety and effectiveness. So far there is not enough data to support the optimal dose regimen of vancomycin in patients on SLEDD-f. In this study, we draw blood levels between 2 doses of vancomycin to determine the pharmacokinetic parameters of vancomycin and fraction removed by SLEDD-f so as to determine the most appropriate dose regimen.

Inclusion Criteria:

• Acute renal failure of any cause
• Use SLEDD-f as renal replacement therapy
• Priscribe vancomycin for a known or suspected infection

Exclusion Criteria:

• None

Patients in intensive care unit.