Although monitoring fluid balance for continuous renal replacement therapy-treated patients is an important issue, most physicians usually use conventional methods such as the difference between the amount of intake and output (I & O), which is not objective way. Meanwhile, bioimpedance electrical vector analysis presents the patients' fluid status with more objective data. Thus, the investigators will investigate the clinical benefit for monitoring fluid balance when the investigators use InBody S10, one of representative bioimpedance electrical vector analysis, compared with conventional methods among the patients who need continuous renal replacement therapy.

Although monitoring fluid balance for continuous renal replacement therapy-treated patients is an important issue, most physicians usually use conventional methods such as the difference between the amount of intake and output (I & O), which is not objective way.

Meanwhile, bioimpedance electrical vector analysis presents the patients' fluid status with more objective data.

Thus, the investigators will investigate the clinical benefit for monitoring fluid balance by using InBody S10 (0, 1, 2-day, and 7-day from CRRT initiation), one of representative bioimpedance electrical vector analysis, compared with conventional methods among the patients who need continuous renal replacement therapy.

Inclusion Criteria:

• Patients will be eligible for INCLUSION in the study if ALL the following criteria are met;

  1. The treating clinician believes that the patient requires continuous renal replacement therapy for acute renal failure.

  2. The treating clinicians anticipate treating the patient with continuous renal replacement therapy for at least 72 hours.

  3. Informed consent has been obtained.

  4. The patient fulfills ONE of the following clinical criteria for initiating continuous renal replacement therapy:

     urine output < 100 ml/6 hr that has been unresponsive to fluid resuscitation measures

     • K+> 6.5 mmol/L
     • pH < 7.2
     • Urea > 25 mmol/L
     • Clinically significant organ edema in the setting of acute kidney injury

  5. Patients who are over 5% of fluid overload or their total body water/height^2 ≥13 L/m^2

     Exclusion Criteria:

• Patients will be EXCLUDED from the study if, in the opinion or knowledge of the responsible clinician ANY of the following criteria are present:

  1. Patient age is < 18 years
  2. Death is imminent (<24 hours)
  3. There is a strong likelihood that the study treatment will not be continued in accordance with the study protocol.
  4. The patient has been treated with continuous renal replacement therapy or other dialysis previously during the same hospital admission.
  5. The patient has been on maintenance dialysis prior to the current hospitalization.
  6. Any other major illness that, in the investigator's judgement, will substantially increase the risk associated with the subject's participation in this study.