Indications to Start Kidney Replacement Therapy

In the absence of high-quality trials, no ­evidence-based criteria for the initiation of dialysis can be provided. A serum potassium > 6.5 mEq/l and/or ECG changes is a generally accepted threshold to initiate dialysis. Pulmonary edema and overt fluid overload are definite indications for kidney replacement therapy (KRT). Oliguria (diuresis < 200 ml/12 h) or anuria (diuresis < 50 ml/12 h) after optimization of volume status are generally accepted indications to start KRT. It remains unclear whether an earlier start of KRT, triggered by a less pronounced or less prolonged decline of diuresis, is beneficial. A trial of loop diuretics (furosemide 20 mg/h or bumetanide 1 mg/h) can be considered in volume-overloaded patients. Failure to increase diuresis to 0.5–1 ml/kg/h within a few hours should lead to prompt withdrawal of the diuretic and institution of dialytic support. A serum urea concentration of 190–215 mg/dl (32–36 mmol/l) is a commonly accepted threshold to initiate KRT. Whether earlier dialysis provides a survival advantage is unknown. The value of urea cutoff levels to initiate dialysis has been questioned. The use of biomarkers appears promising to predict the necessity of KRT, but still requires validation.