Renal Replacement Therapy in Acute Kidney Injury - Indication and Implementation

Abstract

Acute kidney injury (AKI) is a common complication in critically ill patients and is associated with a worse short- and long-term outcome. The KDIGO (Kidney Disease: Improving Global Outcomes) guidelines suggest to implement preventive strategies in high-risk patients. Definition and classification of acute kidney injury according to the KDIGO criteria are based on an increase in serum creatinine and/or a decrease in urinary output. Renal replacement therapy (RRT) is the only supportive measure in patients with severe AKI. The KDIGO guidelines recommend to initiate RRT immediately if an absolute indication exists. However, in the absence of absolute indication, there are no recommendations when to start RRT in AKI patients with a progressive decline of renal function. Continuous or intermittent techniques of renal replacement therapy may be used equally for treatment of acute kidney injury. In hemodynamically instable patients and patients with increased intracranial pressures continuous renal replacement therapy is recommended. Although weak evidence exists, regional citrate anticoagulation is suggested for patients receiving continuous renal replacement therapy and systemic heparin anticoagulation is suggested for patients receiving intermittent renal replacement therapy. The KDIGO guidelines recommend to deliver an effluent volume of 20 - 25 ml/kg/h for CRRT in AKI.