[Renal replacement therapy in intensive care medicine : Overview of the new S3 guidelines]

The publication in 2025 of the first S3 level guidelines on renal replacement therapy (RRT) in intensive care medicine provides the comprehensive, evidence-based recommendations for critically ill patients with acute kidney injury (AKI). They define absolute indications that require the immediate initiation of RRT. Acute kidney injury (AKI) requiring RRT is common in the ICU and is associated with increased mortality. A narrative review of the new guidelines was performed by extracting and appraising recommendations on initiation, modality selection, anticoagulation, dosing, anti-infective therapy, weaning and post-ICU follow-up. Immediate RRT is mandated for absolute indications, such as life-threatening and refractory hypervolemia, electrolyte, acid-base or uremic disturbances. In the absence of these, a proactive early start is advised if the overall clinical picture (comorbidities, disease trajectory and the patients current condition) suggests a high likelihood of RRT becoming necessary. In other cases, a conservative management is possible. Continuous and intermittent techniques are considered therapeutically equivalent, whereby continuous or prolonged procedures are given priority in cases of hemodynamic instability. In cases of severe hyperkalemia a diffusive procedure with high dialysis flow is recommended. Regional citrate anticoagulation is preferred in patients with a risk of bleeding. For continuous RRT an effluent dose of 20-25 ml/kg body weight h^-1 is advised, whereas intermittent dosing is individualized without a fixed target. In anti-infective treatment the initial dose should not be reduced and is given as short infusions. The role of dose-adjustment tools and therapeutic drug monitoring are emphasized. Before a weaning attempt, volume overload, hyperkalemia and metabolic acidosis should be corrected. The return to spontaneous diuresis is the most reliable predictor for successful weaning. Stable renal function for at least 7 days defines the primary success of weaning. All survivors of AKI should receive structured outpatient follow-up after hospital discharge. The new guidelines provide for the first time integrated recommendations for action for RRT in the critically ill, aiming to improve the quality of treatment and standardization in German-speaking intensive care units.