Dialysis modality and dosing strategy in acute renal failure

Many fundamental aspects of the management of renal replacement therapy (RRT) in acute renal failure (ARF) remain unresolved. While data from multiple studies support the initiation of RRT, in the absence of other indications, when the BUN has reached a level of approximately 90-100 mg/dl, there are conflicting data regarding the benefit of earlier initiation of renal support. The relative efficacy of the various RRT modalities is uncertain. Despite growing utilization, a survival benefit or greater recovery of renal function has not been demonstrated for continuous renal replacement therapy (CRRT) as compared to conventional intermittent hemodialysis (IHD). Optimal dosing strategies are also poorly defined. While there is increasing evidence that more intensive renal support is associated with better outcomes in ARF, an optimal Kt/Vurea and treatment frequency for IHD remain to be established. Similarly, although data suggest that continuous venovenous hemofiltration (CVVH) should be dosed at no less than 35 ml/kg/hr (postdilution), confirmation of this dosing strategy and validation for other modalities of CRRT are required.