Rational pharmacotherapy and experimental strategies in the treatment of acute renal failure -: Part II -: Extracorporal renal replacement therapy and peritoneal dialysis

Therapy of prolonged acute renal failure regularly requires a renal replacement therapy. This can be achieved by different extracorporal renal replacement therapies (ERRT) or by peritoneal dialysis. ERRT are classified according to the physical principle underlying toxin elimination as hemodialysis (diffusion) and hemofiltration (convection). Another classification refers to intermittent or continuous application modes. Biocompatibility of membranes is judged according to their activation of the complement system. Prospective randomized studies did not consolidate the assumptions about the benefit of particular modalities proposed on theoretical foundations. Mortality, duration and complication rates of acute renal failure are not significantly decreased by use of biocompatible membranes. Continuous modalities are not generally preferable but optimize treatment in hemodynamically unstable patients, in whom they endorse fluid balancing and maintenance of sufficient arterial blood pressure. The use of demanding hemofiltration techniques for cytokine removal should be limited to clinical studies. The effects of ERRT-"intensity" and the best timing for initiation of ERRT have not been evaluated sufficiently. The choice of the ERRT modality is subject to clinical judgement (criterion: hemodynamic situation), practical aspects (criteria: availability of equipment and handling experience), and costs. Prior to their general use new and expensive technical modalities and membrane types should be thoroughly evaluated in studies with regard to outcome-related aspects such as patient survival and preservation of renal function.