Clin Nephrol
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Continuous renal replacement therapies are extensively utilized for the treatment of acute renal failure in the critically ill patient. The arterio-venous circulation has been partially substituted by the veno-venous pump driven circulation. Diffusion has been added to convection in order to increase the small solutes clearance even though sometimes the pure convection is still advantageously utilized. ⋯ The improved understanding of the multiple organ failure syndrome and the pathophysiology of the septic syndrome, suggest today newer indications for continuous renal replacement therapies. The proposed mechanisms of action of the therapy should be the removal of chemical mediators such as platelet activating factor, interleukin-1 and tumor necrosing factor alfa, not only by a filtration process, but also by the adsorption on the surface and structure of the artificial membrane. These new mechanisms may in part be responsible for the beneficial effects of continuous therapies in the patients affected by acute renal failure and other organ dysfunctions.