Renal replacement therapy for acute renal failure in the ICU

The most serious forms of acute renal failure (ARF) are nowadays encountere d in the intensive care unit (ICU), where up to 25% of new patients are rep orted to develop ARF. Lethality rates may reach 50 to 90% when the ARF is p art of a multiple organ dysfunction syndrome. A multitude of extracorporeal procedures have been introduced into intensiv e care medicine. Applied with adequate skills and experience, most of these techniques will suffice to replace excretory renal function. However, beca use of low efficacy arterio-venous procedures (CAVH and CAVHD) have been ab andoned for the veno-venous, pump-driven techniques (CVVH and CVVHD). Up to now, there is no consensus whether continuous or intermittent renal replac ement therapy is more advantageous. In many cases, oliguric patients with c irculatory instability will be treated by CVVH, even though there is no pro spective study to show that in terms of outcome continuous treatment is sup erior to intermittent hemodialysis. It is equally conceivable to treat such patients with daily, prolonged (intermittent) hemodialysis. Apparently, ly , the dose of replacement therapy, be it continuous filtration (36 to 481/2 4 h) or intermittent hemodialysis (daily 3 to 4 h) with a target BUN of les s than 50 mg/dl, is more important than the modality of treatment, Moreover , there is good evidence that the use of biocompatible membranes (no comple ment- or leukocyte activation) is preferable and that with high-volume hemo filtration bicarbonate-containing replacement fluids should be used. However, despite all the technical advances, we firmly believe that the ski lls; and the experience of those physicians and nurses who actually perform renal replacement therapy in the ICU are more important than the modality of treatment applied.