[Renal replacement therapy in acute renal failure]

Acute kidney injury (AKI) is characterized by a sudden breakdown of the incretoric and excretoric functions of the kidneys. In intensive care it is always part of a multiple organ failure (MOF). It has a high incidence in intensive care (5 - 20 %), increasing up to 50 % in patients with septic shock. Its prognosis is variable (mortality 20 - 80 %) due to the fact, that up to the establishing of RIFLE and AKIN no consistent classification existed. Early start of extracorporeal treatment may lead to a reduced mortality in critically ill with AKI and MOF as the negative influence of AKI on other vital function disturbances may be reduced. Independent of the treatment form, all critically ill need a dosage of dialysis enabling negative effects of the hypercatabolic situation for these patients. An increase of the dosage over these demands did not lead to a better survival in the inhomogeneous group of all patients with AKI and MOF. In continuous forms of treatment an exchange amount of 20 ml/kg/h should be reached, as in intermittent hemodialysis a Kt/V lower 4 - 4.5/week should be avoided. According to the survival of the patients there is no evidence that either continuous forms of treatment or intermittent dialysis is superior over the other, comparing always these heterogeneous groups of medical and surgical AKI patients. There seems to be a small group of patients (mortality > 80 %) never included in any prospective randomized trial which can only be treated continuously.