[Extrarenal purification techniques in acute kidney failure].

During the last few years much progress has been achieved in extrarenal blood purification, notably since continuous dialysis techniques have been developed. All forms of acute renal failure can now be treated specifically and safely. Conventional haemodialysis is still widely used, particularly when acute renal failure is of long duration or when it occurs in a context of renal disease. Continuous blood purification is in full development: it is relatively easy to perform, well tolerated in terms of haemodynamics and better than haemodialysis in modulating fluid subtraction. It has become the method of choice in high-risk patients, notably elderly people or subjects with multiple visceral impairment. These advances have made it possible to treat efficiently a greater number of patients, but the benefit obtained must be evaluated in relation to a prognosis which is still determined by the acute renal failure. When several organs are involved, the mortality rate is above sixty percent.