Assessing the Impact of Two Methods of Continuous Veno-venous Hemodiafiltration on Time Nursing Work in Intensive Care

The prevalence of acute renal failure in intensive care is estimated at between 5 and 20% depending on diagnostic criteria retained. And half of patients require the use of hemodialysis. Continuous veno-venous hemodiafiltration (CVVHDF) is one of the hemodialysis technique widely used in intensive care unit. The CVVHDF is performed at the bedside, by a mobile generator with a semi permeable membrane, a blood circuit, a dialysate circuit and a feedback circuit. The implementation of a CVVHDF requires the use of large amounts of biological liquid essential to enable the purification of blood during its passage through the artificial kidney. The biological fluid may be supplied to the generator of CVVHDF in 2 ways: * The conventional method, the most used: the generator operates with pockets containing dialysis fluid, these pockets to be changed regularly by nurses * The on-line method: the generator operates with a specific water system supplying the dialysis fluid available in every room of the unit The objective of this study is to assess time nursing work and the costs of each method. For this, 15 patients will be included in this study. Each patient performs 12 hours of each method (conventional and online), whose order will be randomized.