Effects of Variation of Sodium Dialysate in ICU

Intermittent hemodialysis/diafiltration is a current renal replacement therapy (RRT) institued for ICU patients with AKI. For a better clinical tolerance, iinternational guidelines advise to use cold dialysate, increase duration session, decrease blood and dialysate flows, and increase level of sodium dialysate concentration (≥ 145mmol/l). Indeed, the use of a Na concentration dialysate \> 145 mmol/l improves intradialytic hemodynamic tolerance but it may also induce fluid overload by the transfert of sodium from the dialysate compartment to the blood. Yet, fluid overload has been strongly associated with mortality in critically ills. The investigators hypothesized that the use of a level in sodium dialysate at 140 mmol/l with slow low efficiency daily dialysis-filtration (SLEDD-f) will permit a fair intradialytic hemodynamic tolerance without the adverse effect of intradiaclytic Na loading from the dialysate. Two randomized groups of ICU AKI patients treated by SLEDD-f will be compared in terms of intradialytic hemodynamic tolerance and overload accordong to 140 or 145 mmol/l of Na in the dialysate