Urinary Parameters to Predict Weaning of Renal Replacement Therapy in the Critically Ill

Data on the optimal period for RRT weaning in critically ill patient are scarce. The current practice for RRT weaning is based on urine output, the threshold of which is debatable. Two recent observational studies have shown that an increase in urinary creatinine or urea concentrations is a better predictive marker of RRT weaning than urine output. An unjustified delay in RRT weaning leads to numerous complications such as catheter-related infections, delay of the patient\'s functional recovery, severe ionic disorder, bleeding, and induced hemodynamic instability. It also induces an increase workload for careers and in cost without any additional benefit for the patient. Conversely, too early weaning inevitably limits the prevention on fluid accumulation that is independently associated with an increased risk of mortality and inevitably leads to resumption of RRT requiring reinsertion of dialysis catheter resulting in potential complications. A multicentre randomized controlled trial will be then necessary and only able to identify the optimal RRT weaning strategy. The main objective is to compare two RRT weaning strategies on RRT duration in critically ill patients with acute kidney injury: a strategy based on combined criteria (urine output + urinary parameters) as compared to a single strategy based only on urine output. The study protocol will be an open-label, two parallel group, multicenter, randomized, controlled clinical trial, in which enrolled ICU adult patients will have RRT weaning based either on urine output alone (single strategy) or on urine output and urinary parameters (combined strategy). When the urine output is greater than 500ml/24h, the enrollment must be performed within 24hours in 2 groups:. \" Single strategy \": In the single strategy, RRT weaning will be achieved when urine output exceeds 500ml/24h without diuretics or 2000ml/24h with diuretics use. \" Combined strategy\": In the combined strategy, when urine output exceeds 500ml/day with or without diuretic use, RRT will be stopped during 48h to assess urinary indices (urinary creatinine and urea). Soon as urinary indices are higher than thresholds values (urinary creatinine \> 5.2mmol/day and urinary urea \> 1.35mmol/kg/day, RRT will be weaned. If they are lower, a RRT session will be perform after which the weaning process will be resume. The primary endpoint is the number of RRT-free days at D30 with at least 7 consecutive days alive and without RRT.