Hemodynamic Effects of Variations in Net Ultrafiltration Rate During Continuous Renal Replacement Therapy.

Renal renal replacement therapy (RRT) for severe acute kidney injury is one of the most widely used life-support techniques in intensive care. One of its main functions is to maintain the water balance in oligo-anuric patients by means of net ultrafiltration (NUF), defined as the volume of water removed from the patient by the RRT per unit time and indexed to the patient's weight. Surprisingly, the setting of this parameter, which is one of the most important, there are no guidelines. If net ultrafiltration is too low, it may prolong RRT dependency and length of stay in the ICU, with all the associated care-related complications, and increase mortality. If net ultrafiltration is too high, it may transiently induce hypovolemia, leading to hemodynamic instability related to renal replacement therapy (HIRRT). A recent survey of French practices shows that the average NUF flow rate used in intensive care units in France is 119 ± 77 ml/h, and the median flow rate is 100 ml/h \[min-max 20-300\]; in this study, NUF was not indexed by weight, but for a patient with an average weight of 75 kg, corresponding to an average NUF of 1.6 ± 1 ml/kg/h. In the NEPTUNE study, the investigators aim to compare the hemodynamic effect of three net ultrafiltration rates during RRT: 1 ml/kg/h, 2 ml/kg/h and 3 ml/kg/h. These three flow rates are within the range of those usually used in clinical practice.The research hypothesis is that one of the three flow rates evaluated induces the fewest hemodynamic instabilities related to RRT, while guaranteeing the best possible fluid balance.