Renal replacement therapy
Once pharmacological treatment fails in Acute Kidney Injury patients and oligo-anuric kidney failure is established, RRT should be started.
The timing of Renal Replacement Therapy initiation is a point of debate, with some arguing for a survival advantage from starting dialysis early.
The largest randomized controlled trials (RCT) to date was unable to demonstrate a survival advantage. RRT may be initiated in response to electrolyte and acid-base imbalance, hypercreatininemia, and severe fluid overload that is unresponsive to pharmacological treatment.
RRT can be stopped when improvement in kidney function is clear as pointed out by increased urine output or decreased serum creatinine levels in patients with constant continuous renal replacement therapy (CRRT) dose.
A urine output of more than 400 mL/day or a creatinine clearance of 15 to 20 mL/min could allow CRRT withdrawal.
CRRT and intermittent hemodialysis (IHD) both present pros and cons; when correctly applied, both CRRT and IHD can achieve good metabolic control.
In randomized, controlled trials and meta-analyses, CRRT seems to be associated with more frequent kidney recovery in critically ill patients.
Together with CRRT and IHD therapies, some “hybrid therapies” have been proposed, such as sustained low-efficiency (daily) dialysis (SLED) and extended daily dialysis in which IHD techniques are adapted to provide longer dialysis sessions.
Some clinical trials have not found any difference between SLED and continuous veno-venous hemofiltration in terms of cardiovascular stability and mortality rates, but SLED seems to be associated with a shorter duration of mechanical ventilation.
Concerning the RRT dose, large multicenter, randomized, controlled trials have found no advantage to doses higher than 20 to 30 mL of effluent/kg per hour.
Clinicians should tailor RRT therapy of critically ill patients to provide the ideal blood purification treatment.