Acute renal replacement therapies in critically ill patients

Acute kidney injury (AKI) is defined as the abrupt deterioration of renal excretory function, often observed in critically ill patients. The incidence of AKI worldwide ranges between 20 and 200 cases per million population. Sepsis and septic shock contribute to 25-75% of AKI cases. Regardless of the cause, loss of fluid and electrolyte homeostasis and the accumulation of nitrogenous wastes lead to uremia, hyperkalemia, water and sodium retention, and metabolic acidosis. Renal replacement therapies (RRT) aim to mitigate these effects and prevent death associated with kidney failure. There are various modalities of RRT, including intermittent hemodialysis, continuous RRT, as well as different solute elimination techniques. There have been significant advances in membrane technologies and the addition of substances to improve biocompatibility, in addition to new anticoagulation strategies. The aim of this article is to review current RRT alternatives and comment on recommendations regarding their dosage and timing for starting and discontinuing therapy.