CONTINUOUS RENAL REPLACEMENT THERAPIES - AN UPDATE

Continuous renal replacement modalities have found widespread use and acceptance over the last decade. The various modalities differ in the kind of access (arteriovenous v venovenous); in the application of con vective clearance (continuous hemofiltration), diffusive clearance (co ntinuous hemodialysis), or a combination of both (continuous hemodiafi ltration); and in the location where the replacement fluid enters the circuit (predilution v postdilution), Continuous therapies incorporate several advantages, such as improved hemodynamic stability, the possi bility for unlimited alimentation, optimal fluid balance, and gradual urea removal without fluctuations. However, it has not yet been shown whether these advantages have a significant impact on outcome and prog nosis, the ultimate measure of treatment efficiency. Major disadvantag es of continuous therapies are the ongoing necessity for continuous an ticoagulation, immobilization of the patient, and possible side effect s from lactate-containing replacement fluid or dialysate, Continuous r enal replacement procedures have certainly made the management of crit ically ill patients easier, In particular, oligoanuric patients with d iuretic resistant volume overload and hemodynamically unstable patient s with acute renal failure and concomitant sepsis or multiorgan failur e appear to benefit most from continuous treatment. The role of contin uous hemofiltration as a method of removing serum cytokines in septic patients without renal failure is still controversial and needs furthe r clinical assessment. Due to slow efficacy, continuous renal replacem ent is indicated only in rare circumstances for intoxication; this the rapy also is of rather limited use in severe hyperkalemia or acidosis. Noncritically ill patients with uncomplicated renal failure (eg, due to the use of dye or antibiotics) should be treated with intermittent hemodialysis or peritoneal dialysis. Furthermore, intermittent hemodia lysis is preferable in patients with hemorrhagic diathesis because it can be easily performed without anticoagulants. (C) 1998 by the Nation al Kidney Foundation, Inc.