[Anticoagulation in continuous renal replacement therapies (CRRT)].

Continuous renal replacement therapies (CRRT) are commonly used in the majority of critically ill patients who need dialysis. Treatment success depends on an efficient anticoagulation protocol devised to maintain the dialysis circuit unclotted, with minimal complications such as bleeding due to excessive anticoagulation. Several features can contribute to dialysis circuit thrombosis, such as the speed of pump blood flow, dialysis catheter, type of dialyzer membrane and also, the type of technique prescribed. Unfractioned heparin (UFH) is the anticoagulant most used in CRRT. Recently, low-molecular weight heparins (LMWH) have been shown to be safe and effective drugs for this purpose. In critically ill patients, who frequently have contraindications to systemic anticoagulation, regional anticoagulation with trisodium citrate is an increasingly accepted method due to its safety and efficiency if applied under strict metabolic control. Regional anticoagulation with UFH/protamin now has limited use because of side effects related to protamin. If the patient has contraindication to systemic anticoagulation or if regional anticoagulation with citrate is not available, continuous flushing of circuit dialysis with saline is the only applicable alternative. In patients with contraindication to heparinization, new drugs not yet available in Brazil, such as prostaglandins, recombinant hirudin, argatroban and nafamostat can be used.