[Citrate: a different mental approach to extracorporeal circuit anticoagulation]

Citrate anticoagulation (RCA) during continuous renal replacement therapy (CRRT) in intensive care units (ICUs) is a practical application of a regional technique in which anticoagulation is virtually restrained to the extracorporeal circuit. This technique involves a different mental approach to anticoagulation, which gives RCA an advantage over systemic anticoagulation. The efficacy of anticoagulation depends on the level of citratemia reached in the circuit (from 2 to 6 mmol/L) and the associated decrease in ionized calcium (from 0.5 to 0.1 mmol/L). Compared with heparin in ICU patients in terms of efficacy and safety, citrate is able to maintain circuit patency for the same time, if not longer. It also reduces the risk of bleeding and the need for blood transfusions. Metabolic alterations during RCA such as metabolic alkalosis, hypocalcemia and hypernatremia are rare and of little clinical impact; their incidence is similar to those reported during CRRT with heparin. In patients at risk of citrate accumulation due to liver metabolism failure, the citrate load returning to the patient can be reduced by increasing the dialysis effluent volume. The popularity of RCA worldwide is neither high nor uniform. Apart from clinical indications, its diffusion is influenced by local and logistic conditions, the level of staff skill, and economic factors. However, thanks to the availability of dedicated monitors, disposable materials, and easy-to-learn operative protocols fitting patients' needs the use of RCA is increasing. For these reasons, RCA is expected to become the ruling anticoagulation approach during CRRT in ICUs.