Evolution of Vascular Access and Anticoagulation.

Abstract

Continuous renal replacement therapy (CRRT) is an important and widely used adjuvant treatment in critically ill patients. However, any CRRT protocol can be adhered to only when the technique is correctly installed and functioning properly. Within this context, an appropriate vascular access and a safe and effective circuit anticoagulation method are key requisites. The right internal jugular (RIJ) vein is the preferred route for insertion with the tip of the catheter placed in the right atrium. Both femoral veins offer a valuable alternative access, but catheters must be longer to avoid recirculation and circuit blood flow is lower as compared with that of the RIJ approach. The location of the catheter is not associated with differences in bacterial colonization/infection rate or filter/circuit lifespan. Adequate anticoagulation is imperative to avoid a system "shutdown" due to the early clotting of the filter. For a long time, unfractionated heparin (UFH) was the anticoagulant of choice. UFH is associated with an increased bleeding risk and requires the use of high circuit blood flows. The introduction of regional citrate anticoagulation (RCA) created a paradigm change in CRRT anticoagulation. RCA can be applied safely in patients with increased bleeding risk and may enhance filter and circuit survival as compared with UFH. RCA requires close monitoring for potentially serious metabolic side effects. Future perspectives include improved catheter technology and development of novel citrate solutions with less severe metabolic impact.