Continuous Renal Replacement Therapies (CRRT) Overview

The continuous renal replacement therapies (CRRT) are extracorporeal treatments for kidney failure provided to critically ill patients. Initially developed as arteriovenous therapies, CRRT is now provided primarily as pump-driven venovenous treatments. The modalities of CRRT include slow continuous ultrafiltration (SCUF), which is used for the management of volume overload, primarily in patients with decompensated heart failure; continuous hemofiltration (CAVH or CVVH), in which solute removal occurs primarily through convective transport; continuous hemodialysis (CAVHD or CVVHD), in which solute removal occurs primarily by diffusion; and continuous hemodiafiltration (CAVHDF or CVVHDF), which combines the convective transport of continuous hemofiltration with the diffuse solute transport of continuous dialysis. This chapter reviews the basic principles of these modalities of therapy, including the necessary components of a CRRT circuit, the composition of dialysate and replacement fluids, and anticoagulation.