Continuous renal replacement therapy: opinions and evidence

Continuous arteriovenous haemofiltration (CAVH) is the first example of continuous renal replacement therapy (CRRT). CAVH was first applied for the treatment of diuretic unresponsive fluid overload. Subsequently, CRRT has undergone a remarkable growth, and it is now performed with pump technology (CVVH) and via double-lumen central venous catheters. In many intensive care units, especially in Australia and in Europe, CRRT has become the dominant, if not exclusive, form of artificial renal support. Continuous haemofiltration is now used beyond the original indications of blood purification, for the treatment of certain drug intoxications, for severe cardiac failure, for volume control during, after cardiopulmonary bypass, and to decrease the toxicity of chemotherapy. Furthermore, there is strong ongoing research into its role or that of derived techniques as possible adjuvant therapies during severe sepsis. Despite its large use, the current state of CRRT is surrounded by some controversies, and an effort should be made to give a dispassionate distillation of the literature for a final common definition of what is based on opinions and what carries sufficient evidence.