Continuous treatment modalities in acute renal failure

Abstract

Continuous treatment modalities have become well established in the treatment of severely ill patients with acute renal failure since the introduction of continuous arteriovenous haemofiltration. However, this simple blood-pressure-driven treatment often fails to control azotaemia, especially in haemodynamically unstable patients with hypercatabolism. The common feature of further developments in continuous treatment modalities, such as continuous arteriovenous haemodialysis, venovenous haemofiltration, or venovenous haemodialysis is their higher efficacy in controlling azotaemia. Venovenous forms of treatment involve considerably higher technical requirements. The main advantages of continuous forms of treatment as opposed to intermittent haemodialysis are greater haemodynamic stability and the possibility of adapting nutrition without restriction to the needs of the critically ill. The uninterrupted necessity for anticoagulants is the most important disadvantage. The question of whether patients may profit from the continuous elimination of mediators involved in acute renal or multiple organ failure is still open. In retrospective analysis continuous methods appear to reduce mortality in acute renal failure, but prospective randomized studies are necessary to clearly demonstrate a benefit of these methods as opposed to intermittent haemodialysis.