Techniques and Modalities of Continuous Renal Replacement Therapy

Abstract

In the last 40 years, continuous renal replacement therapy (CRRT) has evolved from an initial modification of maintenance dialysis to a fully integrated component of modern multi-organ support. In CRRT, solute removal is mainly accomplished through diffusion and convection. Current CRRT modalities include continuous veno-venous haemofiltration, continuous veno-venous haemodialysis, continuous veno-venous haemodiafiltration and slow continuous ultrafiltration. The main advantages of CRRT are improved metabolic stability and less fluctuations of osmotically active substances, better fluid management with avoidance of large fluid shifts and greater haemodynamic stability. CRRT is commonly combined with other forms of extracorporeal life support, including extracorporeal membrane oxygenation and CO2 removal, ventricular assist devices and liver assist techniques. Despite improvements in the design, safety and functionality of CRRT machines, adverse effects and shortcomings remain. Further advances in technology and improved collaboration between clinical teams and industry will be necessary to facilitate true personalized CRRT according to the needs of the individual patient. This paper reviews the physiologic principles behind the multifaceted aspects of CRRT and summarizes its role in clinical practice. In addition, remaining shortcomings and possible technological solutions are discussed to get closer to personalized CRRT.