Polymyxin BHigh cut off (HCO) membranes Cytokine binding therapies a b s t r a c t Continuous renal replacement therapies (CRRT) started as continuous arterio-venous hemodialysis (CAVH) 2 in the 1970s. Since then, the last 4 decades have seen numerous improvements in extracorporeal therapies. Some of the notable improvements have been the development of veno-venous therapies, the development of special low resistance filters with special geometry and fibers and improved machine safety with the use of microprocessors and sensors.Classic extracorporeal therapies have focused on the removal of small solutes for efficacy. However, it is well known that the characteristics of some solutes make their removal difficult. Also, limitations in efficiency of dialysis membranes, advances in hemadsorption and the development of newer filters have led to the application of extracorporeal therapies in the management of patients with multi-organ failure and sepsis, refractory congestive heart failure, acute neurologic injury, liver failure and patients with various other ailments.