Factors affecting hemodialysis and peritoneal dialysis efficiency

Hemodialysis and peritoneal dialysis are two blood purification techniques that use similar operating systems. The hemodialysis system is based on thr ee components (blood, membrane, and dialysate). The peritoneal dialysis sys tem is based on the same components that can, however, be less manipulated and adjusted. In hemodialysis the blood flow is the main determinant of sma ll solute removal thanks to a prevalently diffusive mechanism. Convection i s also used to transport larger solutes across the membrane, but this mecha nism relies on the high permeability coefficient of the membrane and high t ransmembrane pressure leading to high ultrafiltration rates. The membrane c an therefore influence the performance of the techniques as far as solute r emoval and ultrafiltration are concerned. Finally, diffusion is facilitated by an improved distribution of dialysate flow in the dialysate compartment . This can be achieved with a special dialysate pathway configuration based on space yams or micronodulation of the fibers. In peritoneal dialysis, bl ood flow and membrane characteristics can be less manipulated or almost not at all. The only variables are dialysate volume, flow, dwell time, and com position. Thanks to modification in these aspects of the dialysate, periton eal dialysis techniques with different clearances and ultrafiltration rates can be accomplished.