Basic Principles of Hemodialysis

Abstract

Chronic hemodialysis replaces the excretory functions and the water and electrolyte homeostasis functions performed by the healthy kidney. This is achieved by a discontinuous exchange of water and solutes across a semipermeable membrane, separating the patient’s blood from the dialysate fluid, whose composition is close to that of normal extracellular fluid. A hydrostatic pressure gradient may be created between the blood and the dialysate to remove by ultrafiltration the excess water and salt accumulated between dialysis sessions²⁵.