Conventional Hemodialysis Versus Post-Dilution Hemofiltration in Incident RRT

Patients with chronic kidney disease (CKD) with criteria for renal replacement therapy (RRT) including uremic syndrome, have a stable state of hyperosmolarity due to urea despite not being an osmotically inactive ion. Also, these patients have alterations in urea transporters in the central nervous system (CNS) conferring a risk of neurological involvement due to an abrupt decrease in serum urea causing manifestations of the post-dialytic syndrome. Hemodialysis results in rapid removal of urea from the blood, much faster than the equilibrium rate between the brain and the bloodstream through the blood-brain barrier, resulting in an osmotic gradient that favors movement from water to the brain, causing cerebral edema, intracranial hypertension and dialysis-associated imbalance syndrome. Conventional hemodialysis (HD) uses diffusion and primarily decreases small solutes, while hemofiltration (HF) is based on convection that provides clearance mainly of medium-size molecules and small solutes with a slower rate of reduction.