Haemodialysis: general information

Haemodialysis is a physical replacement of kidney function for patients with critically reduced kidney function (uraemia), the most severe stage of chronic kidney failure. The treatment replaces the four main kidney functions:

Removal of toxic substances

of electrolyte equilibrium

Restoration of acid-base equilibrium

of fluids

The first two functions are performed by subjecting the patient’s blood (“hemo”) to the physical principle of dialysis: the blood flows through a filter, where it comes in contact with a biocompatible semi-permeable membrane which retains only (or at least in greater quantity) the toxic substances that that need to be removed.
In addition to the removal of toxic substances, the filter allows for the reintegration of alkaline radicals and the subsequent restoration of acid-base equilibrium.

The last function is related to the removal of the liquid intake that is not eliminated by urination, when urination is extremely reduced or absent (anuria) in end-stage nephropathy patients. The method used is ultrafiltration.

There are separate groups of dialysis techniques:


The blood is extracted from the patient,
introduced into an extracorporeal circuit, filtered through
the semi-permeable membrane and reinfused.

Peritoneal Dialysis

The blood is filtered inside the patient’s body through a peritoneal membrane covering the inner walls of the abdomen and the abdominal organs. The dialysis solution is introduced into the abdominal cavity and then removed through a small tube called peritoneal catheter. This treatment is done daily and can be performed at home.