Haemodialysis and Renal Failure

What is Dialysis?

Dialysis is a method of treating kidney failure. Natural waste products build up in the body and the kidneys are supposed to excrete many of these toxins in the urine. When the kidneys fail, the toxin levels build up. Dialysis helps to remove these toxins.

Dialysis works on the principle of diffusion. Toxins move from an area of high concentration (the sick patient's body) to an area of low toxin concentration (the fluid supplied in the dialysis process).

A fistula access is created surgically by connecting an artery to a vein to strengthen the vein in the forearm, or sometimes the leg


A special site, called an access, must be surgically created in the arm, leg or near the collarbone of the haemodialysis patient. The access is where the needles are placed to remove blood from the body and return it to the body after it is filtered by the dialysis machine. Three types of accesses exist: natural fistula, artificial grafts, and jugular vein catheters.


Haemodialysis removes waste and excess fluid from the blood when the kidneys cannot do so sufficiently. The blood is drawn intravenously, sent through a machine called a dialyser, and returned to the body through a blood vessel. Inside the dialyser, the blood is passed over a membrane that filters waste and fluid into a dialysate solution. The dialysate is then pumped out to a disposal tank and new dialysate is pumped in.

Continuous Ambulatory Peritoneal Dialysis (CAPD)

Continuous Ambulatory Peritoneal dialysis (CAPD) uses a natural filter, the peritoneal membrane. Unlike haemodialysis, the patient does not need to travel to a dialysis centre. Instead, patients are trained to do dialysis at home, on their own schedule

What is Renal Failure

Renal failure refers to the kidneys and their ability to function adequately. Renal failure is divided into two forms; acute and chronic.

Functions of the Kidneys

The kidneys are responsible for a wide range of functions:

What Causes Kidney Disease

Kidneys lose their ability to filtrate blood when damage to the nephrons has occurred. This damage may have been quick as a result of illness or injury or a gradual onset over years.

Diabetes and High blood pressure (hypertension) are the two most common causes of kidney disease.

Further Reading
  1. http://www.nlm.nih.gov/medlineplus/ency/article/003421.htm 
  2. http://www.renalinfo.com/us/how_kidneys_work_and_fail/kidney_functions/
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