Dialysis is a form of treatment that replicates many of the kidney’s functions.
Dialysis filters your blood to rid your body of harmful waste, extra salt, and water.
It's often used to treat advanced chronic kidney disease (kidney failure), where the kidneys have lost most or all of their ability to function.
Dialysis is an increasingly common type of treatment. In the UK, more than 40,000 people are affected by kidney failure, with more than half this number receiving dialysis.
Most people who need to have dialysis are over 65 years of age.
Why do I need dialysis?
If your kidneys stop working properly, waste products will build up and cause symptoms such as:
- itchy skin
- extreme tiredness (fatigue)
- swollen feet, hands and ankles
Without dialysis, kidney failure will eventually be fatal.
Read more about why dialysis is needed.
How long is dialysis needed?
Many people will need to have dialysis on a long-term basis (possibly for the rest of their lives). However, for a significant minority, the goal will be a kidney transplant.
Someone suitable for a kidney transplant will only need to be on dialysis until a donated kidney becomes available.
For someone who is not suitable for a kidney transplant, dialysis will be needed for the rest of their lives.
Types of dialysis
There are two types of dialysis – haemodialysis and peritoneal dialysis.
Haemodialysis is the type of dialysis that most people are aware of. It involves inserting a needle, which is attached by a tube to a dialysis machine, into a blood vessel.
Blood is transferred from your body into the machine, which filters out waste products and excess fluids. The filtered blood is then passed back into your body.
Most people require three sessions a week, each lasting four hours.
Peritoneal dialysis is a less well known type of dialysis, but it is becoming more common. It involves using the lining of the abdomen (the peritoneum) as a filter. Like the kidneys, the peritoneum contains thousands of tiny blood vessels, making it a useful filtering device.
During peritoneal dialysis, a small flexible tube called a catheter is attached to an incision in your abdomen. A special fluid called dialysis fluid is pumped into the space surrounding your peritoneum (the peritoneal cavity).
As blood moves through the peritoneum, waste products and excess fluid are moved from the blood and into the dialysis fluid. The dialysis fluid is then drained from the cavity.
The process of peritoneal dialysis lasts about 30-40 minutes and is usually repeated four times a day. Alternatively, you can run it overnight.
Which type of dialysis?
You may be able to choose which type of dialysis you want to use. However, in some situations a particular method of dialysis may be unsuitable – for example, if you have previously had major abdominal surgery.
There is usually no right or wrong answer when it comes to choosing between haemodialysis and peritoneal dialysis, and it is possible to change from one type of treatment to another. You can discuss this with your care team.
Both types of dialysis achieve similar results. However, in some situations a particular technique will be recommended.
For example, peritoneal dialysis is usually recommended for adults who are otherwise healthy apart from having kidney disease. Haemodialysis is usually recommended for older adults whose health is poor.
Both types of dialysis can be carried out at home, which means you do not have to visit hospital or a dialysis unit. Some people see this as an advantage, while others find the prospect daunting and prefer to have regular contact with staff at the hospital or dialysis unit.
Read more about the advantages and disadvantages of both types of dialysis.
There are different side effects for haemodialysis and peritoneal dialysis, but both types can make you feel exhausted.
Haemodialysis can also cause itchy skin and muscle cramps, while a common side effect of peritoneal dialysis is infection of the peritoneum with bacteria (peritonitis).
For people receiving haemodialysis, the risk of developing an infection is lower, but if it does occur it tends to be more serious.
Most major cities have dedicated dialysis units that can provide haemodialysis. There are also many smaller dialysis units based in hospitals and clinics across the UK.
Find a renal unit in your local area.
Dialysis is a potentially life-saving treatment for people who would otherwise experience significant disability, pain and eventually death. How successful the results of dialysis are depends on a number of factors.
Although dialysis is a demanding treatment that requires considerable personal discipline, many people achieve a good quality of life with some being able to continue in full- or part-time employment.
The average life expectancy of people who start dialysis in their late 20s is 20 years, while older adults aged over 75 on dialysis have an average life expectancy of four years. This should improve in the future. Some people have been on dialysis for more than 30 years.