Dialysis is a form of treatment that replicates many of the kidney’s functions. It is often used to treat advanced chronic kidney disease, where the kidneys have lost most or all of their function. This is known as kidney failure or end stage renal disease.
The kidneys are two bean-shaped organs that are located at the back of the abdomen, behind the liver and intestines.
Every day the kidneys filter your blood, removing waste products collected as part of normal bodily functions, along with any excess fluid. The waste products and excess fluid become urine, which is stored in the bladder until you go to the toilet.
Why do I need dialysis?
If your kidneys stop working properly, waste products build up and cause symptoms including:
- itchy skin
- fatigue (extreme tiredness)
- blood in the urine (haematuria)
- swollen feet, hands and ankles
Without necessary treatment such as dialysis, kidney failure will eventually prove fatal.
How long is a person on dialysis?
Many people will remain on dialysis on a long-term basis (possibly for the rest of their lives) but for a significant minority the goal will be a kidney transplant.
A person who is a suitable candidate for a kidney donation only has to be on dialysis until a donated kidney becomes available. This can range from a few months for people who have a relative willing to provide a living donation, to around three years for people waiting for a deceased kidney donation to become available.
For people who are not suitable for a kidney transplant because of another serious health condition, such as cancer or severe heart disease, will need to be on dialysis for the rest of their lives. Often this is a safer option than a transplant.
Types of dialysis
There are two types of dialysis:
- 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's becoming more common. It involves using the peritoneum as a filter.
The peritoneum is a thin membrane that lines the inside of the abdomen and surrounds and supports the abdominal organs, such as the stomach and liver. Like the kidneys, the peritoneum contains thousands of tiny blood vessels, making it useful as a filtering device.
During peritoneal dialysis, a small flexible tube, known as a catheter, is attached to an incision in your abdomen. A special fluid called dialysis fluid is pumped into the space that surrounds your peritoneum (the peritoneal cavity).
As blood moves through the peritoneum, waste products and excess fluid are moved out of the blood and into the dialysis fluid. The dialysis fluid is then drained from the cavity.
The process of peritoneal dialysis lasts roughly 30 to 40 minutes and is repeated around four times a day. Alternatively, you can run it overnight.
Which type of dialysis?
In many instances the choice of which type of dialysis you use is up to you. However, there are some medical problems that can mean a method is unsuitable or less suitable (for example, a previous major operation on your abdomen).
There are usually no right or wrong answers 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 haemodialysis and peritoneal dialysis achieve similar results. However, there are some situations where a particular technique would 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 don't have to visit hospital or a dialysis unit. Some people feel that this is a big advantage while others find the prospect daunting and prefer the regular contact they have with staff at the dialysis unit or at hospital.
Read more about the advantages and disadvantages of both types of dialysis.
There are different side effects for haemodialysis and peritoneal dialysis but they can both 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, known as peritonitis.
People receiving haemodialysis have a smaller risk of contracting infection, but if it does occur, it tends to be more serious.
Who uses dialysis?
Dialysis is a relatively common type of treatment. Each year, in England, around 5,500 people experience kidney failure and there are currently around 41,000 people receiving treatment for kidney failure. Of those affected:
- around half are treated with a kidney transplant
- around 4 out of 10 are treated with haemodialysis
- around 1 out of 10 are treated with peritoneal dialysis
Most people who have dialysis are over 65 years of age.
Most major cities have dedicated dialysis units that can provide haemodialysis. There are also many smaller dialysis units based in hospitals and clinics across England. You can find a renal unit near you using our service search.
Dialysis is a potentially life-saving treatment for people who would otherwise experience significant disability, pain and eventually death. However, how successful the results of dialysis are depends on a number of factors.
Although dialysis is a demanding treatment, which requires considerable personal discipline, many patients achieve a good quality of life and some carry on in full or part-time employment.
In the past, people on dialysis did have a limited life expectancy. However, due to advancements in treatment the average life expectancy of people on dialysis has increased and is expected to continue to increase in the future.
The average life expectancy of younger people who are in their twenties is 20 years and this should improve in the future. Some people have been on dialysis for more than 30 years.