dialysis

What is dialysis?

Dialysis is a procedure to remove waste products and excess fluid from the blood when the kidneys stop working properly.

It often involves diverting blood to a machine to be cleaned.

Who needs dialysis?

advanced chronic kidney disease (kidney failure), the kidneys may not be able to clean the blood properly. Waste products and fluid can build up to dangerous levels in your body.

Left untreated, this can cause a number of unpleasant symptoms and eventually be fatal. Dialysis filters out unwanted substances and fluids from the blood before this happens.

In many cases, you'll be able to choose which type of dialysis you want to have.

The two techniques are equally effective for most people, but each has its own advantages and drawbacks. For example:

Haemodialysis means you'll have four treatment-free days a week, but the treatment sessions last longer and you may need to visit hospital each time

Peritoneal dialysis can be done quite easily at home and can sometimes be done while you sleep, but it needs to be done every day

Both methods of dialysis are equally effective for most people, so it's usually a case of personal preference.

However, there may be some situations where a particular type of dialysis is best. For example, peritoneal dialysis may be recommended for:

• children aged two or younger
• people who still have some limited kidney function
• adults who don't have other serious health conditions, such as heart disease or cancer

Haemodialysis may be recommended for people who are unable to carry out peritoneal dialysis themselves, such as those who are visually impaired, have dementia or are in a poor state of health.

Most people need three sessions of haemodialysis a week, with each session lasting around four hours. This can be done in hospital, or at home if you've been trained to do it yourself.

Two thin needles will be inserted into your AV fistula or graft and taped into place. One needle will slowly remove blood and transfer it to a machine called a dialyser or dialysis machine.

The dialysis machine is made up of a series of membranes that act as filters and a special liquid called dialysate. The membranes filter waste products from your blood, which are passed into the dialysate fluid. The used dialysate fluid is pumped out of the dialyser and the filtered blood is passed back into your body through the second needle.

During your dialysis sessions, you will sit or lie on a couch, recliner or bed. You will be able to read, listen to music, use your mobile phone or sleep.

Haemodialysis isn't painful, but some people feel a bit sick and dizzy, and may have muscle cramps during the procedure. This is caused by the rapid changes in blood fluid levels that occur during the treatment.

At first, the bag containing dialysate fluid is attached to the catheter in your abdomen. This allows the fluid to flow into the peritoneal cavity, where it's left for a few hours.

While the dialysate fluid is in the peritoneal cavity, waste products and excess fluid in the blood passing through the lining of the cavity are drawn out of the blood and into the fluid.

A few hours later, the old fluid is drained into the waste bag. New fluid from a fresh bag is then passed into your peritoneal cavity to replace it, and left there until the next session. This process of exchanging the fluids is painless and usually takes about 30-40 minutes to complete.

Exchanging the fluids isn't painful, but you may find the sensation of filling your abdomen with fluid uncomfortable or strange at first. This should start to become less noticeable as you get used to it.

Most people who use CAPD need to repeat this around four times a day. Between treatment sessions, the bags are disconnected and the end of the catheter is sealed.