Dialysis

What is dialysis?

There are two types of dialysis - namely haemodialysis and peritoneal dialysis. Please note though - within each type - there are two versions of each form of dialysis. In some cases though - people who have kidney failure may choose not to have dialysis treatment, this is often known as Conservative Care.

Haemodialysis

Blood is taken from the body to be cleaned in a filter known as a dialyser (artificial kidney). A dialyser works on the principle of blood flowing along one side of a semi-permeable membrane made of cellulose or a similar product, with fluid which is known as dialysate flowing along the other side. The dialysate fluid contains a regulated amount of minerals normally present in the blood in safe levels. In kidney failure they are present in excess. The membrane has tiny holes of different sizes so that the excess fluid and substances which are at high levels in the blood pass through to the dialysate and this effectively cleans the blood. This happens at different rates, small molecules such as potassium are removed quickly and larger ones more slowly, until the blood levels of the toxic waste products from the body are at a safe level.

A haemodialysis machine regulates how fast the blood flows, at what pressure and how quickly the exchange happens.

As only a very small amount of blood is in the dialyser at any given time, blood needs to circulate round from patient to dialyser to patient again for around 4 hours. Treatment is usually 3 times per week. This is known as your dialysis dose and is decided by your Renal Consultant working closely with your dialysis nurses for each patient in a prescription. This is known as IN-CENTRE HAEMODIALYSIS TREATMENT (ICHD) – This is available at 3 Hospitals if your care is under UHNM – namely Royal Stoke (the main ICHD unit), along with County Hospital at Stafford and also the Crewe unit at Leighton Hospital (these are the 2 satellite units)

This type of dialysis needs access to the blood stream. Blood is carried from the patient to the dialyser and returned through dialysis lines (plastic tubes) which are connected to the patient in one of two ways explained below.

Fistula

The joining of a vein and artery just under the skin, usually on the forearm makes the vein swell to allow needles to be inserted and removed after each treatment. Between treatments only a small scar and swelling are visible.

Central Venous Catheter

A soft plastic tube is inserted in a large vein, either in the side of the neck or, less often, into the top of the leg and comes out further down on the chest wall or top of the leg after passing underneath the skin.

Home Dialysis

Patients may also be able to perform haemodialysis from the comfort of their own respective home – this is called Home Haemodialysis (HHD)

Peritoneal Dialysis

Peritoneal dialysis (PD) is one of the two types of dialysis (removal of waste and excess water from the blood) that is used to treat people with kidney failure.

In PD, the process of dialysis takes place inside the body. The abdomen (tummy) has a lining called the peritoneal membrane, which can be used as a filter to remove excess waste and water. A tube (catheter) is inserted into the abdomen during an operation. Special dialysis fluid is drained into the abdomen. Excess waste and water pass from the blood into the fluid and after a few hours the fluid is drained out.

Can anyone do PD?

PD is a suitable treatment for most people with end stage renal failure (ESRF). People who have had several major abdominal operations may not be able to have PD. People who are blind or have problems with their fingers such as arthritis can usually do PD, with the help of a special system and devices.

PD requires a lot of commitment from kidney patients and their families. People on PD are usually responsible for their own dialysis, in their own homes. For this reason, PD may not be suitable for some people who have no support at home.

Elderly people, living in Nursing Homes can sometimes get help to carry out their PD. We are extremely fortunate at UHNM to be able to offer an Assisted APD service through a team of dedicated nurses.

The renal team will be able to speak with you about this in detail if this is of interest to you or a family member who is a patient.

Are there different types of PD?

There are two main types of PD. The most commonly used type is known as Continuous Ambulatory Peritoneal Dialysis (CAPD). In this form of PD, patients have fluid in their abdomen 24 hours a day. At the end of each period of dialysis, they have to change the dialysis fluid themselves.

The other type is known as Automated Peritoneal Dialysis (APD). ‘Automated’ means that a machine changes the dialysis fluid for the person, usually at night.