Introduction to haemodialysis

What do my kidneys do?

The main role of normal kidneys is to get rid of waste products and water in the blood. They achieve this by filtering the blood and turning the waste into urine. They also produce certain hormones.

Making Urine

The kidneys filter the blood. In this way they get rid of waste products such as urea and creatinine and excess water from the body and therefore maintain a normal balance of water and salts in the body. They also remove excess acid made in the body.

Producing hormones

The second role of the kidneys is to produce a hormone called erythropoietin or EPO. This helps the body to make and maintain a normal level of red blood cells in the bloodstream.

The kidneys convert vitamin D into an active form that is important in maintaining a normal balance of calcium in the body and, as a result, keeping teeth and bones healthy.

The kidneys also play a role in maintaining normal blood pressure. Receptors in the kidney detect falls in blood pressure and causing the kidneys to release a hormone called renin which activates a series of chemical actions in the body leading to a rise in blood pressure.

What happens when my kidneys fail?

They stop making enough urine

They fail to remove excess waste products from the blood. These products are urea, creatinine, acid and excessive amounts of potassium. Waste products, such as urea and creatinine, build up in the blood and can reach toxic levels. The symptoms vary from person to person. Some people experience all the symptoms and some experience a few. Others will not suffer any symptoms at all, however, it is important to recognise that this does not mean that their kidneys are working. Symptoms include: lack of appetite, nausea, vomiting, metallic taste in the mouth, itching, drowsiness during the day, insomnia and restlessness at night, restless legs, leg cramps. These symptoms may also be caused by imbalances in the levels of salts such as potassium in the body.

They fail to remove enough excess water. This means that too much water stays in the body, this is known as ‘fluid overload’. Fluid overload causes swelling of the feet and ankles initially. In severe overload a patient may have shortness of breath. If overload is left untreated, it may put undue strain on the heart.

production of hormones is affected

The kidneys do not produce enough EPO in order to manufacture red blood cells. This causes anaemia and patients will experience symptoms according to the level of anaemia. Some of the symptoms are: lethargy, nausea, loss of appetite, lack of concentration, shortness of breath and feel the cold. The kidneys do not produce enough active vitamin D. This causes an imbalance between calcium and phosphate levels in the body resulting in weak and aching bones and itching.

Damage to the kidneys may cause them to overproduce renin leading to high blood pressure. This often causes headaches and if left untreated places the patient at higher risk of having a stroke.

Why do I need to have dialysis?

The only way to control the build up of excess fluid and waste products is to filter the blood using artificial means. This is called dialysis. The problems caused by the changes in production of hormones are not directly helped by dialysis but will require drug therapy, for example, EPO can be given by a regular injection, vitamin D by a tablet and any blood pressure problems can be addressed using tablets.

How do I decide what type of dialysis to have?

Once you have been told that you need long term dialysis because your kidneys are failing you will need to decide what is the best treatment for you. You will be given information about the two types of dialysis, haemodialysis and peritoneal dialysis, and the opportunity to discuss them with members of the dialysis team. Both types of dialysis provide a good treatment. Unless you have a medical problem that prevents you having a particular type of dialysis you will have a choice between them.

Generally, people make a decision based on the information they are given and how one or other treatment fits in best with their lifestyle.

What is haemodialysis? The basics

Haemodialysis is a word taken from Greek. It means literally ‘blood filtering’. Haemodialysis is a way of removing waste products from the bloodstream using an artificial filter in a machine. The blood is removed from the body by inserting two needles into a vein in the arm. The needles are attached to blood tubing on the dialysis machine. The blood comes out of the bottom needle, through the tubing, into the filter where it is cleaned. It comes out of the filter and is returned via the tubing into the top needle.

Because only a small amount of blood can be removed from the body at any one time, the blood needs to circulate through the filter many times before the waste products are removed. This takes, on average, four hours in order to bring the waste products in the blood down to an acceptable level.

When you start dialysis, your kidneys will not be functioning enough to keep the level of the waste products down and in a few days time they will have risen again. You will then need to have dialysis again. On average, you will need dialysis two or three times a week. It will not be less than twice a week and it is not usual for it to be more than three times a week.

Once you have started on dialysis, it will take a few months to settle down. You will be monitored during this time to see how well your dialysis is working. Depending on this, the number of hours and number of sessions a week will be tailored to suit your individual needs.

How am I attached to the dialysing machine?

As noted already, needles are placed into a vein immediately prior to dialysis and then removed immediately afterwards. Because our veins are not big enough for needles to be inserted regularly two or three times a week, a vein in the arm has to be made bigger. The vein is made bigger by performing a small operation on the wrist called a fistula. This will allow the nurses to insert the needles more easily.

The operation will be done as a day surgery outpatient, usually under local anaesthetic. It takes about six to eight weeks before the vein is ready to use after the operation. This operation can be performed well in advance of a patient needing dialysis. If you should need dialysis and the fistula has not been made or before the fistula is ready to use, you will be able to receive dialysis by way of a small catheter inserted into a large vein in the neck or shoulder. This is a temporary measure and will be removed when your fistula is ready to be used.

What can I do while I am on dialysis?

When you are dialysing, you will remain connected to the machine. You will be either sitting in a comfortable chair or lying on a bed and you will not be able to move from the bed or chair. However, there are activities you can carry out. Some patients chat, others watch TV, or read books and magazines. Others simply prefer to sleep. You may be able to drink and have a snack.

What will I feel when I am on dialysis?

During the dialysis you will not be aware of the blood circulating through the machine. However, there may be some problems that you will encounter whilst on dialysis which will effect the way you feel.

1. Low blood pressure

Sometimes, if fluid and waste products are removed too quickly from your blood, you may experience a drop in blood pressure. This could make you feel light headed, sweaty and sick. It is easily and quickly remedied by infusing fluid directly into the bloodstream through the machine or having a drink in order to replace the lost fluid.

2. Nausea

Nausea is sometimes experienced during and after dialysis because of changes in blood pressure.

3. Cramp

Cramp is sometimes experienced, usually in the legs. It is the result of rapid fluid loss or salt depletion. It can be remedied by replacing the fluid and salt.

4. Headaches

Headaches can occur towards the end of a dialysis session. They are the result of the removal of waste products and fluid.

These problems can be controlled if you follow your fluid, diet and medication instructions.

When and where will I have my dialysis?

Dialysis takes place in a special dialysis unit. There are several different units. You will be asked to attend a unit where there is available space and time for your sessions. This may not always be the nearest unit to you, however, you may transfer at a later date when a space becomes available.

Normally, there are two sessions a day, morning and afternoon, every day, Monday to Saturday. You will be asked to attend for either a morning or afternoon session depending on available times and days when you first start dialysis. These will be your regular times and days unless your treatment regime changes. If these are inconvenient for you, they may be changed as soon as another more convenient space is available.

How do I get to the dialysis unit?

Free transport can be arranged by your dialysis unit. This might be ambulance, car or taxi. This will take you both to and from dialysis. However, there may be some delays in returning home, if other dialysis patients are using the same transport. If you decide at anytime to make your own arrangements to be picked up from or dropped at the unit, you need to let the unit know in advance so that they may let ambulance control know.

You may drive yourself back and forth for treatment along as you are feeling well enough.

Can I learn to dialyse myself?

When you have unit based dialysis, the nurses take the responsibility for dialysis. However, there are a small proportion of patients who would like to learn to dialyse themselves at home. If you feel that you would like to do this you will need to discuss it with the unit staff. They will be able to advise you about dialysis at home. If you decide to go ahead, the nurses will train you to dialyse yourself. This training will take about three to six months depending on the individual. When you are confident that you know how to dialyse and the staff are also confident that you are able to dialyse safely then you will be able to have a machine at home.

Before this can happen, certain conditions have to be met. You would need to have facilities to dialyse at home, for example, a spare room or a garden big enough for a portakabin. You will also need someone to support you, a partner, spouse, relative or friend committed to being there for every dialysis session. They would not be trained to dialyse you, but would be trained to assist you should specific problems occur.

Haemodialysis at home offers more flexibility than unit based dialysis. Although the number of hours and sessions would be no different, you will be able to arrange your dialysis time to fit in with your lifestyle. However, this needs to be discussed between you and the person who will support you as haemodialysis at home can be stressful in the first few months.

Can I go away?

Yes, you can, whether you dialyse at home or in the unit.

If you want to go away just for the day on a special occasion and it coincides with your dialysis, let the unit know well in advance and they may be able to change your dialysis day for you.

If you want to go on holiday, you can, as long as there is a dialysis unit within travelling distance.

If you inform your local dialysis unit at least one month in advance of where and when you want to go on holiday they will be able to tell you if there is a dialysis unit near and, if there is, will book your dialysis for you. If there is no dialysis unit near, you will have to choose another holiday venue.

For holidays in the UK and Europe, the dialysis cost is met by the health authority, however, if you go outside the European Union, you will have to meet the dialysis cost yourself.

For a list of holiday dialysis venues/units please contact the National Kidney Federation, 6 Stanley Street, Worksop, Notts, S81 7HX, Tel: 01909 487795 or the British Kidney Patients Association, Bordon, Hants, GU35 9JZ, Tel: 01420 472021

Can I have a kidney transplant?

You may be suitable for a kidney transplant. If you are interested in this option then you will need to discuss it with your consultant. You may do this before you start on dialysis and at anytime after you have started dialysis. You will be referred to a transplant surgeon for an assessment in outpatients clinic. Routine tests will be arranged to see if you are medically suitable. If you are suitable, your name will be placed on a transplant waiting list and when a kidney which matches your blood group and tissue type becomes available you will be given it.

It is important to realise that the length of time you are on the waiting list depends on the availability of a suitable kidney and not how long you have been waiting.

Some people may have relatives who wish to make a kidney donation. In this case you will need to discuss it with your consultant and an assessment for you and your potential donor will be arranged.


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