{"id":3715,"date":"2019-05-30T11:13:45","date_gmt":"2019-05-30T10:13:45","guid":{"rendered":"https:\/\/kidneyresearchuk.org\/?page_id=3715"},"modified":"2025-06-23T12:06:18","modified_gmt":"2025-06-23T11:06:18","slug":"haemodialysis","status":"publish","type":"page","link":"https:\/\/www.kidneyresearchuk.org\/kidney-health-information\/living-with-kidney-disease\/care-and-treatments-for-people-with-kidney-failure\/haemodialysis\/","title":{"rendered":"Haemodialysis"},"content":{"rendered":"\r\n

What is haemodialysis?<\/h2>\r\n

Our kidneys usually filter and remove waste products and excess fluid from the blood. Haemodialysis is a way of replacing some of the functions of your kidney, if your kidneys have failed, by using a machine to filter and clean your blood.<\/p>\r\n

Blood is pumped out of your body to the machine where it is passed through a series of tiny tubes, in an ‘artificial kidney’ or ‘dialyser’. The tubes are made of a special membrane that allows waste products and fluid to pass across it. Clear fluid called ‘dialysate’ is passed outside the tubes in the opposite direction. As the blood passes in one direction and the dialysate in the other, waste products and excess water pass into the dialysate, which is then pumped out of the machine and the waste discarded down a drain, as your cleaned blood is pumped back into your body.<\/p>\r\n

Your blood passes continuously through the dialyser during each dialysis session. Dialysis sessions normally last around four hours and take place three times a week; longer sessions are required for bigger people and for people who tend to gain more fluid between dialysis sessions. Shorter sessions may be used for small people, people whose kidneys are still working a bit, and people who have treatment more than three times a week.<\/p>\r\n

Haemodialysis can be given in hospital, in free-standing dialysis units (often called satellite units), or at home. In hospital and satellite units, nurses and dialysis assistants help you with the treatment; home dialysis requires you or someone else to learn how to use the machine.<\/p>\r\n

You may feel tired after the dialysis session, but as haemodialysis only takes place up to three times each week, the intervening days can allow you a certain amount of freedom to do normal activities, although restrictions in diet and fluid intake are usually necessary.<\/p>\r\n

Haemodialysis machine<\/h3>\r\n

People are normally connected to the dialysis machine through two needles which are inserted into a ‘fistula’ or ‘graft’, usually in your arm. One needle takes your blood to the dialysis machine and the other needle brings back your cleaned blood.<\/p>\r\n

A fistula (‘arteriovenous fistula is the full term) is a larger and stronger blood vessel in your arm or leg to make it easier to transfer your blood to and from the dialysis machine. It is created by connecting an artery to a vein by a small surgical operation. This is usually done in the forearm, but may be in the upper arm, in which case the surgeon may do this in two stages.<\/p>\r\n

The fistula normally needs to be created around four to eight\u00a0weeks before haemodialysis begins to allow time for the vein to increase in size .<\/p>\r\n

If your blood vessels are too narrow you may be given an AV graft instead (where a piece of tubing is used to connect the artery to the vein). And sometimes, as a temporary measure or in an emergency, a small tube called a ‘catheter’,\u00a0 ‘neck line’, or ‘tunnelled line’ may be inserted into a vein in your neck or groin.<\/p>\r\n

How does haemodialysis work?<\/h3>\r\n

The thought of having needles inserted several times a week can be daunting. If you are concerned about this or scared of needles, an anaesthetic ointment can be applied instead a few hours before your dialysis session, or a local anaesthetic injection can be used to numb the area where the dialysis needles are inserted. The anaesthetic might ‘sting’ or ‘burn’ at first but this should only last a few seconds.<\/p>\r\n

Once both needles are inserted, special tubing is attached to them, which is then connected to the dialysis machine.<\/p>\r\n

You need to sit or lie down during your dialysis session but you can read, sleep or listen to the radio or watch programmes on your tablet or laptop \u00a0if you like. As you will be relatively still during the dialysis session, you may feel stiff at the end of the session.<\/p>\r\n

You won’t feel like your blood is draining from you because the process ensures that the amount of blood in the machine and tubing remains minimal. However, some people can feel dizzy, tired and sick during and after their session. And some people say it is uncomfortable having a fistula in their arm or leg.<\/p>\r\n

From time to time various blood tests are taken, and you may be asked to collect your urine to determine whether the frequency and duration of treatment are adequate and adjustments may be made on the basis of these measurements.<\/p>\r\n

Diet for haemodialysis patients<\/h3>\r\n

Most people on haemodialysis need to adjust their diet. The major change in diet is usually a reduction in foods high in potassium, phosphate and sodium (salt). But a kidney dietitian will work with you to create a plan which is tailor-made to your needs and lifestyle.<\/p>\r\n

One of the major restrictions that you may find difficult is your fluid intake, but reducing your salt intake may help you feel less thirsty. In the early stages of haemodialysis you may still pass some urine but, as time progresses the volume will decrease. In between dialysis sessions fluid tends to accumulate and if severe, shortness of breath can occur.<\/p>\r\n

Urine measurements will be made from time to time to assess your fluid allowance, and how much dialysis you need. When and if changes are required, your dietician or kidney nurse will discuss these with you.<\/p>\r\n

Medication and haemodialysis<\/h3>\r\n

Your kidney doctor may prescribe:<\/p>\r\n