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HAEMODIALYSIS - DIALYSIS - ARTIFICIAL KIDNEY

Why is Haemodialysis performed ?

In patients with severe acute or chronic renal failure failure, waste products accumulate, making them feel ill. Dialysis is needed in such patients to remove the waste products from the blood. For some patients, haemodialysis is the best approach.

Preparations needed for Haemodialysis

To get blood from the body to the dialysis machine, access is needed to your arteries and veins. There are three types of access: a fistula is the commonest form of access. It is usually produced in the wrist by connecting an artery to a vein. This is done by a small operation and you will be able to go home the next day. As the fast-flowing blood enters the vein, the vein grows gradually larger. Needles needed for the tube connections can then be placed into it. It takes 4 to 8 weeks for the fistula to grow large enough to be used for dialysis. Two needles can then be inserted, one to take the blood to the machine and the other to return the blood. Local anaesthetic is used before the needles are put in. They are removed again after dialysis. It is possible to have baths and go swimming with a fistula. To get immediate access to the blood supply, a soft plastic tube, or catheter, in the neck can be used. This is called a neck line . The catheter is placed by the doctor into a large vein (jugular or subclavian) in the neck. For this procedure, you must lie flat. The doctor will then give a lot of local anaesthetic before putting in the catheter. The catheter is covered up and taped down after each dialysis. This kind of access is only temporary. By tunnelling the catheter under the skin, the catheter can last for many months without needing to be replaced. This is called a Permcath.

What Happens during Haemodialysis

Haemodialysis is a way of clearing the blood of waste substances with an artificial kidney or dilysis machine. Your blood will be led through tubing to the inside of the artificial kidney. Here, there are membranes containing many tiny holes or pores. Harmful waste products and excess water pass through the pores to the other side of the membrane into clear fluid called dialysate. This fluid is pumped through the artificial kidney, and out into a drain. Blood which has now been cleared of its waste products is led by tubing back into your blood circulation. As only a small amount of blood is out of the body at a given time, it takes four to five hours to « clean » the blood. Haemodialysis is usually needed three times a week.

Possible Complications during Haemodialysis

Although most patients have no discomfort on dialysis, some will feel sick. If you have gained a lot of weight between dialyses due to fluid retention, this fluid will have to be removed during the dialysis. If this is done too quickly, the blood pressure will drop and you may feel faint. This problem is worse in patients who have a heart condition as well. Problems with access can also occur; fistulas or Permcaths may clot. A neck line can then be inserted for immediate access, but another fistula at a different site will have to be made. Because haemodialysis is only carried out three times a week, patients need to be careful with their diet. Foods with potassium and phosphate are limited and fluids are restricted. Although haemodialysis cleans the blood, it is not as efficient as a pair of normal kidneys. You are therefore likely to experience many of the problems of patients with kidney failure anaemia, pain in the bones, fluid overload and high blood pressure. You will also be more likely to pick up an infection, and if you are a little older, you may also get a heart attack or stroke. Patients who have been on dialysis for 15 years or more may develop joint problems. The anaemia of dialysis patients can now be treated by a drug called erythropoietin (EPO); this is best given by subcutaneous injections.

If Haemodialysis is not performed

If normally on regular treatment, delay in having a dialysis will result in you feeling very unwell. If no treatment at all were carried out, serious illness would result, with eventual coma.

Effects on Family of Haemodialysis

If you have a kidney machine at home, you will need help during dialysis. Family also will need to support you with diet and fluid restriction. If having your dialyses in hospital, then family or friends may need to help with the transport.