On the one hand, you can take the phrase ‘kidney replacement’ literally: some people do actually receive, via transplantation, a new, well-functioning kidney.

More often, sometimes only temporarily while a person waits for a suitable organ to be found, kidney replacement means dialysis. This process removes toxins and excess water from the blood. Two different types of dialysis are relevant: peritoneal and haemodialysis.

Peritoneal Dialysis

In peritoneal dialysis, the lining of the patient’s own abdominal wall is used as the filter. Clean dialysis fluid is passed into the abdominal cavity through a narrow tube or catheter that is permanently fixed in the abdominal wall during a surgical procedure.

Toxic substances and excess water gradually, over several hours, pass from the blood into this dialysis fluid. Once these waste products have accumulated in the dialysis fluid, this can be removed via the catheter and replaced with clean fluid. Such a procedure needs to be performed three or four times a day, each time for half an hour.

Overnight the dialysis fluid can stay longer in the abdomen. This type of peritoneal dialysis is called CAPD (continuous ambulatory peritoneal dialysis). An alternative is APD (automatic peritoneal dialysis), in which abdominal dialysis is performed only overnight by a machine operating automatically.

This has the advantage that you are not hindered during the day. Peritoneal dialysis has both advantages and disadvantages. The main advantage is that you remain mobile. You can undergo dialysis by yourself at home, at work, on holiday, on long journeys or even in an aero-plane.

Obviously, it is essential to have proper education and training by a specialized care team. Travel domestically and abroad is possible, without particular problems. You just have to ensure that sufficient supplies of key materials, especially the dialysis fluid, are available or send them ahead.

A good dialysis centre will usually have addresses and contact details for dialysis centers near your holiday resort. Problems may arise with peritoneal dialysis through infection and inflammation of the abdominal wall or at the site of insertion of the catheter. It is important to recognize such problems early and report them to a doctor immediately.

Most infections can be treated at home with antibiotics. If there are no particular problems, it is sufficient for a patient on peritoneal dialysis to visit the dialysis centre only once a month, to have the blood parameters and general health checked.

Is peritoneal dialysis suitable for you? There are several illnesses that are not compatible with peritoneal dialysis. These include seriously overstretched lungs, because the fluid in the abdominal cavity can hamper breathing. In addition, patients who have suffered ruptures, for example to the stomach wall, or have scars in their abdominal cavity from operations or who have intestinal disease are not suited to this type of dialysis.

Haemodialysis

During haemodialysis, the toxins and excess water are removed from the blood through a filter that is outside the body, inside a dialysis machine. The blood is pumped into the machine from a large vein, purified there, then returned to the body.

For haemodialysis to be possible over a long period, a good entry point to the circulation must be maintained. Veins all have very soft walls which would give way and close themselves if you tried to keep them permanently open for dialysis. Therefore, a small operation is performed to create an artificial opening.

For this, a vein in the wrist is usually linked to an artery, creating a shunt. The blood, which is under high pressure in the artery, then flows directly into the vein and widens it. In this way, sufficient blood flow for the dialysis is ensured. In the machine, the blood is purified over a filter.

Toxins and excess water pass across the filter membrane into the dialysis fluid and are thus removed from the body. The dialysis is usually performed three times a week for 4–6 hours. The patient either travels to a dialysis centre or has a machine at home for his or her own use. Haemodialysis patients may also travel, because there are dialysis centers in major towns in all countries, where you can make an appointment in advance.

What To Look Out For

People with diabetes often have hard vessels in their arms. It is therefore important that a shunt is created early, perhaps even months before dialysis is started. This allows the vessel entry point to establish itself firmly. Dialysis patients are taught to take care of the vessel entry point.

If it is necessary to draw blood, this should be taken from the other arm; the blood pressure should also be measured only in the other arm. When gardening or exercising, it is important to make sure that no pressure is exerted on the shunt and that it is not damaged.

Two main problems may arise with the blood entry point: clots may form or it may become infected. The blood flow in the region of the shunt must be checked daily. The patient can do this by probing the shunt: if the blood flow is good, a buzz will be felt. You can also listen to the blood flow using a stethoscope.

Skin infections can result from wounds or scratching with the fingernails. Thorough cleaning is therefore essential. Every patch of redness or dampness or other sign of infection should be reported to your doctor as quickly as possible.

Transplantation

Today, kidney transplantation, eventually combined with transplantation of a pancreas or just islet cells, is undoubtedly the best form of kidney replacement therapy. The new kidney is usually implanted in the pelvic region; the pancreas may be put into the pelvis or the abdomen.

One problem when an entire pancreas is transplanted is that this organ produces not just insulin and other hormones but also pancreatic enzymes that are usually secreted into the intestine. With a newly transplanted pancreas, these enzymes have to be directed into the intestine or the bladder.

A combined kidney and pancreas transplant is relatively rare: about 700–800 such operations are performed worldwide each year, almost exclusively in people with Type 1 diabetes. If it is successful, the patient is relieved of the need for dialysis and his or her diabetes is also cured, so that there is no longer a need to inject insulin.

The success of combined kidney and pancreas transplants has improved over the last 10 years. In the first year after transplantation, about 80–85% of patients are insulin-independent; this falls to about 63–75% of patients after five years. The life expectancy is much better after a transplant than on dialysis.

However, the recipients do have to take immunosuppressant drugs for the rest of their lives to prevent rejection of the new organs. There is currently much less experience with the transplantation of islet cells than with an entire pancreas.

In principle, this is the ideal procedure, because only the islet cells that make the insulin – the socalled beta cells – are transplanted. The advantage is that there is no extra production of digestive enzymes. In addition, the method is very simple because the isolated islet cells can be injected into the hepatic vein.

They attach there and grow, making insulin that passes directly into the circulation, where it is needed. Unfortunately, the long-term results with this procedure are not yet very good. The islet cells are often destroyed again and the insulin produced by them is often not sufficient to cure the diabetes, so that the patient has to continue to inject insulin.

There is a promising new development. In Canada, they have succeeded in preventing the rejection of the islet cells with new immunosuppressant drugs and thereby greatly improved the outcome of islet cell transplantation. This method is being tested in studies worldwide.

A transplant is not suitable for everyone. Intensive tests are required to see who has a good chance of successfully coming through such major surgery. People who suffer from other accompanying diseases, and in whom the heart may be damaged, may not withstand the stress of the operation and the consequent suppression of the body’s defense system, the immune system.

Which form of kidney replacement therapy is best for an individual must be considered very carefully, in consultation with the nephrologist, the surgeon and the diabetologist.