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Dialysis treatment with the 5008 therapy system.

Almost 4.7 million people are treated because of suffering from chronic kidney failure around the world. The kidneys of these patients are unable to filter metabolic toxins and excess water from the blood for excretion through the urine. About 3.8 million patients rely on regular, life-saving dialysis treatment – either at a dialysis clinic or at home – to prevent the damage of further organs these toxins can cause when they accumulate in the blood.

When the kidneys fail, the whole body suffers. As the organs’ ability to filter the blood begins to fail, an excessive amount of protein is often excreted through the urine. The body then lacks this protein. In addition, edemas (retained water) can form in the legs or lungs. In many cases, an insufficient amount of toxins is also removed. These then collect in the blood and can damage other organs. Problems in the digestive tract can appear and even lead to bleeding ulcers. The toxins can even disturb the rhythm of the heart or lead to infection in the pericardium (heart sac). Nervous system disorders have also been observed.

According to estimates, the number of people worldwide suffering from chronic kidney failure and requiring dialysis treatment is rising at a rate of around six percent each year. This is primarily due to a longer life span, which increases the chance of kidney disease. In addition, the treatment of kidney patients in many developing countries is improving. The constantly increasing rates of high blood pressure and diabetes – the main causes of chronic kidney failure – also play a role.

What the kidneys do

The human kidney is a small biological miracle with an intriguing design and function. It plays a vital role in the body since it is a significant part of the metabolic process. Kidneys come in pairs and are each about eleven centimeters long in an adult and weigh an average of 160 grams.

Kidney functions

Kidneys remove excess water and detoxify the body

The kidneys create urine, which is excreted through the urinary tract. The urine is also used to remove excess water from the body as well as many toxins. The organs also regulate the acid-base balance in the body, preventing the acidification of the blood.



Kidneys control vital bodily functions

Kidneys also play a key role in the regulation of blood pressure. This is controlled by various hormones that are produced in the kidneys. Another hormone produced by these organs is Erythropoietin, which controls the production of red blood cells in the bone marrow. In addition, the kidneys also adjust calcium levels and play an important part in the production of vitamin D, which contributes to strong bones.

Types of dialysis

The basic differences between the two types of dialysis treatment are as follows:

  • Hemodialysis accounts for about 89 percent of all dialysis therapies. In hemodialysis, blood is filtered outside the patient’s body using an artificial kidney (dialyzer). The patient’s circulation is monitored and controlled by a dialysis machine.
  • In peritoneal dialysis, the lining of the abdominal wall, known as the peritoneum, is used as a natural filter for dialysis. This type of dialysis is typically performed by the patients at home and was used by about 390,000 patients at the end of 2019.


A kidney transplant is the third treatment option for patients with chronic kidney failure. However, there is a very limited supply of donor organs. More than 815,000 renal patients around the world live with a donor kidney.

Modern technology replaces vital kidney functions

Most patients with chronic renal failure receive treatment at a dialysis clinic three to four times a week – either in a dialysis clinic or at home. Modern technology replaces vital kidney functions during treatment. A dialysis machine pumps blood from a special vascular access in the lower arm of the patient into a dialyzer, the so-called artificial kidney. The dialyzer filters metabolic waste products and removes excess water from the blood. These waste products are then flushed out with dialysis solution and the filtered blood is returned to the patient’s body.

While the blood is cleaned inside the dialyzer, the dialysis machine monitors the circulation of blood outside the body and controls the composition of the dialysis fluid. Furthermore, it pumps blood and dialysis solution through the dialyzer in two separate circuits. Anti-coagulants are also added to the blood to prevent it from clotting.

The lining of the abdomen is used as a dialysis membrane in peritoneal dialysis


In peritoneal dialysis, the lining of a patient’s abdominal cavity – the peritoneum – acts as the filter for the blood. The peritoneal cavity stores the dialysis fluid and the filtration takes place across the peritoneum. Toxins and excess fluid cross the peritoneal membrane during the treatment and are thereby removed from the body.

A permanent tube, or catheter, that was inserted into the peritoneal cavity is used to introduce the dialysis fluid into the abdominal cavity. The dialysis fluid is fed into the cavity and left to absorb the impurities from the blood. Later, the fluid is drained-off into a bag and replaced with fresh fluid. This process, of filling and draining, can be done manually during the day or automatically over night with a cycler.

Dialysis products

Fresenius Medical Care offers a comprehensive range of products for hemo and peritoneal dialysis, covering all aspects of dialysis treatment.

About half of all dialysis machines and dialyzers sold each year are produced by Fresenius Medical Care.


In hemodialysis, the dialyzer acts as an artificial kidney and replaces vital functions of the natural organ. Blood flows through as many as 20,000 extremely fine fibers, known as capillaries, clustered in a plastic tube approximately 30 centimeters long. The capillaries are made of Fresenius Polysulfone, a special plastic with exceptional filtering and hemocompatibility characteristics. Pores in the capillaries filter metabolic toxins and excess water from the blood and flush them out of the body with dialysis fluid. Blood cells and vital proteins remain in the blood. Dialyzers are used only once in most industrialized countries.

Almost half of all dialyzers in use worldwide come from Fresenius Medical Care's production sites.

The computer-controlled dialysis machine is one of the most important products in the treatment of chronic renal patients and, in hemodialysis, it takes over a number of key functions – it pumps blood from the patient’s body through the blood lines to the dialyzer (artificial kidney or filter). There, a fluid known as dialysate transports the toxins and excess water filtered from the blood away from the body. The fluid is introduced against the flow of blood through a separate circuit that is also controlled by the dialysis machine. In addition, the device injects drugs (such as Heparin) that restrain coagulation. The system has a number of automatic monitoring and control functions that ensure a safe and efficient dialysis treatment for patients.

More than half of all dialysis machines worldwide come from Fresenius Medical Care's production sites.

There are two types of peritoneal dialysis: Continuous Ambulatory Peritoneal Dialysis (CAPD) and Automated Peritoneal Dialysis (APD).

In CAPD, the treatments are performed continuously without a machine. Typically, three to five exchanges are done per day in a clean environment – at home, at work or while travelling. In Automated Peritoneal Dialysis (APD), a dialysis machine (cycler) takes over the exchange of fluid, making overnight treatment possible. Most patients carry out both types of treatment themselves, either at home or in the office. This allows them to be flexible and to maintain their normal rhythm of life.

Dialysis may perform most of the kidneys’ vital functions but it can not entirely replace the natural organ. For this reason, patients with chronic kidney failure must also take drugs to control e.g. the balance of minerals in the body and prevent a lack of red blood cells (anemia). Fresenius Medical Care produces and markets selected medications for the treatment of chronic renal patients and will continue to expand its product portfolio.

Dialysis services

The wide majority of hemodialysis patients undergo out-patient treatment at one of about 45,600 dialysis centers around the world. The blood-filtering therapy is usually administered three times a week and lasts three to five hours per treatment. When patients are not receiving treatment, they lead largely normal lives.

Home dialysis (Peritoneal dialysis or home hemodialysis) is an alternative to treatment at a dialysis clinic. Working patients especially benefit from home dialysis since it offers more flexibility.

Fresenius Medical Care itself operates more than 4,100 dialysis centers around the world and bases its dialysis treatment on high quality standards. Experienced doctors and well-trained personnel care for the patients. The goal is to use innovative therapy concepts and modern technology from Fresenius Medical Care to ensure the best-possible quality of life for chronic kidney patients.

Peritoneal dialysis is a relatively simple and very effective home dialysis technique. As such, it has been successfully developed as the preferred method for home dialysis.

Also, hemodialysis treatment can be done by the patients on their own and in the comfort of their own home. Home hemodialysis allows patients to dialyze more frequently but for shorter periods than in a dialysis clinic. This may bring improved treatment results. It is also possible to carry out home hemodialysis overnight (nocturnal hemodialysis), while the patient sleeps.


Fresenius Medical Care AG & Co. KGaA
Else-Kroener-Strasse 1
61352 Bad Homburg
T: +49 6172 609-0


Explanatory video: How does Dialysis work?

When kidneys fail, dialysis takes over and performs their most important functions.