What are the Different Types of Dialysis?

In Germany, hemodialysis (HD) predominates with 86.1%. In this process, an “artificial kidney“(= hemodialyzer) is connected directly to the bloodstream. Although it bears no visual resemblance to real kidneys, it can mimic their function within certain limits. However, its detoxification capacity does not correspond to more than 10-15% of healthy kidneys.
The hemodialyzer consists of a system of several plastic membranes, past which the blood, rendered uncoagulable, is passed by means of a pump. On the other side of the membrane there is a salt solution into which the waste products pass due to the difference in concentration. In addition, water is pressed out (“ultrafiltration”). A machine monitors the exact procedure, functions, temperature, blood pressure and other parameters. The procedure takes 3-5 hours and requires about 120 l of water.

What is a shunt?

As toxins gradually accumulate back into the blood, the treatment must be performed about 3 times a week. Since this requires regular access to the patient’s blood system, the patient is given a so-called shunt – a permanent connection between an artery and vein, usually on the forearm, which causes the vein to dilate considerably and can therefore be easily punctured.

The treatment is usually performed in special dialysis centers, but is also possible as home dialysis. Relatively common side effects of HD are circulatory problems with a drop in blood pressure and nausea, muscle cramps and cardiac arrhythmias, as well as infections and occlusions of the shunt.

Hemofiltration (HF)

In this form, waste products do not pass through the membrane passively but are actively forced through. The removed fluid is replaced with an infusion solution. HF is used in only 0.1% to 1.3% of cases.

Hemodiafiltration (HDF).

As the name suggests, this procedure is a combination of the two procedures mentioned above. It is used – depending on the state – between 5% and 24%.

Peritoneal dialysis (PD).

This procedure takes advantage of the semipermeable properties of the peritoneum and vascular walls. A permanently positioned plastic catheter is implanted in the patient, through which sterile irrigation fluid is introduced into the peritoneal cavity 4 to 6 times daily, left there for 5 to 8 hours, and then drained. The toxins from the blood migrate through the peritoneum into there and can be removed.

The procedure can be performed in various modifications and with additional equipment, and it can be performed by the patient. This has the advantage of independence and flexibility, more even concentration of toxins in the blood and less strict dietary requirements. This makes PD particularly suitable for children. The disadvantage is that there is an increased risk of peritonitis. Although the addition of sugars to the irrigation fluid removes excess water from the body, there is a risk of metabolic disorders. In Germany, PD is used in about 1-7% of patients.