Apheresis

In therapeutic apheresis (from gr ἀφαιρέιν " take away " ), colloquially referred to as dialysis or blood purification method is a method for extracorporeal, ie taking place outside the body, removal of pathogenic ( disease-causing ) ingredients (proteins, protein-bound substances and cells) from the blood or blood plasma of the patient. After the removal of pathogenic agents is fed back " purified " blood again.

Therapeutic apheresis is a recognized treatment method and is carried out in various ways:

Apheresis can be used as a method of a healthy human to obtain blood components, which are used as the donor substance. In contrast to whole blood donation, this method allows to gain individual blood components in high purity and yield. Apheresis procedures are used to thrombocytes ( platelets), blood plasma, erythrocytes (red blood cells) or peripheral blood stem cells (see Stammzellapherese ) to collect.

Only with the help of apheresis procedures, it is possible from individual donors to gain sufficient quantities and of such blood components that make up only a small portion of the blood ( eg, platelets, blood stem cells). Thus, modern methods of treatment for cancer are only through the apheresis been opened, such as the transplantation of blood stem cell preparations and then the required substitution with high-dose platelet preparations.

In apheresis donor's blood is taken from the arm vein and passed into a closed, sterile and only single-use tube system ( apheresis kit). There it is mixed with a small amount of anticoagulant, inter alia, citric acid ( sodium citrate) containing that prevents the coagulation of blood in the apheresis system.

The blood / anticoagulant mixture is fed into a centrifuge, the blood components separate into its artificial gravitational field according to their density in layers. Those blood components to be obtained, can now be collected. Apheresis preparations with only a blood component are often obtained, but also multi-component efficient methods have been developed in recent years in which a plurality of blood components may be collected in parallel. All blood components are not required are returned to the blood donor. Here, the anticoagulant is immediately degraded by the liver so that the coagulation of the dispenser is unaffected.

Depending on the type of samples to collect blood components, constitution of the donor and apheresis system used, the duration of apheresis is very different:

• 30-75 minutes for the collection of plasma
• 20-30 minutes to collect erythrocytes
• 40-90 minutes for the collection of platelets
• 90-240 minutes for the collection of blood stem cells

For the blood donor apheresis procedures are very stressful. Side effects can include, inter alia, responses to the anticoagulant ( eg, metallic taste, tingling in the lips, mouth and extremities ) occur and in rare cases nausea.

Apheresis is also used for the treatment of various blood diseases. On the rare disease polycythemia vera form in particular too many erythrocytes (red blood cells ) that can be brought to a standard size by hemodialysis.