Plasmapheresis
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Plasmapheresis (from the Greek plasma, something molded, and apheresis, taking away) is the removal, treatment, and return of (components of) blood plasma from blood circulation. It is thus an extracorporeal therapy.
[edit] Description
During plasmapheresis, blood is initially taken out of the body through a needle or previously implanted catheter. Plasma is then removed from the blood by a cell separator. Three procedures are commonly used to separate the plasma from the blood:
Discontinuous flow centrifugation - One venous catheter line is required. Typically, a 300 ml batch of blood is removed at a time and centrifuged to separate plasma from blood cells.
Continuous flow centrifugation - Two venous lines are used. This method requires slightly less blood volume to be out of the body at any one time as it is able to continuously spin out plasma.
Plasma filtration - Two venous lines are used. The plasma is filtered using standard hemodialysis equipment. This continuous process requires less than 100 ml of blood to be outside the body at one time.
Each method has its advantages and disadvantages. After plasma separation, the blood cells are returned to the person undergoing treatment, while the plasma, which contains the antibodies, is first treated and then returned to the patient in traditional plasmapheresis. (In plasma exchange, the removed plasma is discarded and the patient receives replacement donor plasma or saline with added proteins.) Medication to keep the blood from clotting (an anticoagulant) is generally given to the patient during the procedure. Plasmapheresis is used as a therapy in particular diseases. It is an uncommon treatment in the United States, but it is more popular in Europe and particularly Japan.
[edit] Indication
An important use of plasmapheresis is in the therapy of autoimmune disorders, where the rapid removal of disease causing autoantibodies from the circulation is required in addition to slower medical therapy.
Other uses are the removal of blood proteins where these are overly abundant and cause hyperviscosity syndrome.
Examples of diseases that can be treated with plasmapheresis:
- Guillain-Barré syndrome
- Chronic inflammatory demyelinating polyneuropathy
- Goodpasture's syndrome
- Hyperviscosity syndromes:
- Myasthenia gravis
- Thrombotic thrombocytopenic purpura (TTP)
- Wegener's granulomatosis
- Lambert-Eaton Syndrome
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| Apheresis (Plasmapheresis — Plateletpheresis — Leukapheresis) | Blood transfusion | Coombs test | Cross-matching | Exchange transfusion | International Society of Blood Transfusion | Intraoperative blood salvage | ISBT 128 | Transfusion reactions |
| Human blood group systems - Blood type |
| ABO | Colton | Duffy | Hh | Kell | Kidd | Kx | Rhesus |Yt |
| Blood products |
| Blood | Blood donation | Blood substitutes | Cryoprecipitate | Platelets | Plasma | Red blood cells |
