Plasmapheresis means "plasma separation." This medical procedure consists of exchanging a patient's blood plasma (the watery part of blood) with a replacement solution. First, blood is withdrawn so that the plasma can be separated from the blood cells. Once separated, the blood cells are recombined with a replacement solution that resembles plasma, and the new mixture is then transfused back into the patient. Plasmapheresis is also called plasma exchange.

Blood plasma contains antibodies and other substances that play a role in many autoimmune/immune mediated diseases. Plasmapheresis has been successfully used for decades to treat many conditions, including autoimmune diseases like myasthenia gravis (a rare muscle disease) and Guillain-Barre Syndrome (a disease thought to result from an abnormal immune response to a virus). Because MS is also an immune mediated disease, plasmapheresis is a very promising treatment. This procedure was used occasionally to treat severe MS in the early 90's, and recently gained attention when Mayo Clinic researchers noted "moderate to marked improvement" in 42 percent of patients treated. Some patients with severe problems, including paralysis and the loss of speech, experienced dramatic improvement, regaining full use of their arms, legs and speech.

Plasmapheresis is not a cure for MS, nor is it recommended for most patients. At this time, plasmapheresis is performed only on patients whose severe attacks are unresponsive to other treatments--only a very small proportion of those who have acute flares. Researchers hope to learn why this procedure works for some people and not for others. Some speculate that plasma exchange dilutes the damaging immune factors in the plasma.

Plasmapheresis is conducted while the patient reclines in a chair or lies on a bed. The patient may experience some discomfort, but the procedure is not painful.

A catheter is used to draw blood from a vein, usually in the crook of the patient's arm. The blood is then placed in a device known as a cell separator. The cell separator either spins the blood at high speed to separate the cells from the plasma or it passes the blood though a membrane that filters out the cells and allows only the plasma to penetrate.. The antibody-containing plasma is thrown away. The cells are combined with a replacement fluid (usually albumin or a synthetic fluid that mimics plasma) and returned to the patient through another tube connected to the hand or foot on the opposite side of the body. This arrangement allows the patient to have one hand free during the procedure, which takes several hours.

The patient is given an anticoagulant drug during plasma exchange to keep the blood from clotting. At any given time during the procedure, the amount of blood outside the patient's body is similar to the amount one would donate at a blood drive.

Dropping blood pressure is the most common problem experienced during plasmapheresis. Patients whose blood pressure is falling may feel dizzy, faint, cold or sweaty, or experience blurred vision or abdominal cramps When these symptoms are reported, those attending the patient will assist by lowering the patient's head, raising the legs and administering IV fluids.

The anticoagulant medications given during the procedure can sometimes cause bleeding. These medications can also cause more serious reactions, such as an irregular heartbeat or seizures. These reactions can be avoided, however, if the patient reports the symptoms known to occur before the seizures or changes in heart beat: a metallic taste in the mouth, tingling around the mouth or limbs, or muscle cramps.

The most serious possible reaction is an allergic reaction by the patient to the plasma replacement fluids or the sterilizing agents used on the tubes. Itching, wheezing, or the eruption of a rash are signs of a medical emergency. If any of these symptoms occur, the procedure must be stopped immediately and IV medications administered.

Sometimes blood clotting problems continue after plasma exchange. Infections are also more likely at this time because the immune system may be extremely suppressed. This is because the desirable antibodies have been filtered out along with the undesirable ones. The body will eventually recreate the necessary antibodies, but patients need to be especially careful to guard against infections right after plasmapheresis. Antibodies can be administered intravenously, if necessary.

References

First published October 1, 1999
Last updated May 3, 2003
Copyright © 1999 Accordant Health Services, Inc. All Rights Reserved.

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