Some Concepts On Plasma Exchange Therapy

By Kathleen Brooks


Advances in medicine have made it possible to manage certain conditions whose treatment posed a great challenge. Plasma exchange therapy, also known as plasmapheresis, is one of these advances. It involves getting rid of defective blood and replacing it with a functional one. In this procedure, entry to the system is accessed through a peripheral vein. A cannula connected to a catheter is inserted in to the vein. Once blood is drawn out, a special machine is used to separate the liquid part(plasma) from the cells. The cells are then mixed with new plasma and returned to the body.

Plasma exchange is one of the procedures that can done on an outpatient basis. It does not require anesthesia unless access is via a central line, in which case local anesthesia is sufficient. A central line refers to the use of larger veins such as those in the neck and around the shoulder to gain access to the venous system. This approach is indicated when the doctor is unable to cannulate the commonly used peripheral veins for one reason or another. Maintaining adequate hydration before and throughout the entire process is key.

Conditions in which toxic proteins exist in the plasma benefit most from this therapy. The relapsing form of multiple sclerosis is an example. However, treatment with plasmapheresis is only used when other forms of therapy have failed. It also helps control an acute attack. Other conditions that benefit include myasthenia gravis, thrombocytopenic purpura, atypical hemolytic uremic syndrome among others.

Complications can occur in the process, immediately after or days after. One of these complications is rejection of the new blood. If the patient has reacted in previous procedures, the doctor is required to give medications that prevent allergy prior to performing the exchange. Another common complication is infection which can be minimized by keeping the process as sterile as possible.

Another typical complication is the formation of clots once the blood leaves the body. This does not routinely occur because of the strict measures put in place. Sodium citrate, given as an infusion, binds calcium, the element needed for clots to form. Unfortunately, this puts the patient at risk of hypocalcemia (low levels of calcium in blood).

Hypocalcemia can result in multisystem fatalities if left untreated and if it is not detected in time. One needs to look out for tingling sensation and numbness in the extremities. In severe cases, patients may become irritable, go into fits, complain of difficulty swallowing and may have difficulty breathing. Hypocalcemia should therefore be anticipated and taken care of through calcium infusion.

Each session takes about two to four hours. In a week, two or three treatments may be needed. A full course takes a minimum of two weeks. Thereafter, the individual shows improvement lasting a few weeks to months. If condition relapses, they may have to undergo further courses of therapy.

In conclusion, it is important to note that plasma exchange may not provide a permanent cure for disease. As a matter of fact, it is only ideal for symptomatic treatment and for those who can afford it. Otherwise, the primary treatment should be continued alongside the therapy.




About the Author: