This information sheet answers some of the common questions patients ask about plasma exchange. Further information can be found from your consultant neurologist, specialist nurse or pharmacist.

What is plasma exchange?

Plasma exchange is the process of removing the plasma component of your blood (the liquid yellow - coloured portion), which contains the antibodies thought to be responsible for your myasthenia gravis, and replacing the plasma with alternative plasma which does not contain antibodies.

What does plasma exchange involve?

Plasma exchange involves using a machine called a "cell separator" which separates the blood into its various parts. It takes away the plasma portion of your blood and gives you back replacement plasma. This will normally be a "processed" plasma product, although occasionally you may need fresh plasma. All the other parts of your blood will be returned to you during the treatment.

A needle will be inserted into a large vein in each arm. Local anaesthetic will be given to freeze the skin before inserting the needle. The "cell separator" machine will then draw your blood from the needle in one arm, spin off the plasma and return the rest of the blood through the needle in the other arm. It is important that there is a good flow of blood. Occasionally there may the need to move the needle to another vein if the blood flow is poor.

What should I expect while being on the machine?

The process of plasma exchange normally takes 2 to 3 hours. The amount of plasma in your system is calculated by using your height, weight and blood count. This determines how long the treatment will take.

You may have your plasma exchange as an out-patient or inpatient depending on your general health status and how stable your myasthenia is. This will need to be checked with the hospital.

The machine will be attached while you rest on a reclining bed or chair. An anticoagulant solution is added to your blood to prevent it clotting the machine and this may cause tingling in your lips, nose or fingers. If this happens it is important to the nurse or doctor know immediately. Sometimes people can feel light-headed or faint while having plasma exchange. Again, let the nurse or doctor know if this happens as this can often be treated by tilting the chair back a bit or stopping the procedure for a little while.

What should I do for the process?

• Make sure you discuss all your medicines with your doctor. For example, any medicines for high blood pressure or heart problems. You may need to miss a dose or delay taking them until after the procedure is done. Most medications are not removed from the body to nay great level by plasma exchange, but there are some important exceptions to this.
• If you are having blood samples taken out with this procedure, it is important that they are taken from the veins in the back of your hand rather than the large veins at your elbow. These larger veins need to be preserved for the purpose of the plasma exchange. If it appears that the veins in your arms are not suitable, it may be necessary to have a special tube inserted into a larger vein, which would be done under local or general anaesthetic. This should be discussed prior to the procedure.
• Make sure you have eaten before each procedure. However, you can eat normally during a plasma exchange. If possible, you should try and eat calcium-rich foods, such as milk, yoghurt, chocolate or cheese, to help reduce the risk of "tingling".
• You should try and go to the toilet before being attached to the machine.
• You can have a friend or relative sit with you during the procedure and you can also bring your own books, newspapers, MP3 players or DVD to help pass the time. This will need to be checked with your hospital.

What should I do after the procedure?

People can often feel quite tired after the procedure. Therefore it is recommended that you do not drive but have a friend or relative collect you after the procedure. It is also recommended that you do not drink alcohol or do physical exercise for 24 hours after the procedure.

The number of plasma exchanges you have will depend upon your myasthenia and how it has responded to the treatment. You may require an exchange every day for 5 days or possibly only 3 times a week. Your doctor will discuss with you whether the plasma exchange will need to be repeated. Although plasma exchange can improve your myasthenia, it will not cure it. Therefore it will often be used with other medications for myasthenia and you should discuss this with your doctor.

Where can I obtain further information?

If you would like further information about plasma exchange or if you have any concerns about your treatment, you should discuss this with your doctor or nurse.