Overview of Exchange Transfusion
Therapeutic plasma exchange (TPE) is a treatment method that involves taking out your blood or plasma (a part of your blood that contains important proteins), removing harmful substances from it, and replacing it with a substance called a colloid solution, which could be made up of a protein called albumin and/or donated plasma. This is done to get rid of something harmful in your system. The amount of plasma that is exchanged generally ranges from 1 to 1.5 liters and the goal is to remove things like dysfunctional cells, harmful antibodies, products of cell activity, bacteria or parasites, and harmful substances.
There are two ways to separate the plasma for this treatment – a manual method and an automated method. The manual method involves drawing your blood, spinning it in a machine to separate the plasma from the rest of the blood, taking out the plasma, and then returning the rest of the blood back to your body. The automated method does the same thing, but it uses a special machine called a plasmapheresis machine. This machine can do the whole process in a continuous flow.
The process of removing and replacing the plasma means that the concentration of different things in your blood gets diluted. With one round of this treatment, about 66% of the harmful substances are removed. If a second round is done, about 85% are removed, and with a third round, approximately 93% are removed. How well TPE works in getting rid of a harmful substance depends on the size of that substance, the rate at which it’s being produced in your body, and where in the blood it’s located.
Why do People Need Exchange Transfusion
The 2019 guidelines from the American Society for Apheresis includes an extensive list of diseases for which therapeutic plasma exchange (TPE) is appropriate. TPE is a blood cleaning procedure used to manage diseases, with the specifics of its use clearly detailed in these guidelines. Let’s examine the key conditions where TPE is useful:
Sickle cell disease is a genetic disorder that can cause red blood cells to turn into a sickle shape, making it difficult for them to travel through blood vessels. The lifespan of these abnormal cells is short, which can result in anemia, risk of getting bacterial infections, painful episodes known as “sickle cell crises”, and other complications. TPE is recommended for severe anemia and organ failure in these cases. The goal is to reduce pain episodes by lowering sickle-shaped hemoglobin and increasing the oxygen-carrying hemoglobin.
Neonatal polycythemia is a condition in newborns where there is a higher than normal number of red blood cells, which can thicken the blood. This can happen due to genetic abnormalities, twin-to-twin blood transfer in the womb, or growth restriction during pregnancy. If not quickly treated with fluid, these babies might develop symptoms like low blood sugar, blue-colored skin, or respiratory issues. TPE is used for these babies if initial treatments are not effective.
Neonatal hyperbilirubinemia is when a newborn has high levels of bilirubin, a yellow substance made during the body’s normal breakdown of old red blood cells, in the blood. It could either be physiological (temporary increase in red blood cell production and bilirubin metabolism) or pathological (several diseases involving immune-mediated destruction of red blood cells). Babies with this condition can risk brain damage, and while light therapy is the main treatment, TPE can also be used if bilirubin levels remain high despite this therapy.
Babesiosis is an illness caused by a blood parasite and can cause flu-like symptoms and anemia (low red blood cell count). TPE is used in severe cases to reduce the parasite burden, correct anemia, and remove harmful substances produced during an immune response.
Guillain-Barre syndrome (GBS) is an immune disorder that affects the insulation of the peripheral nervous system, often precursored by gastrointestinal or respiratory infections. Symptoms start with numbness and weakness on both sides of the body and can be life-threatening if it affects the heart and lung workings, or causes severe chest muscle weakness. In this case, TPE is used alongside other treatments until an ongoing decrease in a blood protein (plasma fibrinogen) is seen.
Myasthenia gravis is a condition where the body’s immune system attacks certain receptors in muscles, leading to muscle weakness. It is triggered by antibodies against a certain receptor (acetylcholinesterase) present in our muscles. These patients offer show weakness in their eye, mouth, and facial muscles, and can even experience paralysis in severe instances, known as a myasthenic crisis. In these cases, TPE is used to remove these particular antibodies and improve muscle strength and breathing.
Heparin-induced thrombocytopenia (HIT) is a condition where the drug heparin triggers the body to produce antibodies that activate platelets, leading to a higher possibility of developing blood clots. In severe or persistent cases, TPE is used to remove these antibodies.
Lastly, thrombotic thrombocytopenic purpura (TTP) is a rare blood disorder where blood clots form in small blood vessels throughout the body. This can limit oxygen supply to organs, leading to severe issues. It is often deadly and has a mortality rate over 90% if not treated. TPE is the primary treatment for TTP.
Equipment used for Exchange Transfusion
To get ready for your treatment, the doctor will first prepare two spots on your body where they can insert needles. This is known as intravenous access. Then, they’ll use tools called catheters and tubing to connect you to the medical equipment.
The doctor will also use a machine called a centrifuge, which spins really fast (about 2000-2500 rounds per minute). The spinning separates your blood’s components, similar to how you might see oil and water separate. If a centrifuge is not used, a plasma separation filter may be employed. This tool works like a sieve; allowing the small proteins (like albumin) to pass through and retaining the larger ones (up to the size of an IgM, which is a type of immune protein).
Your blood will then be treated with an anticoagulant – this is a substance that stops your blood from clotting. You might have heard of some of these before, like citrate or heparin. Once treated, it’ll be mixed with a replacement fluid, which could be a protein called albumin, or fresh frozen plasma, which is a component of blood.
Who is needed to perform Exchange Transfusion?
For the procedure called TPE to be done, there are some important people involved. These include the pheresis technician, a doctor specialized in studying diseases called a pathologist, a blood doctor known as a hematologist, and your personal doctor managing your treatment. Good communication between all these individuals is very important for your swift and successful treatment.
How is Exchange Transfusion performed
Therapeutic plasma exchange is a procedure which removes, treats, and returns the blood plasma from circulation. There are two main types of plasma exchange: centrifugal and membrane. Here’s an easy way to understand both:
Centrifugal Therapeutic Plasma Exchange is like a constantly moving loop that takes blood from the patient, moves it through a machine (the centrifuge), and then returns it back to the patient. Inside this machine, a substance called citrate is added to the blood. Citrate prevents the blood from clotting too soon. Then, the machine spins the blood around very fast. This spinning causes the plasma (the liquid part of the blood) to separate from the heavier parts of the blood like the white and red blood cells. The machine then removes the plasma, treats it, then recombines it with a replacement fluid, which could be a substance called albumin or another blood component called fresh frozen plasma, before returning it back to the patient.
Membrane Therapeutic Plasma Exchange also involves a constantly moving loop that sends blood from the patient, moves it through a filter, and then sends it back to the patient. For this method, a different anti-clotting substance, heparin, is used. The filter used here has very small holes and separates the plasma from the other heavier parts of the blood based on their size and distribution. This way, the plasma can be removed, treated and mixed again with a replacement fluid, either albumin or fresh frozen plasma, before it is retuned back to the patient.
Both of these methods are designed to treat certain conditions which affect the blood plasma, and the choice of method would usually depend on your doctor’s decision and your specific situation.
Possible Complications of Exchange Transfusion
After receiving a medical procedure, there are some risky complications that could potentially happen, like getting an infection, having severe bleeding, a blood clot, and in some cases, the procedure itself could be fatal. Additionally, some people have severe reactions to blood or plasma transfusions, such as severe allergies or the body attacking the new blood. A recent study looked at plasma exchange procedures, which is when doctors replace some of your body’s plasma, in 435 children. The main complications that happened were itchiness or hives (in 7%), high blood pressure (in around 2%), and low blood pressure (in around 1%). Some serious complications occurred in 5 patients (which is 0.42%) – these included a fungal infection, a severe allergic reaction and a severe skin reaction.
What Else Should I Know About Exchange Transfusion?
Therapeutic plasma exchange, also known as TPE, is a special procedure that helps remove harmful substances from your blood. Usually, it is used as a supplemental treatment or when initial treatments didn’t work. The Journal of Clinical Apheresis offers guidelines for when to use TPE based on the specific disease and the patient’s condition.
Using TPE can be complex and requires a team of healthcare professionals working together. This coordination ensures the safety of the patient, guarantees that the treatment is suitable for the specific circumstance, and that any other treatments that might be needed are applied. This customized approach is key to get the best possible result for each patient.
