Index
What is Plasmapheresis?
It is used to refer to a wide range of procedures in which the extracorporeal separation of blood components results in a filtered plasma product.
Complete filtration can be achieved by centrifugation or using semipermeable membranes. Centrifugation takes advantage of the differences inherent in blood products, such as red blood cells, white blood cells, platelets, and plasma.
The plasma separation uses differences in the size of the particles to filter the plasma of the cellular components of the blood.
Traditionally, in the United States, most plasmapheresis is performed with automated technology based on centrifuges.
In some instances, particularly in patients already on hemodialysis, plasmapheresis can be carried out using semipermeable membranes to filter the plasma.
The filtered plasma is discarded in the therapeutic plasma exchange using an automated centrifuge. The red blood cells are returned to the patient, and the replacement colloid, such as the donor plasma or albumin.
In plasma filtration, fractionation of the secondary membrane plasma can selectively eliminate unwanted macromolecules, allowing the return of the processed plasma to the patient instead of the donor plasma or albumin.
Indications
Plasmapheresis is currently used as a therapeutic modality in various conditions; it is generally used when a substance in plasma, such as immunoglobulin, is highly toxic and can be eliminated efficiently.
Multiple conditions that fall into this category (including neurological, hematological, metabolic, dermatological, rheumatologic, renal diseases, and intoxications) can be treated with plasmapheresis.
The Apheresis Applications Committee of the American Apheresis Society periodically evaluates possible apheresis indications and classifies them from I to IV based on available medical literature.
The following are some of the indications and their categorization of society guidelines:
Category I (disorders for which apheresis is accepted as first-line therapy, either as an independent primary treatment or together with other modes of treatment) are the following:
- Síndorme of Guillain-Barre.
- Myasthenia gravis.
- Chronic inflammatory demyelinating polyneuropathy.
- Hyperviscosity in monoclonal gammopathies.
- Thrombotic thrombocytopenic purpura.
- Goodpasture syndrome (unless it is dialysis-dependent and there is no diffuse alveolar hemorrhage).
- Hemolytic uremic syndrome.
- Wilson’s disease
Category II (disorders for which apheresis is accepted as second-line treatment, either as an independent treatment or together with other modes of treatment) are the following:
- Lambert-Eaton myasthenic syndrome.
- Multiple sclerosis (acute demyelinating central nervous system disease that does not respond to steroids).
- Fungal poisoning
- Acute disseminated encephalomyelitis.
- Hemolytic uremic syndrome (atypical, due to mutations of the complement factor).
- Autoimmune hemolytic anemia (potentially deadly cold agglutinin disease).
- Systemic lupus erythematosus.
- Nephropathy
Category III (the optimal function of apheresis therapy is not established, decision making must be individualized) is as follows:
- Purple post-transfusion.
- Autoimmune hemolytic anemia.
- Hypertriglyceridemic pancreatitis.
Category IV (disorders in which published evidence demonstrates or suggests that apheresis is ineffective or harmful, the approval of the institutional review committee is desirable if the treatment of apheresis is carried out in these circumstances) are the following:
- Rigid person syndrome.
- Hemolytic uremic syndrome.
- Systemic lupus erythematosus.
- Immune thrombocytopenia
Contraindications
Plasmapheresis is contraindicated in the following patients:
- Patients who can not tolerate the placement of the central line.
- Patients who have allergies to fresh frozen plasma or albumin, depending on the type of plasma exchange
- Patients with heparin allergies should not receive heparin as an anticoagulant during plasmapheresis
- Patients with hypocalcemia risk worsening their condition because citrate is commonly used to prevent coagulation and may potentiate hypocalcemia.
- Patients taking angiotensin-converting enzyme inhibitors should stop using the drug for at least 24 hours before starting plasmapheresis.
Technical considerations
Although the term plasmapheresis refers technically only to plasma removal, it is also widely used to encompass the therapeutic plasma exchange in which a replacement is transfused after plasma extraction.
The applications include the following:
- Erythrocytapheresis (selective elimination of red blood cells) is used in sickle cell anemia or malarial infection. Red blood cells are selectively removed and replaced with donor erythrocytes.
- Leukapheresis (selective elimination of white blood cells) is used in conditions such as hyperleukocytosis, where a high number of pathological leukocytes is present (for example, in leukemia).
- It can also collect peripherally circulating stem cells that can be infused into an autologous or allogeneic stem cell transplant.
- Platelet apheresis (selective platelet removal) can be used in conditions of thrombocytosis.
Prevention of complications
It is essential to have all the equipment and medications needed for the procedure available at the beginning to minimize complications. A sterile technique is advised to reduce the likelihood of infection.
