MLS 413: Apheresis

Apheresis

- ("a taking away") •whole blood is removed from the body •passed through an apparatus that separates out one (or more) particular blood constituent. •remainder of the constituents returned to the individual's circulation.

In a collection tube what is does the plasma consist of?

- 91.5% water - 7% proteins - 1.5% other solutes

Plasma Protein Interactions

- The concentration of most plasma substances is reduced by 50% to 60% after one standard plasmapheresis treatment, with the rate of return to steady state concentrations varying among analytes

Charcoal

removal of bile acids

Polymyxin B

removal of endotoxin

Cellulose acetate

removal of granulocytes

Component Collection

- A specific blood component is obtained that will be transfused to a patient. •General and apheresis-specific donor requirements - Collection of each apheresis blood component carries with it a different deferral period. - A qualified, licensed physician must be responsible for all aspects of the apheresis program. •Other staff requirements - Written, informed consent must be obtained from the donor, including statements of risk.

Therapeutic Apheresis (TA) — Vascular Access

- Adequate vascular access is mandatory. - peripheral veins, central veins, or a combination of both - patient must have adequate veins at two sites capable of accommodating a 16- to 18-gauge needle

Category I

- Apheresis as a first line treatment alone or in conjunction with other treatments

Category II

- Apheresis is a second line treatment alone or in conjunction with other treatments

Category IV

- Apheresis is reported as either as no benefit or potentially harmful in this conditions

Platelets

- Apheresis platelets provide the equivalent of 6 to 8 units of random-donor platelets. - This significantly decreases the patient's donor exposure. - Additional donor selection criteria for the plateletpheresis donor.

Adverse Effects of Apheresis

- Citrate toxicity - Vascular access difficulties - Vasovagal reactions - Hypovolemia - Allergic reactions - Hemolysis

Therapeutic Apheresis (TA) — General Considerations

- Clearly defined policies must delineate the responsibility of the blood bank physician and the patient's attending physician(s). •American Society for Apheresis (ASFA) guidelines for Therapeutic Apheresis

History and Development

- Early developments in apheresis began some 60 years ago when Dr. Edwin J. Cohn devised a method, based on a dairy centrifuge (the "Cohn centrifuge"), for purification of albumin from pooled human plasma.

What is the process of of removing red blood cells?

- Erythrocytoapheresis

Hematopoietic Progenitor Cells (HPCs)

- Hematopoietic growth factors •commonly used prior to the collection procedure to increase the number of circulating stem cells in the peripheral circulation. •Anesthesia is avoided; procedures performed safely in the outpatient setting. •autologous HPC donors have a shorter period of cytopenia, decreased transfusion requirements, fewer infectious complications, and decreased length of hospitalization.

Physiology of Apheresis

- Impact of the manipulation of the removed blood, and subsequent reinfusion of portions of the blood back to the donor's body

Fluid Replacement

- In therapeutic plasmapheresis, large volumes of the patient's plasma are retained. •Replacement is necessary to maintain appropriate intravascular volume and oncotic pressure. •Several options are available, determined by the disease being treated, the condition of the patient, and the preference of the institution. •Use of 5% human serum albumin vs. FFP.

What is the process of of removing or collecting leukocytes?

- Leukapheresis

Membrane Filtration

- Membrane separators are typically composed of bundles of hollow fibers or flat plate membranes with specific pore sizes. - Pores can be sized to prevent the passage of even small cellular elements during plasma collection. - There are advantages over centrifugation methods.

Methodology of apheresis

- Modern apheresis instruments utilize a computerized control panel, allowing the operator to select the desired component to be collected or removed. - By manipulating certain variables on an apheresis instrument, the operator can harvest plasma, platelets, WBCs, or RBCs.

Granulocytes

- Patient populations that may benefit - Provides a higher yield product than whole blood - Minimum therapeutic dose considerations - Side effects of the addition of the red cell sedimenting agent, hydroxyethyl starch (HES) - Use of oral corticosteroids to mobilize marginal pool granulocytes and increase circulating cells - Considerations for administration of granulocyte-colony stimulating factor (G-CSF) - Consideration of GVHD in severely immunocompromised patients - Compatibility testing requirements

What is the process of of removing plasma?

- Plasmapheresis

What is the process of of removing platelets?

- Plateletpheresis

Fatalities

- Rare fatalities during therapeutic apheresis procedures have been reported. •Most caused by circulatory (cardiac arrest or arrhythmia) or respiratory complications (acute pulmonary edema or adult respiratory distress syndrome) •FFP recommended only in cases of TTP or hemolytic uremic syndrome (HUS) •There is a possibility of disease transmission with use of FFP

In a collection tube what is the bottom layer?

- Red blood cells

Therapeutic Plasma Exchange (TPE)

- Removal and retention of the plasma, with return of all cellular components •Removal of an offending agent in the plasma •Replace a normal factor or substance that may be missing or deficient in the patient's plasma - Because of the diminishing effect of increased plasma removal, it is recommended that approximately 1 to 1.5 plasma volumes be exchanged per procedure.

Erythrocytapheresis (Red Cell Exchange)

- Removes a large number of RBCs from the patient and returns the patient's plasma and platelets with compatible allogeneic donor RBCs. •Most commonly performed to reduce complications of sickle cell disease •Therapeutic goal: removal of incompatible RBCs from patient's circulation •Less common indications for red cell exchange •Requirements for allogeneic donor red cells

Therapeutic Apheresis (TA) — Physiologic Considerations

- The patient's extracorporeal blood volume (ECV) should be <15% of the total blood volume (TBV) in order to minimize the risk of hypovolemia. •Calculation of the patient's plasma volume (PV) •Consideration of the patient's medications - The number of TA procedures performed varies with the disease/disorder and the individual patient. Use of a blood warmer during TA

Therapeutic Apheresis (TA)

- The rationale is based on •A pathologenic substance exists in the blood that contributes to a disease process or its symptoms. •The substance can be more effectively removed by apheresis than by the body's own mechanisms. - Cytapheresis procedures - Plasmapheresis procedures

Plateletpheresis is used for what?

- Therapeutic plateletpheresis is used to treat thrombocythemia with related symptoms. •Risk of thrombotic or hemorrhagic complications •Use of medications versus plateletpheresis - There are no specific guidelines as to the level the platelet count must be reduced or a standardized procedure to reach a particular target platelet count.

Red Blood Cells

- Typically collected as a double unit (termed a 2RBC or double RBC procedure)

Leukapheresis

- Used to treat patients with hyperleukocytosis (defined as a WBC or circulating blast count of >100,000/µL) •Risk for organ dysfunction from microthrombi in the pulmonary and cerebral microvasculature •Prediction of required blood volume is difficult •Monitor with WBC counts •Use of a red cell sedimenting agent, such as HES, may be of benefit

Photopheresis

- Utilizes leukapheresis to collect the buffy coat layer from whole blood. •treated with 8-methoxypsoralen (8-MOP) •exposed to ultraviolet A (UVA) light •reinfused into the patient. •FDA approved for the treatment of cutaneous T-cell lymphoma. •has been used to treat acute and chronic graft-versus-host disease, solid organ transplant rejection, and selected immunologically mediated diseases.

In a collection tube what is does the buffy coat consist of?

- White blood cells - Lymphocytes - Granulocytes - Monocytes - Basophils - Neutrophils - Eosinophils - Platelets

Plasmapheresis

- collection of plasma by apheresis •Each apheresis unit ("jumbo" plasma) is the volume equivalent of at least two whole-blood-derived plasma units. - Varied purposes for collection of apheresis plasma - For donor purposes, collection divided into frequent and infrequent plasmapheresis Applicable FDA guidelines for plasmapheresis

Plateletpheresis

- collections should not be performed on potential donors taking antiplatelet medications. - Recommended intervals between plateletpheresis procedures according to regulatory guidelines established by the FDA and the AABB.

Immunoadsorption/Selective Absorption

- mmunoadsorption refers to a method in which a specific ligand is bound to an insoluble matrix in a column or filter. - Selective removal of the pathogenic substance - Reinfusion of the patient's own plasma and cellular components.

When is Apheresis performed?

- on a donor to collect a specific blood component (donor apheresis). - on a patient to remove a particular blood component for therapeutic purposes (therapeutic apheresis).

Category III

_ Treatments should be individualized based a clinical evaluation and assessment of the risks and benefits

What are the indication categories for therapeutic apheresis?

•Category I •Category II •Category III Category IV

What are the two common methods of centrifugation

•Intermittent Flow Centrifugation (IFC) •Continuous Flow Centrifugation (CFC)

Staphylococcal protein A

•a cell wall component of Staphylococcus aureus. •affinity for IgG classes 1, 2, and 4 and for IgG immune complexes.

What is the clinical advantage of red blood cells?

•reduced donor exposure for the recipient because the patient can potentially receive two units from the same individual •2001 FDA donor selection criteria