Apheresis

calculation for plasma volume

blood = patient weight in kg x 70 ml/kg plasma volume = blood vol x (1.0-Hct)

vascular access

blood flow rates for adults is ~60-250 ml/min for small kids may be down to 10 ml/min

acute/chronic inflammatory demylinating polyreadiculneuropathy, myasthenia gravis, PANDAS

category 1

extracorproeal photopheresis

immunomodulatory therapy leukopheresis ex-vivo irradiation of lymphocytes in the presence of 8-methoxypsoralen (8 MOP) reinfusion into the patient

category 3 of ASFA guidelines

insufficient data to determine effectiveness; results of clinical trials may be conflicting or uncontrolled anecdotal reports of efficacy

graft rejection of transplantation

is characterized by a clonal expansion of activated T cells CTCL is also characterized by a clonal population of T cells

b/c of the diminishing effect of increased plasma removal...

it is recommended that approx. 1 to 1.5 plasma volumes be exchanged per procedure

sickle cell disease

maintenance of hgb S <30% has been proven to prevent recurrent stroke in sickle cell patients when rbc exchange is stopped, risk for stroke returns

therapeutic plasma exchange (TPE)

removal and retention of the plasma, with return of all cellular components removal of an offending antigen in the plasma replace a normal factor or substance that may be missing or deficient in the patient's plasma

PTT, TT

returned to normal 4 hours post exchange PT returned to normal 24 hours post exchange

what is erythroytapheresis used for?

sickle cell disease, thalassemia, malaria, babesiosis reduces risk of iron overload

graft vs host disease

skin: category 2 (acute and chronic) non-skin (acute/chronic): category 2

category 2 of ASFA guidelines

supportive or adjunctive to other therapy

red blood cells

typically collected as a double unit (2RBC or double RBC procedure)

one plasma volume exchange

IgG drops to 34% of baseline IgA drops to 39% of baselines IgM drops to 31% of baseline varying reports as to time to recovery of Ig ranges from 3 days to 5 weeks for full recovery

lung transplant

rejection = category 2

clotting proteins recovery

85-100% of baseline within 24 hours elevation of PTT, PT, TT post exchange

patient's extracorporal blood vol (EBV) should be

<15% of the total blood volume (TBV) in order to minimize risk of hypovolemia

apheresis was developed by

Dr. edwin J. cohn based on dairy centrifuge

FFP recommended only in cases of...

TTP or hemolytic uremic syndrome (HUS) there is a possibility of disease transmission with use of FFP

two common methods of centrifugation

- intermittent flow centrifugation (IFC) - continuous flow centrifugation (CFC) there are advantages and disadvantages to both

assumptions for therapeutic apheresis

- no equilibration with extravascular stores - assumes no further substance is produced - predicts 37% of substance remains at end of 1 plasma volume exchange - 22% remaining 1.5 PV exchange - 14% remaining after 2.0 PV exchange

indication categories for therapeutic apheresis

1, 2, 3, and 4

fraction of cells remaining is typically

30% is used goal Hct 30%

ECP combines...

PUVA and leukoapheresis cytoreduction for leukemic CTCL response rate for all stages of disease ~55% and a complete response in ~18%

equation for removal of substance in plasma:

Y = Y^0e^x Y = final conc Y^0 = initial conc e = natural log X = number of times patients total plasma volume is exchanged

apheresis can be performed on

a donor to collect a specific blood component (donor apheresis) it can be performed on a patient to remove a particular blood component for therapeutic purposes (therapeutic apheresis)

what is therapeutic apheresis?

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 mechanism

who is responsible for apheresis program?

a qualified, licensed physician is responsible for all aspects

transplant tolerance

acquired state of non-responsiveness to donor alloantigens

erythrocytapheresis

aka Red Cell Exchange removes a large number of RBCs form the patient and returns the patient's plasma and platelets with compatible allogenic donor RBCs

what is added during apheresis

anti-coagulants or sedimenting agents

what are the key players in tolerance?

apoptotic cells dendritic cells (engulf apoptotic cells) T reg cells (central role in maintaining immune homeostasis)

membrane separators

are typically composed of bundles of hollow fibers or flat plate membranes with specific pore sizes

anticoagulant - ACDA (citrate)

chelates calcium and block calcium dependent clotting factor reactions ensures extracorporeal blood reamins in fluid state minimize activation of platelets and clotting factors

what are some adverse effects of apheresis?

citrate toxicity vascular access difficulties vasovagal reactions hemolysis allergic rxns due to ethylene oxide used in sterilization of apheresis kit air embolism circuit clotting

hyperviscostity syndrome

concentration of paraprotein at which patients develop clinical hyperviscosity is variable for IgM, reduction of serum viscosity may occur with removal of 0.5 plasma volume

category 1 of ASFA guidelines

considered primary or standard therapy usually on the basis of controlled trials

what others are category 1?

cutaneous T cell lymphoma cryoglobulinemia(severe/symptomatic) leuko/thrombocytosis TTP post transfusion purpura sickle cell (Acute stroke) hyperviscosity in monoclonal gammopathies

central tolerance

developing lymphocytes are rendered tolerant to self

variation is due to...

different methods of calculating recovery, some patients on immunosuppressive medications

category IV of ASFA guidelines

do not respond to apheresis therapy

peripheral tolerance

mature, autoreactive lymphocytes in the periphery anergy and apoptosis T-regulatory cells

removal of autoantibodies

monoclonal immunoglobulins paraproteins polyclonal autoantibodies antibodies in immune complexes

replacement fluid

need replacement fluid to exert oncotic pressure to replace removed plasma - 5% albumin - FFP - 5% albumin and normal saline (usually cannot use less than 30% of 5% albumin and 70% NS)

symptoms of hypocalcemia

oral paresthsia nausea/vomiting lightheadedness shivering, twitching, tremors worsening of myasthenia gravis during exchange muscle cramping tetany QT prolongation may cause metabolic alkalosis if renal disease and using FFP

blood separation

plasma- sg of 1.025-1.029 platelet- sg of 1.040 mononuclear - 1.070 granulocyte - 1.087 RBC - 1.093-1.096

apoptotic cells

promote an anti-inflammatory environment conducive for tolerance decrease expression of pro-inflammatory cytokines and vital co-stimulatory proteins on AFC increase expression of anti-inflammatory cytokines PROMOTION OF TOLEROGENCI PHENOTYPE

cardiac tranplant

prophylaxis: category 2 treatment for cellular rejection: category 2

what is the clinical advantages to 2rbc?

reduced donor exposure for the recipient because the patient can potentially recieve 2 units from the same individual

leukapheresis

used for WBC collction in cases of leukemia to reduce sludging in vessels and improve oxygenation to collect stem cells for autologous/allogenic bone marrow transplants collect dendritic cells as part of new vaccine therapies used in prostate cancer, glioblastoma multiforma, and renal cell carcinoma HES (red cell sedimenting agent)

plateletpheresis

used to collect platelets for blood banks also used to reduce platelet count in diseases such as essential thrombocytopenia where platelets counts can be very high

modern apheresis instruments

utilize a computerized control panel, allowing the operator to select the desired component to be collected or removed -onboard optical sensors -use of disposable kits -duration of the procedure varies

the number of TA produces performed

varies with the disease/disorder and the individual patient use of blood warmers during TA

flow rate depends on

vascular access ability to tolerate citrate (related to TBV)

what is apheresis

withdrawing a small volume of whole blood from a donor or patient and separating into its components one or more of the components is collected and retained, and the remaining components are recombined and returned to the individual