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