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Plasmapheresis
報告者: R2宋沛勳
日期: 2008-11-12
指導醫師: 蘇鈺壬醫師,王奕淳醫師
“Plasma” and “Aphaeresis”
Plasmapheresis exactly means the method
of plasma separator itself or the way for
plasma separation
Plasma exchange means the method of
substitution of plasma with other human’s
plasma or with other substitutional fluid
Blood separator technology is used to remove abnormal
blood cells and plasma constituents.
The terms plasmapheresis, leukapheresis,
erythrocytapheresis, and thrombocytapheresis
describe the specific blood element that is removed.
In plasmapheresis, or therapeutic plasma exchange (TPE),
large quantities of plasma are removed from a patient and
replaced with fresh frozen plasma (FFP), albumin solution,
and/or saline.
Aim
Plasmapheresis and plasma exchange is


To take out causative substances of the disease,
especially high molecular weight substances,
To supply normal plasma component
Blood purification
Hemodialysis: Blood/Dialysate circuit
Hemoperfusion: Biological adsorption
Hemofiltration: Solute removal
Plasma exchange
Double filtration
Blood transfusion
Molecular weight of removed substances
by blood purification therapy
Principles of treatment
Use of concomitant immunosuppression


High doses of corticosteroids
Cytotoxic agents, such as cyclophosphamide
 To reduce the rate of resynthesis of pathologic
antibodies and to further modulate cell-mediated
immunity
Treating early
 Plasmapheresis of anti-glomerular basement
membrane (GBM) disease is most effective if therapy
is initiated when serum creatinine is <5 mg/dL (440
mcmol/L).
Pharmacokinetics of immunoglobulin (Ig) removal
Reaccumulation
Lymphatic drainage into the vascular space
Endogenous synthesis
Pharmacokinetic basis for TPE prescriptions
One plasma volume exchange daily for 5
consecutive days at intervals of 24 hours to allow
for adequate lymphatic drainage into the vascular
space.
Being targeted to the specific macromolecule that is
pathogenic, if this is known.
If treatments are performed without identification of the
offending agent, then the physician remains dependent on
empirical treatment regimens.
Estimation of plasma volume
Approximately 35-40 mL/kg
Kaplan (1992): estimated plasma volume

Vp = [0.065 x weight (kg)] x (1 - Hct)
Plasma exchange
Double filtration
Plasma separator
Centrifugal separation
Membrane separation
 MW cutoff: 3 million (immune complex: 1 million)
 Pore size: 0.2 micrometer
 Sieving coefficient: 0.8-0.9

(Ig, C3, C4, fibrinogen, cholesterol, TG……)
Technical consideration
Comparison between centrifugal
and membrane separation
Centrifugal
Separation
Membrane
Separation
Cost of disposables
Economical
Expensive
Availability of continuous
performance
Depending on the
apparatus
Available
Modification
Complicated
Easy
Operation
Complicated
Easy
Contamination of platelet
Existing
Free
Separation of Blood cell
components
Available
Not available
Membrane plasma separators
Must be performed at low TMP (<500 mmHg) to
avoid hemolysis. (TMP: 40-50 mmHg)
The ideal blood flow rate (QB) is usually 100-150
mL per minute.



When the blood flow rate is 100 mL per minute, a plasma removal
rate of 30-50 mL per minute can be expected.
Thus, the average time required to perform a typical membrane
filtration (Ve = 2,800 mL) is <2 hours (40 mL per minute x 60
minutes = 2,400 mL per hour).
With hollow-fiber devices, the blood flow rate should exceed 50 mL
per minute to avoid clotting.
Anticoagulation
Heparin


Being used at an initial loading dose of 50
units/kg, followed by an infusion rate of 1,000
units per hour.
Frequent monitoring (half-hour) of the activated
clotting time (ACT) to maintain an ACT of 180220 seconds is desirable (1.5-2.0 times normal).
Citrate






Hypocalcemia
Acral paresthesias, light-headedness, twitching,
tremors, involuntary carpopedal spasm,
prolongation of the QT interval
Metabolic alkalosis
Liver disease
FFP containing up to 14% citrate
Tx: orally 500-mg calcium carbonate q30min or
10% calcium gluconate 10ml over 15-30 mins
Complications of plasmapheresis
Related to vascular access



Hematoma
Pneumothorax
Retroperitoneal bleed
Related to the procedure






Hypotension from externalization of blood in the
extracorporeal circuit
Hypotension due to decreased intravascular
oncotic pressure
Bleeding from reduction in plasma levels of
coagulation factors
Edema formation due to decreased
intravascular oncotic pressure
Loss of cellular elements (platelets)
Hypersensitivity reactions
Related to anticoagulation






Bleeding, especially with heparin
Hypocalcemic symptoms (with citrate)
Arrhythmias
Hypotension
Numbness and tingling of extremities
Metabolic alkalosis from citrate
Potential indications for plasmapheresis
Goodpasture syndrome (anti-GBM disease)
TTP/HUS
Cryoglobulinemia
Hyperviscosity syndrome (esp. Macroglobulinemia)
Myeloma cast nephropathy (controversial)
Acute demyelinating polyneuropathy (Guillain-Barre)
Homozygous familial hypercholesterolemia (selective
adsorption)
Myasthenia gravis crisis
Chronic inflammatory demyelinating polyneuropathy
Eaton-Lambert myasthenic syndrome
Posttransfusion purpura
Refsum disease
Cutaneous lymphoma (photopheresis)
HIV-related syndromes (polyneuropathy, hyperviscosity,
TTP)
Coagulation factor inhibitors
Rapidly progressive glomerulonephritis (without anti-GBM)
Paraproteinemic peripheral neuropathy
Systemic vasculitis associated with ANCA
ABO-incompatible marrow transplant
SLE (in particular SLE cerebritis)
Bullous pemphigoid
Pemphigus vulgaris
Immune thrombocytopenia (staphylococcal protein A
adsorption)
Hemolytic disease of the newborn
Indications for emergency plasmapheresis
Anti-GBM disease and/or pulmonary hemorrhage in
Goodpasture syndrome
Hyperviscosity syndrome with signs and symptoms
suggesting impending stroke or loss of vision
Microangiopathic thrombocytopenia (TTP/HUS)
Presence of very high factor VIII inhibitor levels in patients
requiring urgent surgery (the purpose of plasmapheresis is
to reduce the risk of intrasurgical and postsurgical bleeding
complications)
Respiratory insufficiency in Guillain-Barre syndrome
Myasthenia gravis with respiratory distress not responding
to medication
Acute poisoning with certain mushrooms or with other
strongly protein-bound poisons, such as parathion or
paraquat, depending on the severity of the intoxication
General orders for plasmapheresis
Calculate the plasma volume.
Measure the preplasmapheresis PT, PTT, and platelets.
When feasible, measure the plasma level of the substance
targeted for removal (e.g., anti-GBM antibody titer,
acetylcholine receptor antibody, cryoglobulin).
Space treatments approximately 24 hours apart (variable).
For heparin anticoagulation (low bleeding risk patient):





Heparin 50 units/kg initially, then 1,000 units per hour.
Target ACT (when baseline mean control value = 145 seconds)
during the procedure is about 180-220 seconds.
If the ACT is <3 minutes, increase the infusion rate by 500 units per
hour.
If the ACT is >4 minutes, discontinue heparin infusion, continue to
measure the ACT, and resume heparin infusion at a reduced rate
when appropriate.
Stop heparin infusion about 30 minutes prior to the end of the
procedure.
For citrate anticoagulation, use ACD-A at 1:15 to 1:25
dilution with blood.
Use calcium infusion if necessary.
Cardiac monitor.
Administer scheduled medications only at the end of the
session.
 Especially cyclophosphamide and azathioprine. Prednisone and
prednisolone are minimally removed by TPE and supplemental dosing
after TPE has been found to be unnecessary.
Provide catheter care per routine.
~ Thanks For Your Attention ~
~ 感謝聆聽,敬請指教 ~
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