1. Plasma Exchange
Chan King Chung

2. History Begins in the 1970s Initially to treat anti-GBM disease
Blood cell separators
Initially to treat anti-GBM disease
Lowering circulating antibody
Widespread use in different condition
Some indication replaced by other method
Selective extraction for hypercholesterolemia
IVIg for immunotherapy

3. Indications Removal of ‘evil’ humoral substances Antibodies
Goodpasture’s Syndrome (Anti-GBM)
Wegener Granulomatosis (ANCA)
Myasthensia Gravis (Anti-AChR)
Toxins
Triglycerides
Paraproteins
Thyroxin
Acetylsalicylate
Cytokines
Sepsis
Uncertain
Thrombotic Thrombocytopenic Purpura
Haemolytic Uraemic Syndrome
Guillain-Barre´ syndrome
Miller Fisher syndrome
Liver failure

4. Physiology of Body Fluid
ECF (27%)
19L
Plasma
(4 - 5%) 3L
Interstitial
(12%) 8L
RBC
(2 – 3.5%)
Non-water mass
ICF (33%)
23L
(40%)

5. Dosage Blood volume 7% of BW Plasma volume ~4% of BW (40mL/kg)
Residual plasma volume = e-(volume removed)
Change of 1 plasma volume = 37% remain

6. Dosage Usual 1-1.3x plasma volume per session
Volume = (1- Hct) x 70mL x BW x 1 or 1.3
~2 to 3L in most case

7. Dosage Frequency of Plasma Exchange depends on
Distribution of substance
Rate of production
~5 plasma volume in 7 to 10 days will remove ~90% of the plasma substance

8. Techniques of Plasma Exchange
Access: large vein ± dialysis catheter
Anticoagulation
Cell Separator
Centrifugation
Membrane plasma filtration
Replacement
Fresh frozen plasma
Albumin
Colloid / Crystalloid

9. Anticoagulation Heparin Citrate 2000 to 5000 units bolus then
500 to 2000 units/hour
Citrate

10. Cell Separator
Centrifugation
600mL in 37 mins
                        

11. Cell Separator
                                
Membrane filtration

12. Performance of Prisma TPE

13. Replacement Post-filter FFP Contain all component
Replacement of specific factor (TTP / Liver failure)
Risk of transfusion
Citrate Toxicity
? Giving back the ‘Evil’ humoral

14. Composition of Plasma Water Electrolytes Proteins
Na, Cl, Ca, K, PO4, Mg
Osmotic pressure of 5526 mmHg
Between ECF and ICF
Proteins
Albumin, Globulins, Complements, Transport Protein, etc.
Oncotic pressure of 25 mmHg
Distribution between plasma & interstitial fluid

15. Replacement Albumin Expensive Risk of hypokalemia and hypocalcaemia
Risk of bleeding
Risk of Prion diseases
Mixing electrolyte with 5% albumin solution before use (in paediatrics)

16. Albumin Replacement e- ECF (27%) 19L Plasma (4 - 5%) 3L Interstitial
RBC
(2 – 3.5%)
Non-water mass
ICF (33%)
23L
(40%) e-

18. Replacement Colloids HES / Gelofusin Cheaper compare with Albumin
Safer
Problem with oncotic pressure
Slowly loosing oncotic pressure -> hypovolaemia
Pulmonary edema
Problem with electrolyte / bleeding

19. Colloid Replacement ECF (27%) 19L Plasma (4 - 5%) 3L Interstitial
RBC
(2 – 3.5%)
Non-water mass
ICF (33%)
23L
(40%)
H20

20. Colloid Replacement Risk of hypovolaemia balanced by
Higher volume of replacement
Close monitoring
Risk of pulmonary edema is low
Normal oncotic pressure is ~25mmHg
Theoretical risk of pulmonary edema when oncotic pressure is <10mmHg

21. Colloid Replacement
Studies using HES (t1/2: 8hr) instead of albumin had demonstrated the safety of colloid
Journal of Clinical Apheresis. 12(3):146-53, 1997
Less data is available for using gelatin (e.g. gelofusine t1/2: 2hr)
Usually when Albumin > 30g/L

22. Replacement Crystalloid Crystalloid-only replacement is not used
Half crystalloid, half albumin regime is commonly used for saving money
~1/3 of crystalloid stay in intravascular space
Bolus of crystalloid may be given for hypotension

23. Typical Replacement Full volume gelatin Half gelatin then half albumin
Resulting Alb level 25g/dL
Half gelatin then half FFP
Full volume FFP
For TTP

24. Electrolyte Replacement
Hypokalemia might occur
3L plasma only contain mmol K
Large reserve inside the cells
Hypocalcaemia
3L plasma contain 6–7 mmol Ca
~10ml 10%CaCl2
Especially if
Total Albumin replacement (Ca mmol/L)
Cannot clear citrate (as anticoagulation / FFP / Albumin)

25. Setup 3L Session (3hr) Anticoagulation (ACDA 240mL/hr) Replacement
Blood
( mL/min)
Plasma (1L/hr)

30. Adverse Reaction Hypotension Hypovolaemia Hypocalcaemia
Allergic reaction
ACEI
Membrane activation
Prekallikrine activator in SPPF

31. Adverse Reaction Bleeding tendency Immunosuppression
Lowered coagulation factors in underlying bleeding disease (TTP)
Immunosuppression
Lost of immunoglobulins, complements

32. Modification of Plasma Exchange
Coupled Plasma Filtration Adsorption
Plasma Filter
Charcoal

33. How are we going to do ? By Haematology as much as possible Prisma TPE
AK10

34. Prisma TPE More correct monitoring of volume
Automatically stop removal pump when the replacement is empty
Safer
Unfamiliar
Higher cost

35. Prisma TPE Setting Haematocrit Blood flow rate
Replacement bottle volume
Replacement volume
Replacement rate
Net patient plasma removal rate
** Net plasma removal volume **

36. Prisma TPE 3L Session (3hr) Anticoagulation (ACDA 240mL/hr)
Replacement
(1L/hr)
Blood
( mL/min)
Plasma [1L/hr]+[0mL/hr]

37. ? Fluid Gain 240mL/hr for 3 hours 720mL over 3 hours
A small volume only. Can be handled by kidney
Useful to counter act hypotension
In theory, may set 80mL/hr net loss, as only 1/3 is in intravascular space

38. AK10 Cheaper and more familiar Same setup as CVVH
Only 1 replacement pump and 1 filtrate pump
Volume state less accurate than Prisma
Risk of hypovolaemia if the replacement pump stopped