ICM - Viva - Plasmapheresis Flashcards
What is the difference between plasmapheresis and plasma exchange
Pheresis - plasma is seperated from other blood components and plasma is removed without a replacement solution
Plas Ex - plasmapheresis follow by replacement with FFP or albumin
Processes involved in pheresis
Centrigugation
Filtration
Describe centrifugation
Seperates the blood in layers based on the major blood components based on their specific gravities
Adv - no limit to size of molecules removed
Disad - hard to do on ICU, usually by blood bank
Describe filtration
Utilises a semi-permeable membrane
Utilises differences in particle size to filter plasma from cellular components of bloods
Adv - can be do done on ICU
Disad - size of molecule removed depends on pore size
Catergories of indications for plasmaphoresis
i - first line therapy (primary or in combo) - GBS
ii - disorders where aphoresis is 2nd line - e.g acute disseminated encephalomyelitis after failure of steroids
iii - Optimum role of aphoresis not established - sepsis, MOF, thyroid storm
iv - apheresis would be harmful - Rh Arthritis
Indications for Plex
GBS ADEM MG MS Chronic inflam demylelinating polyradiculopathy
Renal: Granulomatosis Goodpastures Myeloma cast nephropathy Antibody mediated tranplant rejection
Haem
TTP
Atypic HUS
Sickle leading to stroke
Fulminant Wilsons
SLE
Catastropic APS
How much plasma is removed
30-40ml/kg (1 to 1.5 plasma volumes)
One Plex removes 66% of an intravasular component and two plasma volume exchage removes 85%
What replacement fluids
Isotonic 4.5 to 5% HAS
FFP is used to replace ADAMTS13 in TTP or to replace clotting factors
Complications to Plex
Line or procedure
Line Infection Misplacement PTx Bleeding Arrhytmia
Procedure Hypotension Hypothermia Transfusion reaction (FFP) Thrombocytopenia Hypofibrinogenaemia Hypocalcaemia
