Transfusion Medicine Flashcards
TRIPICU study
RCT: Restrictive (<70) vs liberal transfusion (<95) with end point of MODS - no diff in end point - 54% not transfused in restrictive vs 2% for liberal *Note that in adults restrictive had improved mortality!
Plt threshold in HSCT study - Zumberg 2002
RCT: Restrictive (<10) vs liberal transfusion (<20) with end point of MODS - no diff in end point
what does cryo contain
FVIII, FXIII, vWF, fibrinogen Dosing 2-5 ml/kg
RING RCT of granulocytes vs Abx alone
Underpowered but no difference seen Post-hoc analysis shows that those with highest dose had benefit.
Components of cryo
Factor VIII FXIII Fibrinogen vWF Dose: 1U/10kg
IVIG indications
Hypogam ITP NAIT Humoral immunodeficiency Neuro - GBS, OMA Inflammatory - KD
Typical transfusion amount and expected rise for:
- RBC
- Plt
- FFP
PRBC: 15ml/kg/dose given over 2-4 hrs, expect rise of 20 g/L
Platelets: 10ml/kg, or one pool of platelets (usually 300 ml)l IV given over 60 mins, expect rise of 15-25x10^9 at 1 hr
FFP: 10-20ml/kg/dose IV over 30-120 mins. Half life of different coagulation factors: FVII: 3-6 hrs, FVIII: 8-12 hrs, FII: 2-3 days, FIX: 2-3 days. FP contains 400-900mg of fibrinogen per 250ml
IndicatAddions for erythrocytapharesis
- severe babesiosis
- severe malaria
- PV
- SCD: life/organ threatening
- SCD stroke prevention
- SCD iron overload prevention
Indications for plasmapharesis
- ABO incompatible HSCT
- ABO SOT
- TTP
- HUS
- Myasthenia gravis
- PANDAS
- Syndenham’s chorea
- BGS
- Chronic inflammatory demylinating neuropathy
- ANCA-associated vasculitis (Wegner’s)
Forward type A but anti-A and anti-B Ab on reverse typing. How is this possible?
Patient has A2 alleles so makes A1 antibodies
Strong cold antibodies that agglutinate all cells
Rouleaux
Forward type O but no anti-A or anti-B antibodies present
Newborn
Hypogamm
lab error
What is the bombay phenotype?
Lack functional H gene.
Forward and reverse type as O
Make anti-A, anti-B and anti-H antibodies.
Can only transfuse with blood from bombay phenotype
List three benefits of leukoreduction
Decreased rates of:
- febrile non hemolytic transfusion reactions
- HLA alloimmunization
- CMV associated
- reperfusion injury
What are the benefits of washing RBCs or Plts
Decreases the proteins in the plasma that can cause allergic reactions. Can be done to prevent recurrent anaphylaxis in patients with IgA deficiency and anti-IgA antibodies.
Lose 25% of cell product
List all the clinical indications in Canada for providing irradiated blood
- Indications for irradiation include:
- Intrauterine transfusion
- Premature infants
- Congenital immunodeficiency
- Those undergoing exchange transfusion for erythroblastosis
- Hematological malignancy or solid tumor
- Recipient of peripheral blood stem cells, marrow, cord blood or cytotoxic T lymphocytes
- Recipient of HLA matched products
- Lupus or any other condition requiring fludarabine, cyclophosphamide or combination myeloablative therapy
- Donor is a blood relative (directed donations)
- Potential indications include:
- Term infant (up to 4 months)
- Recipients of solid organ transplants
- Recipient and donor pair from a genetically homogenous population
- Other patients with hematological malignancy or solid tumor receiving immunosuppressive agents
What viruses are not destroyed by viral inactivation of blood
HepA and parvovirus
2 instances when there may be differences between forward and reverse typing
- Recent transfusion (especially massive transfusion)
- Medical condition that impairs antibody production - hematologic malignancy, B-cell immunodef
- ABO incompatible transplant
- Gram neg bacterial infection - removes the N-acetyl from the N-acetyl-galactosamine from group A, leaving only the terminal galactose to make it look like a B antigen on the surface of the cell (only forward typing)
List antigens typically involved in PCH, WAIHA, Cold agglutinin, SCDl
PCH: Anti-P antibodies
WAIHA: Common antigens: Rh, Kell
Cold agglutinin: anti-I if mycoplasma, anti-i if EBV, antiP also reported
SCD: majority of alloimmunization occurs to Rh and Kell
List reasons why patients may be refractory to platelet transfusions
Non-immune (2/3): infection/sepsis, fever (T>38.4), bleeding, splenomegaly, DIC, HSCT, hepatic veno-occlusive disease, GVHD, medications (vanco, amphotericin B, heparin)
Immune (1/3): alloimmunization to HLA (human leukocyte antigen) and/or HPA (human platelet-specific antigens), due to prior exposure via transfusion, pregnancy, or transplantation, ABO incompatibility may also play limited role
What are ways to prevent platelet refractory state
- Leukoreduction can decrease in the incidence of alloimmunization to HLA Class I antigens and subsequent platelet refractoriness
- Use of ABO compatible platelets is shown to reduce the frequency of platelet refractoriness
treatment for immune platelet refractoriness
- If HLA antibodies against platelets are identified, give:
- HLA-matched platelets - matched for HLA-A and HLA-B loci, platelets are not routinely matched for HLA-C antigen
- HLA-antigen negative “compatible” platelets - apheresis platelets that lack HLA antigens reacting specifically with the patient’s antibodies
- Crossmatch-compatible platelets - crossmatch the units of apheresis platelets with the patient’s plasma
- If HPA antibodies against platelets (rare) - crossmatching may be beneficial
- Give fresher platelets or ABO matched platelets
- Treat active bleeding aggressively
- Consider antifibrinolytic agents, IVIG +/- plasmapheresis, rituximab, recombinant human factor VIIa (off-label use)
- Splenectomy is not helpful
- Steroids are not helpful
Canadian donors tested for the following viruses:
HIV, HBV, HTLV, syphilis, HCV, WNV, bacteria (platelets cultured); selectively for CMV, trypanosoma cruzi (Chagas’ disease)
Directed donations
No difference in HIV, higher hepatitis rates
cannot use emergently
Must irradiate b/c TA-GVHD
Benefits of leukoreduction
Decreased CMV transmission
Decreased risk of alloimmunization
Decreased febrile transfusion reactions
