Transfusion Medicine Flashcards
what factor has the shortest half life?
factor VII
half life of factor VII?
6 hrs
how to reverse warfarin
PCC (FEIBA)
vitamin K (IV faster than PO)
plasma can be given if other options are not available
what is in PCCs
human-derived coagulation factor concentrates - contains factor 2, 7, 9 and 10, protein C and S
volume of one unit of cryo
10-15 mL
infusion time of cryo
15-30mins for total dose
sepsis occurs most frequently with which blood product and why
platelets, because they are stored at RT
what is TRALI
acute respiratory distress with hypoxia and bilateral chest infiltrates on x-ray - occurs within 6 hrs of transfusion
when can transfusion associated GVHD occur?
- immunocompromised recipient
- immunocompetent recipient transfused a haplo identical product
who should receive irradiated blood?
- Congenital immunodeficiency states
- Intrauterine and neonatal exchange transfusions
- Pre-term infants
- Patients with lymphoma
- Post-transplant (bone marrow or stem cell)
- Treatment with purine analogues (e.g. fludarabine)
- Directed donations from family members
- HLA-matched platelets
most common antigen causing anti-platelet antibodies post transfusion?
HPA-1a
most common viral infection transmitted by blood product in canada
west nile virus (< 1 in 1 million)
hepatitis B (1 in 1.7 million)
chagas (1 in 4 million)
components of cryoprecipitate
fibrinogen
factor 8
factor 13
vWF
what is the correlation between ABO antigen expression and VWF
people with blood type O have approx 25% less factor 8 and VWF
dosing of pRBCs and how much hemoglobin should increase
10-20 cc/kg (15 cc/kg) should increase hemoglobin by 10
dosing of platelets and how much count should increase
10 cc/kg should increase platelets by 50-100
FFP dosing and how much coagulation factors should increase
10-15 cc/kg should increase coagulation factors 15-20%
dosing of cryo and how much fibrinogen should increase
1 unit/10kg should increase fibrinogen by 0.5
which viruses are destroyed by viral inactivation?
encapsulated viruses (inactivation affects lipid membrane) such as HIV, hep B/C, HTLV, EBV, CMV
at what age do isohemagglutinins develop?
usually between 4-8 months
altho small amounts can be detected at birth
what is a type and screen
determines the person’s ABO blood group, Rh status and screens for antibodies against minor antigens
what is a cross match
mixing of the person’s serum with the washed RBCs that they were matched with to ensure they do not agglutinate
most common blood type?
O (approx 46% in canada)
least common blood type?
bombay (no AB or H antigen, <1%)
followed by AB (approx 3%)
common clinical scenarios that can have a positive DAT (name 3)
delayed hemolytic transfusion reaction
AIHA
HDFN
what is the indirect antiglobulin test?
the patient’s serum is incubated with RBCs that are known to express a certain antigen on their cell surface, then incubated with anti-human globulin - observed to see if they agglutinate (used to screen pregnant women for antibodies that can cause HDFN)
patient has anaphylaxis to blood products. how do you investigate IgA deficiency?
IgA level
anti-IgA antibodies
special prep for platelets in patient with anaphylaxis related to IgA deficiency
apheresis platelets from IgA deficient donor
special prep for RBCs in patient with anaphylaxis related to IgA deficiency
wash to reduce IgA levels significantly
two uses of PCC
- to reverse warfarin-related bleeding
- to treat bleeding in hemophilia B if purified factor is not available
when would you use activated PCC (FEIBA)
in patient with hemophilia A and inhibitor who is bleeding
how common is selective IgA deficiency?
range from 1/100 to 1/1000 (in canada, less common in asians)
components of whole blood
RBC
plasma
buffy coat (which contains platelets)
storage limit of platelets
5 days
which antigens are important in SCD population
Rh and Kell
what is the formula used to identify patients who are refractory to platelet transfusions
Correct count increments = platelet count increase x BSA x 10^11 / total platelet transfused
how can you prevent platelet refractoriness?
use ABO compatible platelets
treatment of platelet refractoriness
try using HLA matched platelets, crossmatch the platelets, give fresh platelets, ABO matched platelets
cause of febrile transfusion reaction
cytokines that are generated / accumulated during storage of blood products
three benefits of leukoreduction
- transmission of CMV
- alloimmunization of HLA antigens
- prevent febrile transfusion reactions
what products are leukoreduced?
RBC and platelets
why is blood irradiated?
to prevent transfusion associated GVHD
what products are irradiated?
RBCs
platelets
granulocytes
non-frozen fresh plasma
indication for CMV negative blood
patients receiving intrauterine transfusion
indications for cryopreservation of RBCs
rare blood types (ie bombay phenotype)
when evaluating an antibody panel, which antibodies have a dosage effect? (ie, if the antigen is heterozygous, it may be a false negative)
Rh (other than D)
Kidd
Duffy
MNS
("R you KidDing Me?")
