Hematologic System Flashcards
How are RBCs processed to reduce the chance of febrile transfusion reactions and alloimmunization?
leukoreduction
Why should sodium bicarbonate be given to treat an acute transfusion reaction due to ABO incompatibility?
to alkalinize the urine and prevent hemoglobin precipitation in the renal tubules
What alternative anticoagulants can be used in a patient with HIT? Which are better in patients with renal and/or hepatic failure?
fondaparinux - renal metabolism
argatroban - hepatic metabolism
bivalirudin
What is Humate-P?
factor VIII and vWF concentrate
Which drugs can cause a positive Coombs test (drug-induced hemolysis)?
penicillin
2nd and 3rd generation cephalosporins
alpha methyldopa
procainamide
How do you determine the volume of RBCs to transfuse to reach a target hct?
RBC volume = (Hctinitial - Hcttarget) x BV
HctRBC
BV: blood volume
HctRBC: 60% or 0.6
How are RBCs processed to reduce the chance of GVHD?
irradiation
Is activation of the extrinsic or intrinsic pathway usually the initiating step for fibrin formation?
extrinsic pathway
How much factor VIII activity is needed prior to surgery?
50% for minor surgery
100% for major surgery
Which factors are exposed/released upon platelet activation?
GP IIb/IIIa receptors are exposed on the platelet surface
Thromboxane A2 and platelet activating factor (PAF) are released
What is the “two-hit” hypothesis of TRALI?
hit 1: sequestration of neutrophils in the lung (causing transient leukopenia)
hit 2: activation of reipient neutrophils by donor antibodies
How can factor VIII levels be increased in a patient with hemophilia A?
Factor VIII concentrate: 40 u/mL
cryoprecipitate: 5-10 u/mL
FFP: 1 u/mL
ddAVP: increase production to 2-4x baseline levels
What is the target of the antibodies that cause HIT?
hepain – platelet GP 1b complexes
*causes thrombosis, platelet consumption, and thrombocytopenia
Which anticoagulant is recommended for patients with HIT who need CPB?
bivalirudin
What is the risk of infection due to blood transfusion for HIV? HepB? HepC?
HIV and HepC: 1 in 2,000,000
HepB: 1 in 200,000
What is the mechanism of febrile transfusion reactions?
recipient antibodies directed against donor leukocytes