Transfusion Medicine

Question 1

What is used as an anticoagulant for donated blood? How does it work?

Answer 1

citrate

chelates Ca

Question 2

packed RBCs

Answer 2

Use: increase O2 carrying capacity: anemia
Prep: differential centrifugation
250 ml/unit
1 unit increases Hgb 1g/dL: need more for hypotensive and less for CHF
Store: refrigerated 42 days
ABO compatibility required

Question 3

How many packed RBCs stored will lyse within 24 hours after transfusion?

Answer 3

up to 25%

Question 4

How are leukocytes removed from packed RBCs?

Answer 4

leukoreduced prbcs

irradiated prcbs

Question 5

plasma (FFP)

Answer 5

Use: replace clotting factors (factor VIII or IX, AT3, AdamTS13)
Prep: differential centrifugation
200-250 ml/unit: 1 unit increases clotting factors by 20%
Store: -20
ABO compatibility required (donor has Ab rather than recipient)
first choice treatment ONLY in TTP (AdamTS13)

Question 6

cyroprecipitate

Answer 6

proteins that precipitate our of plasma at 4 degrees
Use: replace fibrinogen, factor VIII, XIII, vWF
15 ml/unit: raise fibrinogen by 5-10mg/dL
Store: -20
does NOT have to be ABO compatible
use when plasma infusion would cause volume overload in patient

Question 7

platelets

Answer 7

Use: stop bleeding in thrombocytopenia, rarely to prevent bleeding in VERY low platelet count
- platelet count < 10K/ul
- patients that have undergone cardiopulmonary bypass or have been treated with aspirin
become less responsive after 5-10 transfusions
Prep: plasmapheresis (usually) or differential centrifugation
300 ml/unit: 1 unit increase platelets by 25K/ul
Store: room temp. 4-5 days
CANNOT refrigerate
does NOT have to be ABO compatible although it is ideal (incompatible don’t last as long)
Must have ABO compatible in low blood volume (neonates)

Question 8

normal platelet count

Answer 8

150-450K/ ul

Question 9

When are platelet transfusions ordered?

Answer 9

patient has low platelet count AND is bleeding

Question 10

What is the objective of red cell transfusion?

Answer 10

increase patient’s oxygen carrying capacity

ONLY reason outside of massive trauma

Question 11

indications for red cell transfusion

Answer 11

1. patient is symptomatic: increased HR and RR, confusion, weakness, dizziness (otherwise healthy patients can tolerate Hgb t reverse yet
   usually lab numbers do NOT indicate transfusion

Question 12

How do you treat hypotensive patients?

Answer 12

isotonic IV fluids

NOT blood

Question 13

How long does it take to get O- blood, type specific blood, and typed/screened/crossmatched blood?

Answer 13

O-: immediately
Type specific: 20 min
Typed/screened/crossmatched: another 20 minutes

Question 14

risks in RBC transfusion

Answer 14

1. immune response
2. volume overload
3. transfusion transmitted infection
4. graft versus host

Question 15

Immune responses to red blood cell transfusion

Answer 15

1. acute hemolytic reaction
2. production of An to a minor RBC antigen
3. urticarial reaction to transfused plasma proteins (RBC mostly plasma free: can cause urticaria anaphylaxis)
4. febrile reaction to transfused leukocytes

Question 16

presentation of acute hemolytic reaction to blood transfusion

Answer 16

most likely: fever, chills, chest pain, hypotension, less likely: nausea, flushing, dyspnea, hemoglobinuria
possible outcomes: renal failure, death

Question 17

What Ab must be crossmatched for sickle cell patients?

Answer 17

ABO, Rh, Kell (K)