Transfusion Medicine

Question 1

What determines blood type?

Answer 1

• The presence or absence of antigens on the RBC surface

Question 2

Is the first transfusion ‘free’ for dogs?

Answer 2

No
- If a patient negative for DEA is given positive blood for the first transfusion, a delayed reaction will occur from the sensitization of the immune system gradually increasing the anti DEA 1 antibody titer
- Mismatches always result in delayed hemolytic reactions and prime recipients for severe acute reactions upon second exposure

Question 3

Can Type A cats receive Type B blood?

Answer 3

• Technically yes but shouldn’t
• Their anti B antibodies are fairly weak in affinity and low in titer level so they cause a mild or delayed hemolytic reaction
• Transfused cells will only have a 1/2 life of 2 days

Question 4

Can Type B cats receive Type A blood?

Answer 4

• No
• Type B cats have very strong anti A alloantibodies and will have an acute and severe hemolytic reaction

Question 5

What blood can be given to a type AB cat?

Answer 5

• Both as they do not have any alloantibodies
• However, alloantibodies in plasma of type A & B blood may cause a reaction due to presence of anti A or anti BN antibodies
• Therefore type A is preferred as anti B antibodies occur at lower titer in type A blood - using pRBC minimizes amount of plasma containing anti B antibodies being transfused

Question 6

What does the MAJOR crossmatch check?

Answer 6

• Mixes PATIENT PLASMA with DONOR RBCs

Question 7

What does the MINOR crossmatch check?

Answer 7

• Mixes DONOR PLASMA with PATIENT RBCs

Question 8

A patient should be cross matched if they received a transfusion _____ ago

Answer 8

> 4 days

Question 9

What is a massive transfusion?

Answer 9

The replacement of blood approaching or exceeding one total BV within a 24 hour period

Question 10

What does stored whole blood NOT contain?

Answer 10

• Viable platelets
• Labile clotting factors: F V, VIII, vWf

Question 11

What does FFP contain?

Answer 11

• All labile (F V, VIII, vwf) and non labile clotting factors, plasma proteins, albumin, and globulins

Question 12

What does FFP not contain?

Answer 12

Platelets

Question 13

What does FP contain?

Answer 13

• non labile F II, VII, X, albumin, globulin
• Can be kept for 5 years

Question 14

What is cryoprecipitate?

Answer 14

• The precipitate of thawed FFP
• Contains vWf, FVIII, fibrinogen, FXIII
• These factors are found in FFP, but administering cryo allows the same result but with less volume
• Hemophilia A

Question 15

What is cryosupernatent?

Answer 15

-Supernatant that was produced during creation of cryo
- LACKS FVIII, FXIII, fibrinogen, vWf
- HAS albumin and remaining coag factors, including Vit K dependent factors
- Hemophilia B

Question 16

How does albumin play a role in coagulation?

Answer 16

• Regulates coagulation by mediating thromboxane A2 levels
• HypoA leads to increased TXA2 levels, contributing to a hypercoagulable state

Question 17

What are immunoglobulins used for?

Answer 17

• Used as an immunosuppresant in refractory immune mediated disease

Question 18

What is platelet rich plasma? (PRP)

Answer 18

• Platelets harvested from a unit of FWB that is less than 8 hours old and has not been cooled
• Room temp platelets maintain viability better than refrigerated ones
• Shelf life of 5 days and requires constant agitation

Question 19

Should plasma be type matched?

Answer 19

Yes, to prevent sensitization from RBCs they contain

Question 20

Does plasma need to be given with a filter?

Answer 20

Yes

Question 21

What are the four categories of reactions?

Answer 21

• Acute immunological
• Acute non immunological
• Delayed immunological
• Delayed non immunological

Question 22

What is an immunological reaction?

Answer 22

• Caused by antigen-antibody interactions between donor & recipient
• Antibodies present in recipient plasma recognise RBC antigens as foreign

Question 23

Is premedicating with antihistamines or steroids recommended?

Answer 23

• Only if there is a history of a reaction
• It will not prevent a reaction but may mask the early signs of one

Question 24

What is a WBC/platelet incompatibility reaction?

Answer 24

Occurs when antibodies form against donor WBC or platelet antigens

Question 25

What is anaphylaxis to a blood component?

Answer 25

An immunologic reaction mediated by IgE or IgG molecules found on mast cells

Question 26

What is TACO?

Answer 26

• Immunosuppression following blood component transfusion
• Immunological reaction

Question 27

What is TRIM?

Answer 27

• Transfusion-related immunomodulation
• Immunosuppression following blood component transfusion
• Serum sickness/Type III hypersensitivity reaction occurs weeks later
• Immunological reaction

Question 28

What is a non immunological reaction?

Answer 28

• Occurs from outside factors and are not directly related to RBC, platelets, or protein antigen-antibody reactions
• Most often occur from collection/storage/administration errors
• TACO

Question 29

What are storage lesions?

Answer 29

• Progressive, morphological, metabolic, biochemical changes that occur to RBC during storage
• These changes reduce the number of viable RBCs and make them less effective as oxygen carriers

Question 30

Does a filter need to be used when administering an auto transfusion?

Answer 30

Yes

Question 31

Do anticoagulants need to be added to auto transfusions before administration?

Answer 31

No, blood pooled in body cavities has typically consumed coagulation factors & undergone fibrinolysis

Question 32

Do cats have naturally occuring alloantibodies to DEA blood?

Answer 32

No, but the first exposure leads to sensitization and a delayed hemolysis that always occurs 4-7 days later