42 and 43 - Blood Products Flashcards
1
Q
What is forward typing?
A
Forward typing tests for antigens on the patient’s cells
ANTIGENS
2
Q
What is backward typing?
A
Backward typing tests for antibodies in the patient’s serum
ANTIBODIES
3
Q
What is a Direct Coombs testing?
A
- Tests for autoimmune hemolytic reactions
- Remember, if RBCs have an Antigen, the serum usually does not have a corresponding antibody. But when it does, antibodies bind the RBC leading to destruction of the cell
- Patient blood samples contain RBCs with antibodies attached to the cells
4
Q
What else do we call a direct Coombs test?
A
AKA Direct Antiglobulin Test (DAT)
5
Q
What does a direct Coombs test look for again?
A
Tests for antibody mediated hemolysis
6
Q
Describe the process of Coombs testing
A
- Antibodies are bound to red blood cells activate complement and result in cell lysis
- Wash the patient’s RBCs and expose them to Coombs reagent
- If antibodies are bound to the RBCs the Coombs reagent will bind those antibodies and lead to agglutination
7
Q
What is the naturallly occurring anti-globulin do we test for in rheumatologic disease?
A
Rheumatoid factor
- The Rh group alone has 50 different antigens
- We only care about three (ABO, Rh-D, Bombay)
8
Q
Describe ABO antigen
A
If you do not have an antigen, you are prone to forming antibodies against it
9
Q
What are the ABO blood types?
A
- A
- B
- AB
- O
10
Q
What are the genotypes for A?
A
AA
AO
OA
11
Q
What are the genotypes for B?
A
BB
BO
OB
12
Q
What are the genotypes for AB?
A
AB
BA
13
Q
What are the genotypes for O?
A
OO
14
Q
What are the antigens and antibodies for A?
A
Antigen A
Anti-B antibody
15
Q
What are the antigens and antibodies for B?
A
Antigen B
Anti-A antibody
16
Q
What are the antigens and antibodies for AB?
A
Both antigen A and B
Neither anti-A or anti-B
17
Q
What are the antigens and antibodies for O?
A
Neither antigen A or B
Both anti-A and anti-B
18
Q
How do you do ABO matching in a pinch?
A
- Type O are universal donors of RBCs
- No A or B antigen on donor cells for recipient antibody to attack
19
Q
What blood type are universal donors of plasma?
A
- Type AB are universal donors of plasma
- No anti-A or anti-B antibody present to attack recipient RBC antigen
20
Q
What is the Bombay phenotype?
A
- Type O blood is not truly “naked” of antigens
- Most ABO blood displays H antigen
- Hh blood typing
Capital H indicates patient has the antigen
Lower case h indicates patient lacks antigen - Type O blood of the Bombay Phenotype lacks H antigen (h/h genotype)
- Type O blood without H antigen will have anti-H antibodies in the serum
- Bombay phenotype patients have to receive blood from other Bombay phenotype patients
21
Q
What is the significance of RhD in terms of fetomaternal hemorrhage?
A
Significance of Fetomaternal Hemorrhage (FMH)
- If mom is RhD antigen negative and she is exposed to RhD antigen positive blood, she may form anti-RhD antibodies
- Maternal anti-RhD antibodies can cross the placenta and attack red blood cells of the fetus
- This results in higher risk of fetal demise, newborn death, and newborn hemolysis
- A patient with anti-RhD antibodies given RhD positive blood may have a delayed transfusion reaction
22
Q
Discuss the special processing of RBCs that have been donated - Leukocyte reduction
A
Leukocyte reduction
- Performed by filtration
- Vast majority of US blood supply is leukoreduced
- Reduces risk of CMV transmission in Bone Marrow Transplant patients***
- Does NOT prevent Transfusion Associated Graft Versus Host Disease
23
Q
Discuss the special processing of RBCs that have been donated - Washing
A
Washing
- Washed in normal saline
- Removes extra plasma and associated antibodies
- Decreases risk of anaphylactoid reaction, particularly in IgA deficient patients***
- IgA deficient patients have anti-IgA antibodies
24
Q
What is a “transfusion trigger” in terms of RBC transfusion in hemodynamically stable, surgical or ICU patient?
A
- Hgb
25
What is a "transfusion trigger" in terms of RBC transfusion in patients with active bleeding?
***
Hgb
26
What is a "transfusion trigger" in terms of RBC transfusion in patients with active cardiovascular disease?
***
Hgb
27
What is a "transfusion trigger" in terms of a GENERAL GOAL?
***
General goal in most patients is to keep hemoglobin 7.0-9.0
Some say 7.0-10.0
Pushing higher may increase mortality
28
What are special cases that change the "transfusion trigger"?
***
- Bleeding esophageal varices
| - Sickle cell disease
29
Describe why bleeding esophageal varices change the goal for Hb?
***
- Keep the patient as close to Hgb 8.0 as possible
- Less may impair oxygen delivery
- More may lead to high intravascular pressure and worsen the bleed!
30
Describe why sickle cell disease changes the goal for Hb?
***
- Beyond the scope of this lecture!
- They strongly suggest phoning your friendly hematologist for co-management!
- Around 7-8
- JUST KNOW CALL A HEMATOLOGIST ***
31
What is "type and screen"?
***
- Screens patient’s blood.
- Does NOT prepare donor blood
When you order this, you will know what antigens the patient has, but you don't have any blood ready
32
What is "type and cross"?
***
- Screens patient’s blood
- Cross matches donor blood for patient use
When you order this, you will have the blood product ready
33
What is pooled platelets?
Whole blood goes through a series of centrifuges to retrieve platelets along with a small amount of plasma.
Single donor platelets are obtained by apheresis
(More expensive, slightly lower transmission of infection)
34
What are contraindications for platelet transfusion?
***
- Heparin induced thrombocytopenia
| - Thrombotic thrombocytopenic purpura/hemolytic uremic syndrome
35
Why don't you want to give platelets to a patient with heparin induced thrombocytopenia?
***
Increased rate of thrombosis
You are already attacking your platelets via antibodies, this just increases the risk of
36
Why don't you want to give platelets to a patient with thrombotic thrombocytopenic purpura/Hemolytic uremic syndrome?
***
Accelerates the disease process
37
What is one possibility when you give a transfusion?
INFECTION
*** Transfusion-related infection ***
38
What type of infection is possible with a blood transfusion?
***
- HIV
- HCV
- HBV
- West Nile
- CMV
- Parasitic disease (malaria, chagas, babeiosis)
- Bacterial infection (MOST common *** - 1 in 2-3,000) and most common in PLATELETS ***
***KNOW platelet bacterial infection - test question??
39
What are some adverse reactions that can occur when giving a transfusion?
- Allergic reaction
- Anaphylactoid/anaphylactic reaction
- Febrile non-hemolytic transfusion reactions (febrile non-HTR)
- Delayed hemolytic transfusion reaction (DHTR)
- Acute hemolytic transfusion reaction (AHTR)
- Transfusion associated circulatory overload (TACO) ***
- Transfusion related acute lung injury (TRALI)
40
Describe allergic reactions
***
Allergic reaction
- Preformed antibodies to donor plasma proteins
- Urticaria, pruritus, flushing, mild wheezing
- Give antihistamines
- Not typically dangerous, if symptoms resolve may complete transfusion
41
Describe anaphylactoid/anaphylactic reactions
***
Anaphylactoid/Anaphylactic reaction
- Antibody to donor plasma proteins
- Hypotension, urticarial, bronchospasm, angioedema
- Rule out hemolysis
- Give epinephrine IM, antihistamines, and corticosteroids
- Intubate if necessary
- Minimize future transfusion risk with washed products
- Check patient for IgA deficiency
KNOW IM *** --> Giving epinephrine IV is good at bringing up BP, but does NOTHING for the anaphylaxis... NEED IM ***
42
Describe febrile non-hemolytic transfusion reactions (febrile non-HTR)
***
Febrile non-hemolytic transfusion reactions (febrile non-HTR)
- Due to preformed anti-WBC antibodies in the patient
- Temperature rises >1 degree Celsius in first 1-2 hours of transfusion
- Not typically dangerous. If no other symptoms you may resume transfusion
- Give acetaminophen
- Minimize recurrence by giving pre-transfusion acetaminophen
- Minimize recurrence by using leukocyte reduced blood products
43
Describe delayed hemolytic transfusion reaction (DHTR)
***
Delayed hemolytic transfusion reaction (DHTR)
- Occurs 1-2 weeks after transfusion
- Fever, jaundice, falling hgb
- Repeat type and screen to look for new antibody formation
- Repeat transfusion as needed with new type and screen
44
Describe acute hemolytic transfusion reaction (AHTR)
***
Acute Hemolytic Transfusion Reaction (AHTR)
- Preformed antibodies incompatible attack donor product antigen
- Chills, fever, hypotension,back pain, DIC
- Aggressively treat with IV fluids
- Use pressors if needed (norepinephrine is usually preferred)
- Keep urine output >1 ml/kg
- Fatality rate: 1 in 1,800,000 units transfused
45
Describe transfusion associated circulatory overload (TACO)
***
Hydrostatic fluid overload
- Essentially decompensated congestive heart failure caused by transfusion
- Dyspnea, tachypnea, jugular venous distention
- New or worsening peripheral edema
- Prevent with slow transfusion rates (1ml/kg/hr)
- Treat with diuretics
The basic idea is that they have too much fluid, not too complicated, just give diuretics
46
Describe transfusion related acute lung injury (TRALI)
***
Transfusion related acute lung injury (TRALI)
- Massive capillary leak in the pulmonary vasculature (Both antibody and non-antibody mediated mechanisms)
- Hypoxemia, transient leucopenia, bilateral pulmonary edema
- Occurs within 6 hours of transfusion
- Occurrence (1 in 5000 units PRBC, 1 in 2000 units Plasma, 1 in 432 units of whole blood)
- 5-20% mortality depending on which source your review
This one gets a lot of press in the medical community - Just comes up looking like ARDS (acute respiratory distress syndrome)
