Transfusion

Question 1

Reasons to warrant Rho gam (other than 28 week dose)

Answer 1

1. Procedures (amniocentesis)
2. Abortion (spontaneous or induced)
3. Accidental transfusion of Rh+ blood
4. Blunt abdominal trauma
5. Ectopic pregnancy
6. Threatened pregnancy
7. Molar pregnancy
8. Fetal demise in T2/T3
9. Antipartum hemorrahge in T2/T3

Question 2

How much blood will a standard (300mg) vial of rhogam work for?

Answer 2

15mL rh + RBC (30mL fetal D+ whole blood)

Question 3

Blood screening for pathogens - Name 6 pathogens and the screening test used for each

Answer 3

1. HIV 1/2 – PCR/NAAT +serology
2. HCV – PCR/NAAT +sAg, cAb
3. HBV – PCR/NAAT +serology
4. HTLV-I/II – Serology
5. WNV – PCR/NAAT (seasonal)
6. Chagas disease if RF’s- Ab testing
7. Syphilis- Serology
8. Bacterial culture- platelets only
9. Plasma for fractionation- parvo B19

• don’t test for CMV as eliminated with leukoreduction
• ? Test for Zika

Question 4

Features of TA-GvHD

Answer 4

1. Pancytopenia
2. Diarrhea
3. Rash
4. Elevated liver enzymes
5. Mucositis
6. Fever

Donor lymphocytes attack recipient antigen-presenting tissue (skin, GI, liver, bone marrow) in a immunocompromised recipient who can’t stop donor lymphocyte engraftment, or if there is partial HLA match between donor and recipient (recipient’s cells don’t recognize donor as foreign, but donor cells do)

Question 5

List 4 complications of massive transfusion (excluding transfusion reactions)

Answer 5

Hypocalcemia
Hyperkalemia
Acidosis
Dilutional coagulopathy/thrombocytopenia
Hypothermia (impairs platelets, decreases citrate metabolism, increases hemoglobin affinity, impairs myocardial function)
MO: development of allo-antibodies

Question 6

If you irradiate RBC, what are two impacts on the red cell product?

Answer 6

1. Decreased life span/shelf life of RBCs (28 days) but not plts. Give within 14 days of irradiating.
2. Hemolysis leading to hyperkalemia, free hemoglobin

Question 7

TITrE2 Trial, NEJM 2015:trial in CV surgery assessing the benefits of a restrictive (Hb < 75) vs liberal (Hb < 90) transfusion strategy. For the following outcomes, state whether liberal or restrictive strategies are superior, or if neither is.
Infection risk 
Cardiac events 
ICU length of stay 
30 day mortality 
90 day mortality 
Myocardial infarction

Answer 7

Infection risk - no difference
Cardiac events - no difference
ICU length of stay no difference
30 day mortality- increased w restrictive
90 day mortality- increased w restrictive
Myocardial infarction- no difference

In CV surgery population, restrictive strategy was not superior to liberal strategy, and did have increased mortality

Question 8

What are indications for rFVIIa

Answer 8

Hemophilia A or B with inhibitors
Patients with acquired hemophilia
Congenital factor VII deficiency
Glanzmann thrombasthenia with platelet refractoriness.

Question 9

Post tranfusion purpura:

1. Severity of thrombocytopenia:
2. Onset and timing:
3. Mechanism:
4. Diagnosis:
5. Treatment:

Answer 9

1. Severity of thrombocytopenia: plt can be <20
2. Onset and recovery: if caused by alloab to the transfused plts, the onset 5 to 10 days + lasts for days-weeks. If caused by passive transfer of an antiplatelet Ab, onset is within hours, and recovery is within days.
3. Mechanism: i) Formation of immune complexes, adsorption of soluble platelet antigens onto autologous platelets; or
   ii) induction of platelet autoantibodies.
4. Diagnosis:detecting circulating alloAb to a common platelet antigen, most often HPA-1a (and lack of this antigen on pts plts)
5. Treatment: IVIG (rarely steroids but take 1-2 wks to work). If pt HPA1a neg, then give HPA1a neg plt for future transfusions.

Question 10

Potential side effects of IVIG

Answer 10

1. Infusion reactions with fever, rigors, headache
2. Aseptic meningitis
3. Renal complications with certain brands
4. hemolytic anemia
5. neutropenia
6. VTE
   Rare: anaphylaxis, bacterial sepsis

Question 11

What is the factor that distinguishes 4 factor PCC from 3 factor PCC?

Answer 11

4-factor PCCs containing all vitamin K–dependent coagulation factors, and as 3-factor PCCs, which contain relatively low concentrations of factor VII

Question 12

5 most common antigens in delayed HTR

Answer 12

Rh (34%),
Kidd (30%),
Duffy (14%),
Kell (13%), 
Ss >>MN (4%) antigen systems

Question 13

What isotype of immunoglobulins are the isohemaggultinins which healthy individuals produce against antigens not on their RBC surface? (ie. O individuals, produce what type of ABO immuoglobulins)

Answer 13

IgM antibodies!

Interestingly, O individuals produce an IgG anti-AB which cross reacts with both anti-A and anti-B and can cross the placenta which is why O mothers are more commonly implicated in HDFN. (IgM Abs, anti-A and anti-B cannot cross the placenta).

Rh, kell, kidd, duffy, MN are IgGs

Question 14

What is the McLeod phenotype?

Answer 14

Defect in XK locus resulting in low or absent expression of the erythrocyte blood group Kell antigens, Kell(-).

RBCs are acanthocytic with decreased deformability and reduced survival, leading to a chronic but often well-compensated hemolysis.

*Must receive kell negative transfusions!

Question 15

What is the formula for “corrected count increment (CCI)” used to measure platelet refractoriness?

Answer 15

CCI = body surface area (BSA; m2) × platelet count increment*10`11/number of platelets transfused.

Ex. 3 × 1011 platelets are Tx'd to a pt with a BSA of 1.8 m2, and the postTx increase in plt count is 23,000/μL, then the CCI =1.8 m2 × 23,000/μL / 1011/3 × 1011 = 13,800.

Plt refractoriness is defined as 2 or more consecutive postinfusion CCIs of < 5,000 to 7,500.

Question 16

What are the components of cryoprecipitate?

Answer 16

fibrinogen, factor VIII,VWF, factor XIII, and fibronectin.

Does not contain protein C or protein S.

Multiple units (8-10) are required to replete fibrinogen and cryo is not pathogen inactivated so infxn risk is high.

Question 17

Describe forward and reverse typing when testing for RBC antigens.

Answer 17

Forward typing- Pts RBCs mixed with Anti-A or Anti- B sera

Reverse typing- Stock A or B RBCs mixed with pt sera

Question 18

3 examples of forward and reverse typing discrepancies

Answer 18

1. Previously transfused pt (forward typing may be mixed)
2. neonate (only do forward typing, may not have developed isohemaggtinins yet)
3. Post HSCT (until complete engraftment)
4. Rare acquired phenotypes.

Question 19

What type of RBCs are chosen for intrauterine transfusions? What special processing do they undergo?

Answer 19

• fresh (<5 days)
• O-negative unit
• leukoreduced or from a CMV-seronegative donor
• negative for any offending antigen
• crossmatched against maternal serum
• irradiated
• hemoglobin S negative
• washed and concentrated

Question 20

Pt with AIHA who requires a pRBC transfusion. BB detects a panaggultinin. What steps can you suggest to ensure there is no alloantibody that may lead to a transfusion reaction?

Answer 20

1. ABCs, if pt needs blood urgently, release least incompatible units. If pheno is known–>pheno matched, least incompatible units.
2. Ask about transfusion, pregnancy and HSCT hx. If no prior sensitizing events, no chance of alloAb formation.
3. If prior sensitizing events, need to do extending RBC typing using DNA method (serologic testing will be confounded by the positive DAT)
4. Can use adsorption (more time consuming), where pt plasma and pt RBC are repetitively incubated to remove autoIg (stick to RBCs) and then plasma (presumably containing alloAb) is incubated with panel of RBC to determine alloAb. Will not work if pt is recently transfused! (the alloAb in question could be binding to the transfused RBCs). So…
5. Can use differential adsorption–>adsorbing aliquots of pt serum against RBCs of defined phenotypes to produce several adsorbed sera that give differential reactivity.

Question 21

What are two reasons that pts with SCD develop alloimmunization more than non-SCD pts with similar transfusion frequency?

Answer 21

1. African pts usually have rare phenotypes and are exposed to a predominately caucasian donor pool (higher rates of mismatch)
2. More immune responsive especially during times of inflammation or infection (more likely to develop Abs when hospitalized for ACS for ex).

Question 22

Hyperhemolysis in SCD, is the DAT positive or negative?When does it occur following transfusion?

Answer 22

Negative DAT
7-10 days after transfusion (Hct lower than before Tx)
Avoid future transfusions if possible
Always include on DDx for SCD pt with rising hemolytic markers, fever, pain!

Question 23

Acute hemolytic transfusion reaction from ABO incompatibility. What is the DAT pattern

Answer 23

Postive for C3 and IgG.

Question 24

Most common cause of transfusion associated bacterial sepsis?

Answer 24

Usually gram negatives, especially Yersinia enterocolitica because it survives refrigeration.

(gram positive are the most common contaminants but usually do not lead to sepsis).

Question 25

7 strategies to avoid the need for transfusion of blood products, pre and peri-operative?

Answer 25

1. Iron replacement, folate, vitamin B12 2. EPO 3. Limiting necessary blood draws 4. Limiting blood draw volume (pediatric tube collection) 5. Autologous transfusion (technically blood product) 6. Directed donation from family members (discouraged as may develop allo-Abs which could eliminate potential family donor in the event of needing SCT) 7. Cell salvage- blood suctioned into collection vessel, washed and re-transfused to pt. 8. Acute normovolemic hemodilution (ANH)- at start of OR, collect 1 unit of blood-->replace with NS so hemodynamics maintained--->start case, blood loss is dilute, less RBC mass loss---> end of case, re-transfuse collected unit (RBC mass, plt, clotting factors etc maintained). 9. Bloodless products (not approved, increased MI and stroke risk, still in clinical trials)

Question 26

5 benefits of leukoreduction of RBCS?

Answer 26

1. Prevention of febrile nonhemolytic transfusion reactions. 2. Prevention of CMV transmission 3. Prevention of alloimmunization to foreign HLA antigens. 4. Prevention of Yersinia enterocolitica 5. Prevention of EBV 6. Can reduce but not prevent HTLV1

Question 27

Indications for irradiation of blood products?

Answer 27

●Recipients of intrauterine or neonatal exchange transfusion; premature neonates ●Individuals with congenital cell-mediated immunodeficiency states ●Individuals treated with specific types of potent immunosuppressive therapies (purine analogs, ATG, certain monoclonal antibodies); this may include those being treated for NHL ●Recipients of hematopoietic stem cell transplant (autologous or allogeneic) ●Individuals with Hodgkin lymphoma (any stage of disease) ●Individuals at risk for partial HLA matching with the donor due to directed donations, HLA-matched products, or genetically homogeneous populations

Question 28

Name 4 infectious agents whose transmission is greatly reduced by universal leukoreduction.

Answer 28

1. CMV 2. EBV 3. HTLV 4. Yersinia (bacterial)

Question 29

Name THREE patient characteristics that are contraindications in use of WinRho in ITP treatment.

Answer 29

``` Rh negative patients Previous splenectomy Anaphylaxis to immune globulins IgA deficiency History of AIHA at high risk of anaphylaxis ```