Transfusion Flashcards

1
Q

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

A
  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
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2
Q

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

A

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

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3
Q

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

A
  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
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4
Q

Features of TA-GvHD

A
  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)

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5
Q

List 4 complications of massive transfusion (excluding transfusion reactions)

A
Hypocalcemia
Hyperkalemia
Acidosis
Dilutional coagulopathy/thrombocytopenia
Hypothermia (impairs platelets, decreases citrate metabolism, increases hemoglobin affinity, impairs myocardial function)
MO: development of allo-antibodies
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6
Q

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

A
  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
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7
Q
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
A

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

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8
Q

What are indications for rFVIIa

A

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

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9
Q

Post tranfusion purpura:

  1. Severity of thrombocytopenia:
  2. Onset and timing:
  3. Mechanism:
  4. Diagnosis:
  5. Treatment:
A
  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.
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10
Q

Potential side effects of IVIG

A
  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
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11
Q

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

A

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

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12
Q

5 most common antigens in delayed HTR

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

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)

A

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

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14
Q

What is the McLeod phenotype?

A

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!

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15
Q

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

A

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.

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16
Q

What are the components of cryoprecipitate?

A

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.

17
Q

Describe forward and reverse typing when testing for RBC antigens.

A

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

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

18
Q

3 examples of forward and reverse typing discrepancies

A
  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.
19
Q

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

A
  • 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
20
Q

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?

A
  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.
21
Q

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

A
  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).
22
Q

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

A

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!

23
Q

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

A

Postive for C3 and IgG.

24
Q

Most common cause of transfusion associated bacterial sepsis?

A

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

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

25
Q

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

A
  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)
26
Q

5 benefits of leukoreduction of RBCS?

A
  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
27
Q

Indications for irradiation of blood products?

A

●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

28
Q

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

A
  1. CMV
  2. EBV
  3. HTLV
  4. Yersinia (bacterial)
29
Q

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

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