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Book - Transfusion Medicine for Pathologists > Ch. 7 - Blood components (practices) > Flashcards

Ch. 7 - Blood components (practices) Flashcards

1
Q

What are the indications for red cell transfusion?

A

Generally, for patients with symptomatic deficiency in oxygen carrying capacity and/or inadequate circulating RBC mass.

Also, for prophylactic exchange in hemoglobinopathies and in neonates with HDFN.

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2
Q

In general, what are some transfusion thresholds for red cell units?

A

Transfuse for Hgb <7 and not for >10.

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3
Q

What were the findings of the TRICC trial?

A

Patients on a restrictive transfusion strategy (Hb 7 threshold) have similar outcomes to those on liberal transfusion strategy (Hb 10 threshold), with the exception of in ischemic heart disease.

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4
Q

In general, what is the expected impact of transfusion of one unit of RBCs in an adult?

A

Hgb should rise by 1g/dL, and Hct should rise by 3%.

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5
Q

What is the dosing of RBCs in children? What is the expeted effect?

A

10-15 mL/kg, which is expected to increase Hgb by 2-3 g/dL or Hct by 6%.

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6
Q

What measures may be taken if the presence of underlying alloantibodies cannot be determined?

A

Adsorption studies
Phenotyping
Genotyping

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7
Q

What is “emergency release” in the context of blood transfusion?

A

In these circumstances, an attending physician assumes responsibility for the emergent need for blood, under the assumption that the benefit of transfusion outweighs risk of incomplete serologic workup.

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8
Q

What is massive transfusion protocol (MTP)?

A

Release of blood components in a fixed regimen so as to reconstitute whole blood (eg. 1:1:1). These ratios should not be modified while the MTP is active.

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9
Q

What are some platelet transfusion triggers?

A

Any patient (prophylactic): <10k
Patients with coagulation disorders, anatomic lesions, or undergoing CVC placement: <20k
Patients iwth active bleeding, undergoing LP, or non-CNS surgery: <50k
Bleeding into confined spaces such as CNS, ophthalmic, pulmonary?: <100k

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10
Q

What are some conditions that can cause thrombocytopathy?

A

Inherited disorders: Bernard-Soulier, Glanzmann’s etc
Drug effect: Antiplatelet
Myelodysplastic syndrome
Surgical/cardiac bypass

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11
Q

What are some contraindications to platelet transfusion?

A

ITP
TTP
PTP
HIT

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12
Q

What is the expected impact of one pheresis platelet unit?

A

The platelet count is expected to increase by 30k-60k.

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13
Q

What is the advantage of single-donor platelet transfusion over “six-packs”?

A

Less alloimmunization risk (see: TRAP)
Less infectious risk
Less risk in special cases such as IgA deficiency or NAIT.

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14
Q

What is the role of ABO-matching in platelet tranfusion?

A

ABO-identical platelet units generally have better effect on raising platelet count, but incompatible transfusion is often acceptable. Consider volume reduction in sensitive cases (eg Pediatrics)

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15
Q

Describe the workup for platelet refractoriness.

A
  1. Rule out nonimmune causes (fever, sepsis, splenic sequestration, drugs, DIC/TTP)
  2. Perform corrected count increment (CCI) 1hr after transfusion.
  3. If refractory, perform HLA evaluations.
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16
Q

How is CCI calculated?

A

(Body surface area * [change in platelet count])/(number of platelets transfused)

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17
Q

What are the three treatment options for platelet refractory patients?

A
  1. HLA-matched platelets
  2. HLA-antigen negative units for patient’s known HLA antibodies
  3. Platelet crossmatch-compatible units
18
Q

Describe the grading of HLA-matching in platelets.

A

Match HLA-A and HLA-B, as follows:
A: Four antigens matched
BU: Three antigens identical, one unknown
B2U: Two antigens identical, two unknown
B1X: Three antigens identical, one CREG
B2UX: Two antigens identical, one unknown, one CREG
C, D: Mismatched antigens

19
Q

How should all HLA-matched platelets be treated?

A

All should be irradiated.

20
Q

How is Rh matching handled in platelet transfusion?

A

Try to provide Rh-negative platelets to Rh-negative women of childbearing age. Otherwise, transfuse with RhIG.

21
Q

How is platelet crossmatching performed?

A

Solid phase red cell adherence assay; mix recipient serum with donor platelets and indicator red cells.

22
Q

Name 5 indications for plasma transfusion.

A
  1. Active bleeding with multifactor deficiency
  2. Emergency reversal of warfarin-induced coagulopathy (with bleeding)
  3. Use as replacement fluid for TPE
  4. Patients with congenital factor deficiencies
  5. Hereditary angioedema (C1 esterase deficiency) **outdated
23
Q

What is the role of plasma in correcting INR abnormalities?

A

Mild abnormalities are not well-effected by plasma administration. INR moreover is a poor predictor of significant clinical bleeding.

24
Q

What is the typical dose and expected effect of plasma transfusion?

A

10-20mL/kg

Should increase all coagulation factors by 20% (give quickly!)

25
Q

Compare the utility of FFP, PF24, and PF24RT24.

A

All are clinically equivalent for treating multifactor deficiencies, but FFP should be used in patients with single factor deficiencies (eg fV deficiency)

26
Q

What are some (current and former) indications for cryoprecipitate?

A 
Fibrinogen deficiency (congenital or acquired)
Treatment of bleeding in uremia
von Willebrand disease (former)
Hemophilia A (former)
*also used as a topical fibrin sealant
27
Q

How is cryo dosed, and what is the expected impact in adults?

A

A dose of cryo is typically 10 units, and is expected to raise fibrinogen level by around 100mg/dL.

28
Q

How is cryo dosed in a pediatric population?

A

1-2 units per 10kg. Should still raise fibrinogen level by around 100mg/dL.

29
Q

How can the number of cryo units be calculated given a desired fibrinogen level?

A

(Change in fibrinogen level * plasma volume)/ 250mg (per unit).

30
Q

When should granulocytes be considered as a therapeutic option? 4 criteria.

A
  1. ANC < 500
  2. Bacterial or fungal infection for 24-48hrs
  3. No evidence of improvement with Abx
  4. Reasonable chance of future BM recovery
31
Q

What is a standard dose of granulocytes? How should the unit be treated?

A

1.0 x 10^10 granulocytes. ABO and CMV-match the donor. Irradiate!

32
Q

Compare and contrast albumin and plasma protein fractions.

A

Albumin: 96% albumin, 4% globulins. Prepared by cold alcohol fractionation and heat-inactivated.

Plasma protein fractions: 83% albumin, 17% globulins, less purified than albumin.

33
Q

What are the indications for albumin?

A 
Treatment of hypovolemia
Acutely hypoproteinemic patients
Burns
Replacement fluid for plasmapheresis
(not for nutritional correction!)
34
Q

Describe the two preparations of factor VIII concentrate.

A

Plasma-derived: Made by fractionating pooled plasma. Has some vWF, okay for treatment of vWD.

Recombinant: High purity, okay for treatment of hemophilia A

35
Q

What are the half-lives for concentrates of factors VIII, IX, X, and XIII? Fibrinogen?

A 
VIII: 8-12hrs
IX: 18-24hrs
X: 30hrs
XIII: 9d
Fibrinogen: 3d
36
Q

What is prothrombin complex concentrate (PCC)? aPCC?

A

A product of factor IX that also contains other vitK-dependent factors (II, X, and maybe VII). aPCC has activated factor VII. They can be used for severe bleeding and…various bleeding disorders.

37
Q

What is topical fibrin sealant?

A

A product containing fibrinogen and thrombin in separate containers, which is mixed to form a fibrin clot.

38
Q

What substances should never be infused with blood products?

A

Medications
Non-isotonic solutions (eg 5% dextrose)
Calcium-containing fluids (eg Lactated Ringer’s)

39
Q

What rate of transfusion should be observed for blood products?

A

Start slow, usually 1-2mL/min to observe reactions.
Transfuse 2mL/min for granulocytes, 4mL/min for RBCs, and 5mL/min for plasma products.
In any case, finish within 4hrs.

40
Q

In what contexts are blood warmers most useful?

A

During massive transfusion (trauma, surgery, apheresis), in newborns, and maybe in cold-agglutinin disease.

Book - Transfusion Medicine for Pathologists (13 decks)

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