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Heme - Strom > Transfusion Medicine > Flashcards

Transfusion Medicine Flashcards

1
Q

What is the most common blood product you will need?
• What does it consist of?
• How much is in a unit, and how much does it increase Hgb?

A

Most Common:
• Packed Red Blood Cells

Consist of:
• Only RBCs that have been spun down to remove plasma and platelets

How Much:
• 250 ml per unit, this increases Hgb by ~1g/dL

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2
Q

How long can you store Packed RBCs?

• why has this time period been chosen?

A

42 days = storage time

• Only up to 25% of transfused RBCs will lyse within 24 hours of transfusion

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3
Q

T or F: most hospitals outside of military hospitals and the VA use leukoreduced packed RBCs.

A

True, this is because there is little evidence supporting that it makes any difference

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4
Q

Why is Plasma typically given to patients?
• Unit size?
• Compatibility?

A

Typically Given to patients with Clotting issues

Unit Size:
• 200-250 ml

Compatibility:
• MUST BE ABO MATCHED (all donor Abs are present)

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5
Q

What is cryoprecipitate?

• Why would you use it instead of plasma?

A

Cryoprecipitate:
• Proteins that precipitate out of plasma at 4˚

Why use it:
• Improves clotting by providing clotting proteins without the risk of VOLUME overload

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6
Q

What clotting proteins is cyroprecipitate used to replace?
• size of unit
• Compatibility

A 
Proteins: 
• Fibrinogen
• Factor VIII
• Factor XIII
• vWF

Size of Unit:
• 15 mL (much smaller than 200-250 for plasma)

Does NOT have to be ABO compatible

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7
Q

When are platelets most commonly used?

• How are they prepared?

A

To stop bleeding in a patient that has a low platelet count (BELOW 50 K/µL)

**Less frequenty use for pts. at risk of spontaneous bleeding (platelets below 10 K/µL)

Preparation:
•Plasmaphoresis or Differential Centrifugation

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8
Q

What is the difference between using plasmaphoresis and differential centrifugation to get platelets?

A

In differential centrifugation you need donations from 5 to 6 people to equal 1 unit of platelets obtained from plasmaphoresis

**Plasmaphoresis is most commonly used

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9
Q

Suppose you have a patient with a platelet count of 49 K/µL and they are actively bleeding.
• What will you treat them with?
• compatibility?
• What will there count be after administration of 1 apheresis unit?

A
  • Platelets
  • Not ABO match necessary but platelets DO express ABO antigens
  • 74 K/µL will be the patients count after one 300 ml apheresis unit is administered

**each unit raises the platelet count by ~25 K/µL

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10
Q

How long can platelets be stored?

A

4-5 days

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11
Q

What is the most common reason to transfuse a patient?

• what will you give them?

A

Severe Anemia is the most common reason to do a blood transfusion so you’ll most likely give Packed RBCs (whole blood transfusions are rarely done)

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12
Q

What does the O-antigen consist of?

• what is it attached to?

A

Carbohydrates:
• GlcNac-Gal-GlcNac-Gal-Fructose

Attachment:
• linked to Sphingosine or membrane Protein

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13
Q

What enzyme catalyzes the transformation of the O-antigen into A or B?
• what does the enzyme do in type O people?

A

• ABO glycosyltransferase attaches a 6th sugar to the O antigen (GlcNac-Gal-GlcNac-Gal-Fructose)

Type A:
• GalNac is added

Type B:
• Gal is added

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14
Q

What is the difference between type A and B blood and type AA and BB blood?

A

Type A and B:
• these people have one allele for A or B and one allele for O

Type AA and BB:
• People have two A alleles or two B alleles

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15
Q

What type of Abs. exist against A and B antigens?

• Concentration in blood?

A

IgM antibodies so they can FIX COMPLEMENT

Conc:
• Usually present in HIGH TITER

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16
Q

What are the two most antigenic proteins on red cells?

• Number of antigenic sites on each protein?

A

RhD (one antigenic site) and it’s homolog RhCE (two antigenic sites)

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17
Q

What mothers are a risk for having antibodies that attack their fetus?
• how do we prevent this?

A

• Rh(-) mothers that have Rh(+) children may develop Rh specific antibodies during pregnancy or delivery

Prevention:
• anti-Rh-gamma

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18
Q

T or F: in an emergency situation Rh(-) individuals can be transfused with Rh(+) blood.

A

True, this is not ideal but is sometime necessary

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19
Q

If you infuse an Rh(-) individual with Rh(+) blood, what should you consider?

A

If its a female of childbearing age (or before) we do NOT want to do this because there’s and 80% chance she’ll develope Rh+ abs.

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20
Q

What immunogenic risks are there for transfusing plasma other than having to match ABO?
• most common case?

A
  • If the recipient is lacking an entire class of plasma proteins then they can make antibodies to those proteins after transfusion
  • Most Frequently happens in IgA deficiency (1/300)
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21
Q

What is the lifespan of a platelet?
• is this affected by the ABO match in the case of a transfusion?
• Limitations?

A

Platelet Lifespan:
• ~10 days

ABO types:
• Platelets express ABO antigens, because they are targeted by the immune system they will be eliminated faster but MISMATCHES ARE STILL EFFECTIVE in ACUTE situations

Limitations:
• after 5-10 transfusions platelets stop going up following the transfusion

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22
Q

What is the major exception to the fact that plasma (if you’re just giving one unit) doesn’t have to be matched?

A

1 The ABO type of the platelets need to be matched in the case that the plasma is not matched

**If recipient has very low blood volume e.g. NEONATE then you’ll want to avoid the risk by matching blood types

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23
Q

What is the difference between matching plasma and matching RBCs as far as universal donors and acceptors go?

A

RBCs:
• AB+ is a universal acceptor (O- is universal donor)

Plasma:
• O is universal acceptor (b/c they already have antibodies built up against everything, AB can’t recieve anything but AB+ because any other plasma will attach their antigens)

24
Q

T or F: anti-D (anti-Rh factor) antibodies are irrelevent in plasma transfusions

A

True, this is because people who make anti-Rh (anti-D) antibodies are not allowed to donate plasma

25
Q

When do you have to start worrying about minor (non-ABO or Rh) blood antigens coming into play?

A

In pts. that receive multiple transfusions

Blood bank has to check EVERY TIME to make sure your serum doesn’t react with these

**note: there are like 350 of these RhCE is one of them

26
Q

What is the difference between a type and screen and a crossmatch?

A

Type and Screen:
When - order if transfusion is needed or it may be needed
• Current blood specimen is typed (ABO and Rh) and screened for Abs to minor RBC antigens

Crossmatch:
When - order if transfusion is needed or prior to surgeries where major blood loss is likely
• Mix donor red cells with patient plasma and look for Agglutination (Incompatibility) under microscope

27
Q

Why is the type and screen usually not proceeded by a crossmatch?

A

99.9% of the time if the type and screen are negative the crossmatch is too

28
Q

In what cases is it okay to infuse blood into a patient that hasn’t been typed and screened?

A

O- blood can be released from the bloodbank in emergency situations

29
Q

T or F: minor blood group antigens typically become an issue immediately on transfusion.

A

False, these will only become an issue if you are transfused with blood containing that same minor blood group antigen a second time

30
Q

ANYTIME YOU SUSPECT YOUR PATIENT MAY UNDERGO SUBSTANTIAL BLOOD LOSS SEND A SAMPLE TO THE BANK

A

ANYTIME YOU SUSPECT YOUR PATIENT MAY UNDERGO SUBSTANTIAL BLOOD LOSS SEND A SAMPLE TO THE BANK

31
Q

***What is the ultimate objective of doing a RBC transfusion in the 1st place?

A

INCREASE THE PATIENTS OXYGEN CARRYING CAPACITY

32
Q

You have a severely wounded patient that has lost a lot of blood. What type of blood transfusion should you give them?
• how will hct and hgb be affected?

A

**In people who have lost a large amount of blood volume you need to replace EVERY COMPONENT OF THE BLOOD - Red cells, Platelets, Plasma

**Hct and Hgb won’t be affected

33
Q

T or F: Hbg below 7 g/dL is an indication for transfusion

A

False, most of the time lab numbers should NOT be used as an indication for transfusion

34
Q

What are the 4 REAL indications for a blood transfusion?

A

Patient is symptomatic
• INC. HR, RR, confusion/weakness/dizziness

Acute Blood Loss and/or Rapid Volume expansion

During or Immediately after acute MI
• Increased Mortality at Hgb less than 10

A clear trendline (of blood loss) that you can’t reverse

35
Q

Do pts. with renal failure need transfusions for their low RBC counts?

A

Often no because they are adapted to low Hgb

36
Q

T or F: otherwise healthy pts. can tolerate HgB less than 7 g/dL

A

True

37
Q 
RBC transfusion are NOT indicated for: 
• Old and Frail Pts. following surgery 
• Asymptomatic Coronary Artery Disease 
• Expanding Blood volume
• Promote wound healing
A 
RBC transfusion are NOT indicated for: 
• Old and Frail Pts. following surgery 
• Asymptomatic Coronary Artery Disease 
• Expanding Blood volume
• Promote wound healing
38
Q

In hypotensive patients how should you increase blood volume?

A

Isotonic IV fluids, these people don’t need more blood

39
Q

What are some conditions in which you might use plasma to replace missing plasma protein?
• For which of these is plasma the 1st choice of therapy?

A

Single Plasma Prot. Def.:
• Hemophilia A or B (Factor VIII or IX)
• Antithrombin III Deficiency
• AdamTS13 (TTP)

Mutliple Plasma Prot. Def.:
• Coumadin Toxicity with bleeding

In TTP (thombotic thrombocytopenia purpura) plasma is the 1st choice of therapy

40
Q

In what cases are platelet transfusions indicated?

A
  • Treatment of ONGOING HEMORRHAGE in thrombocytopenic pt. (plts. less than 50K/µL)
  • Prevent spontaneous hemorrhage in pts. with SEVERE THROMBOCYTOPENIA (plts. less than 10K/µL)
  • Treat or Prevent hemorrhage in pts. with DYSFUNCTINOAL PLATELETS
  • Prevent Hemorrhage in ps. undergoing INVASIVE PROCEDURES
41
Q

What is the standard of care for giving platelets to a pts. that are thrombocytopenic and undergoing an active bleed?
• Level of evidence?

A

• Transfuse the pt. with platelets at counts less than 50 K/µL

Level of Evidence:
• Weak

42
Q

What is the standard of care for platelet transfusions in severely thrombocytopenic pts?
• Level of evidence?

A

• Transfuse the pt. with platelets at counts less than 10 K/µL

Level of Evidence:
• Actually is some support that this helps

43
Q

What kind of pts. often have dysfunctional platelets that need platelet transfusion?
• Level of evidence?

A
  • Recent Cardiopulmonary Bypass
  • Treatment with irreversible platelet inhibiting drugs

Level of Evidence:
• Low

44
Q

What platelet threshold can be used for patients that need to get a central line placed?

A

20 K/µL and below it is beneficial to transfuse

45
Q

What are the 4 major categories of bad transfusion outcomes?

A
  • Immune Responses
  • Volume Overload
  • Transfusion Transmitted Infection
  • Graft vs. Host Disease
46
Q

What types of immune responses are seen in bad transfusions?
• Which is the most important?

A
  • Acute Hemolytic Reaction
  • Production of Antibody to Minor Red Cell Antigens
  • Urticarial Rxn to Transfused Plasma Proteins
  • Febrile Reaction to transfused Leukocytes
47
Q

What are some symptoms that indicate that an Acute Hemolyic Immune Response is happening post transfusion?
• What makes this type of reaction so deadly?

A

Symptoms:
• Fever, Chills, Nausea
• Chest pain, Dyspnea, Flushing
• Hemoglobinuria

Why is it deadly:
• Hgb that is free in the plasma will clog up the glomerulus in the kidney leading to renal failure

48
Q

If a patient comes back a week later and needs a second transfusion what should you do?

A

Send Blood Specimen to the blood bank to detect antibody that has been formed against MINOR Blood Group antigens

49
Q

What large group of patients are at an elevated risk of forming antibodies to minor blood group antigens?
• Why?

A

Pts. with Sickle Cell Anemia at 30% risk, while general population is at 4% risk

Why?
• Sickle Cell Pts. are typically African Americans and most blood donors are white so there is a greater likelihood that minor blood group antigens are different between donor and pt.

50
Q

What should you do if you need to transfuse a sickle cell patient?

A

Do an EXTENDED PHENOTYPE or EXTENDED CROSSMATCH

• This means that in addition to doing ABO and Rh matches, you also test for a small group of MINOR blood group antigens

51
Q

Why would you get a urticarial response after giving someone an RBC transfusion?

A

Some Plasma Proteins still remain in Packed RBCs and these are very diverse. If your body doesn’t recognize the protein then a you may get an IgE response.

***Can also cause anaphylactic reaction - MOST COMMON IN PPL. WITH IgA deficiency

52
Q

What two things should be in your DDx of immune response causing fever after Transfusion?
• How you know the difference?

A
  • Acute Hemolytic Reaction
  • Febrile Reaction due to transfused Leukocytes (1% of transfused pts)

GO EXAMINE THE PT.
• Look for Shortness of Breath, Acute Abdominal or Chest Pain, Hematuria

53
Q

What efforts are made to ensure that Febrile Reactions don’t occur due to transfused Leukocytes?
• Treatment if the Rxn does occur

A

Leukocyte Reduced Packed RBCs can be used

*Treat with Tylenol

54
Q

***What is the MOST common cause of Adverse Transfusion Reactions?
• Pts. that are particularly Susceptible?

A

VOLUME OVERLOAD***

Pts. Susceptible:
• CONGESTIVE HEART FAILURE pts. are less likely to handle the increased work load

55
Q

How much is blood volume increased with 2 units of packed RBCs?
• What adverse effects does this have in pts. with congestive heart failure?
• What do you do if you are afraid a pt. is suffering from volume overload?

A

10%

Adverse Effects in CHF:
• Failure to handle extra cardiac workload lead to edema and fluid accumulation in organs INCLUDING the LUNGS

Treatment of Vol. Overload:
• Diuretics are used to reduce the blood volume

56
Q

What is the current risk for transmitting HIV, HCV, HBV or other viruses to people via a blood transfusion?
• How do we prevent this?

A

1 in 100,000

Prevention:
• Screen Donors
• Use PCR based tests to screen serum

57
Q

What cause GVHD in transfused pts.?
• What pts. are at the greatest risk?
• How do we reduce risk?

A

GVHD
• Mediated by Leukocytes against host tissues (G.I. Epithelial Sloughing)

Who:
• Occurs most commonly in Immunocompromised Recipients

Risk Reduction:
• Leukocyte Reduced RBCs
• Irradiation of Blood Kills Leukocytes (0% risk of GVHD)

Heme - Strom (13 decks)

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