Transfusion

Question 1

Apherisis vs. whole blood donation:

Answer 1

Whole blood donation takes about 10 minutes

Apheresis is the process of removing a specific component (e.g. platelets) which usually takes 45 minutes and can cause hypocalcemia because returned blood is citrated.

Question 2

Forward typing:

Answer 2

Tests the patient’s red cells with anti-A and anti-B reagents (tests for the presence of antigens on the surface of red cells)

Question 3

Reverse typing:

Answer 3

Tests for the presence of antibodies in the patient’s serum or plasma. Tests using the patient’s serum or plasma with commercial group A and group B red cells.

Question 4

How would someone have preformed antibodies to a blood antigen?

Answer 4

Pregnancy

Transfusion

Solid organ transplant

Question 5

How is the indirect Coomb’s test used in blood typing/screening?

Answer 5

Coomb’s reagent is an IgM antibody against human IgG

Question 6

What are possible transfusion complications?

Answer 6

-Transfusion reactions

• Transfusion-associated circulatory overload (TACO)
• Acute / delayed hemolytic
• Febrile nonhemolytic
• Transfusion-related acute lung injury (TRALI)
• Allergic
• Anaphylactic
• Infection
• New antibody formation secondary to exposure

Question 7

Acute Hemolytic Transfusion Reaction:

Answer 7

Destruction of transfused red cells during, immediately after, or within 24 hours following transfusion of red cells

Risk: 1 in 76,000 transfusions (fatal: 1 in 1.8 million)

Symptoms: Fever, chills, hypotension, DIC/oozing, hemoglobinuria, back pain

Stopping the transfusion is always the first step in any suspected transfusion reaction

Order a transfusion reaction workup

Send remaining blood to blood bank, and pre/post-transfusion urine and plasma samples

Question 8

What is involved in a transfustion reaction workup?

Answer 8

First priority is to evaluate for hemolysis

Clerical check

Serum color check

Free urine hemoglobin

Retype patient

Direct Antiglobulin Test (IgM added to pt RBCs)

Determines if antibody is coating patient’s RBCs after transfusion

Question 9

Acute hemolysis:

Answer 9

Severity correlates with amount of blood transfused

• Stresses importance of starting infusion slowly

Most serious due to transfusion of ABO incompatible PRBCs (group A unit to O recipient)

• Anti-A usually higher titer than anti-B

Activation of complement and coagulation system causes disseminated intravascular coagulation (DIC), hypotension and renal failure

Question 10

Treatment of AHTR:

Answer 10

Continue IV fluids (0.9% NaCl)

Maintain blood pressure with vasopressor (dopamine 400mg in 250mL D5)

Maintain renal output > 100mL/hr

Fluid replacement +/- diuretic (furosemide 1mg/kg body weight or 20-80mg IV)

Maintain airway

Fibrinogen, D-Dimer, PT, PTT to watch for DIC

BUN, Creatinine to watch for renal failure

Question 11

Delayed hemolytic transfusion rections:

Answer 11

Reagent red cells obtained from group O donors

Symptoms appear 24 hours to 28 days post-transfusion

Less severe, usually require no treatment

IgG from red cell exposure from prior transfusion or pregnancy

Inadequate increase of post-transfusion Hgb levels, rapid decrease, spherocytes

Typically low-titer antigens below cutoff sensitivity on initial Ab screen

• Kidd, Duffy, Kell, MNS

Question 12

TRALI:

Answer 12

Transfusion Related Acute Lung Injury

HLA or HNA in the donor

Risk: 1 in 1200 to 1 in 1900

Can be potentially life-threatening or fatal

Overlaps with circulatory overload and anaphylactic reactions

Definition: Noncardiac pulmonary edema that follows transfusion of plasma-containing products

Question 13

TRALI criteria:

Answer 13

1.Acute onset during or within 6 hours of transfusion

2. Hypoxemia (PaO2:FiO2 < 300 or O2 sat < 90% on room air)
3. Bilateral pulmonary infiltrates on CXR
4. Hypotension
5. No preexisting acute lung injury, no competing risk factors for acute lung injury & no evidence of circulatory overload (elevated pulmonary arterial wedge pressure)

Question 14

TRALI treatment:

Answer 14

Respiratory and/or pressor support

Most recover clinically within 72 hours

Infiltrates resolve within 2-4 days

Defer donor from donating future plasma-containing products

Question 15

TACO:

Answer 15

Transfusion Associated Circulatory Overload

Patient’s cardiopulmonary system exceeds its volume capacity

Dyspnea, headache, peripheral edema, hypertension

Compromised cardiac and pulmonary status

Administer O2 and diuretics

To prevent, transfuse at a slow rate in small-volume aliquots over 4 to 6 hours

Large plasma infusions should be avoided

Question 16

TRALI vs. TACO - how can you tell?

Answer 16

TRALI will present with HYPOtension

TACO will present with HYPERtension

Question 17

Febrile Nonhemolytic Transfusion Reactions:

Answer 17

Caused by recipient HLA antibodies to HLA antigens on the donor lymphocytes. Cytokines released by WBCs during blood product storage.

Prevent by reducing the leukocytes in the blood products prior to storage.

Question 18

Allergic/Anaphylactic Transfusion Reactions:

Answer 18

Risk:

• 1-3% allergic
• 1 in 20,000 to 50,000 anaphylactic

Two or more, observed within 4 hours of transfusion are definitive for allergic transfusion reaction:

• Urticaria
• Pruritis
• Maculopapular rash
• Flushing, edema
• Erythema (periorbital)
• Respiratory distress
• Hypotension

Question 19

Treatment of Allergic Reactions:

Answer 19

Stop the transfusion

Administer antihistamines

• Diphenhydramine 25-50 mg depending on severity
• If patient prone to allergic reactions, premedicate with 25-50 mg Diphenhydramine 30 mins prior to transfusion

Once symptoms have abated, it is safe to continue transfusion

Question 20

Bacterial Contamination of Platelets:

Answer 20

From skin flora at time of collection

Suspect when high fever, chills, hypotension

May be after the end of transfusion

Ask BB to take sterile aliquot from bag to Micro lab

Order blood cultures