Download Whole Blood Peripheral Blood Smear (CBC)

Blood Transfusions:
Everything You’ve Always Wanted to
Know, But Didn’t Know Who to Ask
Anne Eder, MD PhD
Executive Medical Officer
American Red Cross
National Headquarters, Biomedical Services
Washington, D.C.
[email protected]
Whole Blood
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Composed of:
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Liquid
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Cellular
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Plasma
Platelets
White Cells
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Neutrophils
Lymphocytes
Monocytes
Red cells
Buffy coat
Hematocrit
38-45%
Peripheral Blood Smear (CBC)
Red Cells
Hemoglobin
Men:
16 + 2 g/dL
Women: 14 + 2 g/dL
White Cells
4,500 – 11,000 WBC/μL
Platelets
150-400,000 platelets/μL
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Red Cells (Erythrocytes)
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Carry oxygen to tissues
Remove carbon dioxide
from tissues
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Red Cells (“Packed RBC”)
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~14 million units/year in U.S.
Usually stored for 5-6 weeks
at 4-10oC
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Red Cells (Erythrocytes)
Transfusions are used to treat:
„ Active bleeding (hemorrhage)
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Surgery
Trauma
Anemia
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Decreased RBC production
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Increased RBC destruction
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e.g. chemotherapy, bone marrow failure
e.g. sickle cell anemia
Expected response to transfusion:
„ 1 RBC unit increases hemoglobin by 1.0 g/dL
White Cells (leukocytes)
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Fight infections
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WBCs in RBC or platelets can cause transfusion reactions
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Febrile
F
b il nonhemolytic
h
l ti reactions
ti
Cytomegalovirus infection
Alloimmunization
Component preparation
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Engulf (phagocytize) bacteria to destroy them
Generate antibodies
Leukoreduction removes 99.9% WBC
Irradiation inactivates WBC (lymphocytes); prevents TA-GVHD
Rarely, WBC (neutrophil) transfusions to treat lifethreatening infections that don’t respond to standard
treatment if marrow recovery is expected
Typically 1 WBC per 1000 RBC
2
Platelets (thrombocytes)
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Important in clotting (stop bleeding)
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Secrete serotonin, which constricts blood vessels to slow
bleeding
Activate plasma proteins that form fibers,
fibers which serve as a net to
stop leaking red cells.
Smaller than RBCs on a peripheral blood smear
Can only be stored for 5 days with continuous
gentle agitation at 20-24oC
Typically 25 platelets per 1000 RBC
Clotting Schematic
Odyssey Magazine, 2010
Platelets
Fibrin
Endothelia
Collagen
Platelet Count and Bleeding
Normal: 150-400,000/μl
Gaydos et al NEJM 1962
Slichter and Harker1978
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Petechial Hemorrhage
Platelet therapy
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Single donor platelets (SDP)
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Whole Blood Platelets
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Apheresis yields 1-3 doses
“Random
“R
d
d
donor platelets”
l t l t ” (RDP)
4-6 products pooled for 1 dose
Prophylactic use for low platelet
count (thrombocytopenia)
Therapeutic use to stop bleeding
Expected response to transfusion (adults):
• 1 RDP unit increases platelet count by
• 6 RDP units (1 pool) or 1 SDP by
5,000-10,000 /µL
30,000 -60,000/µL
Plasma
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Yellowish fluid, approx. 55% of
whole blood donation
Contains antibodies, clotting factors
Used to treat bleeding patients with
multiple clotting factor deficiency
Source for further fractionation
(separation) for factor concentrates
(e.g., Factor VIII)
Normal Plasma
Expected response to transfusion (adults):
• 1 plasma unit (~250 mL) - 1 unit/mL clotting factors; 400 mg
fibrinogen; clinical response monitored by PT, PTT or bleeding
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Blood Banking
„
The process of
collecting,
manufacturing, testing,
storing and distributing
blood products for
patient care
Apheresis Donation (e.g., platelets)
Every Donation is Tested
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ABO, Rh (blood type), Ab screen
Hepatitis B
HBsAg, Anti-HBc, Nucleic Acid Test
Hepatitis C
Antibodies, Nucleic Acid Test
HIV 1/2
A tib di
Antibodies,
N
Nucleic
l i A
Acid
id T
Testt
HTLV I and HTLV-II
Antibodies
Syphilis
Antibodies
West Nile Virus
Nucleic Acid Test
T. cruzi (Chagas)
Antibodies
Bacteria
Platelets only
Optional
CMV (Cytomegalovirus) Antibodies
Sickle cell trait
Screen for hemoglobin S
5
Transfusion-transmitted Infections
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Risk of a potentially infectious unit is calculated
from mathematical models:
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Hepatitis B
Hepatitis C
HIV
1: 282
282,000
000
1: 1,149,000
1: 1,467,000
Lookback and investigations of suspected
infections suggest risk is even lower (4 cases of
transfusion-transmitted HIV have been documented
since NAT introduced in 2004)
Red Cell Compatibility:
Blood type
(RBCs)
O
A
B
AB
A
A
Plasma
antibodies
Frequency (%)
Compatible RBC
transfusion
Anti-A, anti-B
A ti B
Anti-B
Anti-A
None
A
45%
41%
10%
4%
O
A or O
B or O
All (A, B, O or AB)
A anti-B
anti-B B
B
Group A
..if INCOMPATIBLE….Agglutination and Hemolysis
Noninfectious Complications
Febrile
Allergic
Anaphylaxis
1:100
1:100
1:20,000 to 50,000
V l
Volume
overload
l d
1 100 tto 1
1:100
1:200
200
Septic (bacteria)
1:5,000,000 (red cells)
1:250,000 (apheresis platelets)
TRALI
1:440,000 (red cells)
1:250,000 (plasma, male predominant)
Hemolytic – acute
(ABO incompatible)
1:12,000 to 1:38,000
Hemolytic - delayed
1:5400 to 1:62,000
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Every transfusion should be monitored…..
Symptoms
Differential Diagnosis
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Acute hemolytic reaction (ABO incompatible)
Febrile nonhemolytic reaction
Sepsis (bacterial contamination of unit)
Hives, itching
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Allergic transfusion reaction
Difficulty breathing
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Fever
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Lower back pain
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Allergic transfusion reaction
Transfusion-associate circulatory overload
Transfusion-related acute lung injury
Acute hemolysis (ABO incompatible)
Delayed hemolysis
Questions?
Anne Eder, MD PhD
Executive Medical Officer
American Red Cross
National Headquarters, Biomedical Services
Washington, D.C.
EderA @ usa.redcross.org
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