1

Blood Transfusions:

Everything You’ve Always Wanted to Know, But Didn’t Know Who to Ask

Anne Eder, MD PhD

Executive Medical OfficerAmerican Red Cross

National Headquarters, Biomedical ServicesWashington, D.C.

edera@usa.redcross.org

Whole Blood Composed of:

Liquid Plasma

CellularPlateletsWhite Cells

NeutrophilsLymphocytesMonocytes

Red cells

Buffy coat

Hematocrit38-45%

Peripheral Blood Smear (CBC)Red Cells

Hemoglobin Men: 16 + 2 g/dLWomen: 14 + 2 g/dL

White Cells

Platelets

Women: 14 + 2 g/dL

4,500 – 11,000 WBC/μL

150-400,000 platelets/μL

2

Red Cells (Erythrocytes)Carry oxygen to tissuesRemove carbon dioxide from tissues

Red Cells (“Packed RBC”)~14 million units/year in U.S.Usually stored for 5-6 weeks at 4-10oC

Red Cells (Erythrocytes)Transfusions are used to treat:

Active bleeding (hemorrhage)SurgeryTraumaTrauma

Anemia Decreased RBC production

e.g. chemotherapy, bone marrow failureIncreased RBC destruction

e.g. sickle cell anemia

Expected response to transfusion:1 RBC unit increases hemoglobin by 1.0 g/dL

White Cells (leukocytes)Fight infections

Engulf (phagocytize) bacteria to destroy themGenerate antibodies

WBCs in RBC or platelets can cause transfusion reactions F b il h l ti tiFebrile nonhemolytic reactions Cytomegalovirus infectionAlloimmunization

Component preparation Leukoreduction removes 99.9% WBC Irradiation inactivates WBC (lymphocytes); prevents TA-GVHD

Rarely, WBC (neutrophil) transfusions to treat life-threatening infections that don’t respond to standard treatment if marrow recovery is expectedTypically 1 WBC per 1000 RBC

3

Platelets (thrombocytes)Important in clotting (stop bleeding)

Secrete serotonin, which constricts blood vessels to slow bleedingActivate plasma proteins that form fibers which serve as a net toActivate plasma proteins that form fibers, which serve as a net to stop leaking red cells.

Smaller than RBCs on a peripheral blood smearCan only be stored for 5 days with continuous gentle agitation at 20-24oC Typically 25 platelets per 1000 RBC

Clotting Schematic

PlateletsPlatelets

Fibrin

EndotheliaCollagen

Ody

ssey

Mag

azin

e, 2

010

Normal: 150-400,000/μl

Platelet Count and Bleeding

Gaydos et al NEJM 1962 Slichter and Harker1978

4

Petechial Hemorrhage

Platelet therapySingle donor platelets (SDP)

Apheresis yields 1-3 doses

Whole Blood Platelets“R d d l t l t ” (RDP)“Random donor platelets” (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 5,000-10,000 /µL • 6 RDP units (1 pool) or 1 SDP by 30,000 -60,000/µL

PlasmaYellowish fluid, approx. 55% of whole blood donation Contains antibodies, clotting factors

Normal Plasma

Used to treat bleeding patients with multiple clotting factor deficiencySource for further fractionation (separation) for factor concentrates (e.g., Factor VIII)

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

5

Blood BankingThe process of collecting, manufacturing, testing, storing and distributing blood products for patient care

Apheresis Donation (e.g., platelets)

ABO, Rh (blood type), Ab screenHepatitis B HBsAg, Anti-HBc, Nucleic Acid Test Hepatitis C Antibodies, Nucleic Acid TestHIV 1/2 A tib di N l i A id T t

Every Donation is Tested

HIV 1/2 Antibodies, Nucleic Acid TestHTLV I and HTLV-II AntibodiesSyphilis AntibodiesWest Nile Virus Nucleic Acid TestT. cruzi (Chagas) AntibodiesBacteria Platelets onlyOptional CMV (Cytomegalovirus) Antibodies

Sickle cell trait Screen for hemoglobin S

6

Transfusion-transmitted Infections

Risk of a potentially infectious unit is calculated from mathematical models:

Hepatitis B 1: 282 000Hepatitis B 1: 282,000Hepatitis C 1: 1,149,000HIV 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)Plasma

antibodiesFrequency (%) Compatible RBC

transfusion

O Anti-A, anti-B 45% OA A ti B 41% A OA Anti-B 41% A or OB Anti-A 10% B or O

AB None 4% All (A, B, O or AB)

..if INCOMPATIBLE….Agglutination and Hemolysis

A anti-BAA

ABanti-B

BGroup A

Febrile 1:100Allergic 1:100

Anaphylaxis 1:20,000 to 50,000V l l d 1 100 t 1 200

Noninfectious Complications

Volume overload 1:100 to 1:200Septic (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

7

Symptoms Differential DiagnosisFever Acute hemolytic reaction (ABO incompatible)

Febrile nonhemolytic reaction Sepsis (bacterial contamination of unit)

Every transfusion should be monitored…..

Hives, itching Allergic transfusion reactionDifficulty breathing Allergic transfusion reaction

Transfusion-associate circulatory overloadTransfusion-related acute lung injury

Lower back pain Acute hemolysis (ABO incompatible) Delayed hemolysis

Questions?

Anne Eder, MD PhD

Executive Medical OfficerAmerican Red Cross

National Headquarters, Biomedical ServicesWashington, D.C.

EderA @ usa.redcross.org