Blood products and transfusion Flashcards
What are the two main components of blood?
Cellular elements (RBCs, WBCs, platelets) and plasma.
What happens when blood is centrifuged?
Plasma rises to the top, solutes settle to the bottom, platelets in the middle.
What is the effect of high cholesterol on centrifuged blood?
Fat gel layer may form on top.
What are the blood types and Rh factor percentages?
Types: A, B, AB, O; Rh+ ~85%, Rh- ~15%.
Why is Rh status important in transfusion?
Rh incompatibility can lead to fetal issues in pregnancy and immune responses.
What is the universal donor and recipient?
Universal donor: O negative; Universal recipient: AB positive.
Why are females of childbearing age typically given O negative blood?
To prevent Rh sensitization and future fetal hemolytic disease.
What is the purpose of a type and screen?
Identifies ABO/Rh and screens for antibodies/antigens.
Why can type and screen take time?
Screening for hundreds of possible antibodies can delay processing.
Why is type and screen important for high-risk surgeries?
Prepares for potential transfusion and avoids emergency uncrossmatched transfusions.
What transfusion fluid was used in WWI/Vietnam?
Whole blood.
What replaced whole blood in the 1970s-1990s?
Component therapy (RBCs, FFP, etc.).
Why was normal saline originally used?
Rehydration for cholera, not designed for resuscitation.
What are the problems with crystalloid resuscitation?
Dilutes blood, causes inflammatory response, and disrupts microclots.
What are the four main blood components?
PRBCs, FFP, Cryoprecipitate, Platelets.
What is LTOWB?
Low Titer O Whole Blood – screened for minimal antibodies.
What does CPDA-1 do in blood storage?
Citrate chelates calcium, phosphate buffers, dextrose is fuel, adenine extends ATP production.
What happens to 2,3-DPG in stored blood?
Decreases over time, shifting O2 curve left and impairing oxygen delivery.
How are PRBCs prepared?
By removing 200-250mL plasma from whole blood.
What is the volume of PRBCs?
Typically 200-350mL.
What is the effect of PRBC transfusion?
Increases Hb by ~1g/dL and Hct by 3%.
Do PRBCs contain platelets or granulocytes?
No.
How is FFP prepared?
Plasma removed from WB within 8 hours, frozen at -18°C.
What is in FFP?
Water, carbs, fats, minerals, clotting proteins (stable and labile).
How much FFP is needed to raise clotting levels?
10–15 mL/kg raises factors by ~2-3%.
What is cryoprecipitate?
Protein-rich fraction from thawed FFP containing Factor VIII, vWF, fibrinogen, Factor XIII.
When is cryo used?
Massive transfusion, congenital bleeding disorders, fibrinogen replacement.
How are platelets prepared?
From PRP or apheresis, then re-centrifuged.
What is the volume of apheresis platelets?
250-300mL.
How much does one unit of platelets increase PLT count?
5,000-10,000.
How do pooled platelet units affect PLT count?
6-pack or 10-pack increases PLT by 60,000–100,000.
Why should platelets not be warmed?
Causes aggregation; academic importance.
What fluids are safe with blood transfusion?
Normal saline, Normosol, or PlasmaLyte.
Why avoid Lactated Ringers with blood?
Contains calcium which can cause clotting.
Why must blood be warmed?
To prevent hypothermia and coagulation impairment.
What devices are used to warm blood?
Belmont, Level 1, Ranger, others.
Why is whole blood advantageous?
Fewer additives, superior coagulation, easier logistics.
How does whole blood compare to component therapy?
Less diluted, better platelet & factor levels, single product.
What causes hypocalcemia during transfusion?
Citrate binds ionized calcium (iCa).
What are signs of transfusion-induced hypocalcemia?
QT prolongation, seizures, ↓ cardiac output.
When should calcium be replaced?
Every 4 units of blood; monitor iCa.
Which calcium replacements are used?
Calcium chloride or gluconate.
What are signs of hemolytic transfusion reactions?
Fever, chills, hypotension, dyspnea, hemoglobinuria.
What mediates acute hemolytic reactions?
IgM antibodies and complement.
What are symptoms of allergic transfusion reactions?
Itching, urticaria, erythema, anaphylaxis.
What is TRALI?
Acute lung injury within 6 hours of transfusion, non-cardiogenic.
What are TRALI signs?
Hypoxemia, bilateral infiltrates, no JVD, minimal diuretic response.
What is TACO?
Volume overload causing pulmonary edema.
How do TACO and TRALI differ?
TACO has HTN, JVD, responds to diuretics; TRALI does not.
What causes delayed hemolytic reactions?
IgG antibodies.
What is transfusion-associated GVHD?
Viable donor lymphocytes attack host; causes pancytopenia.
How is GVHD prevented?
Irradiated cellular products.
What is post-transfusion purpura?
Antibodies against platelets cause thrombocytopenia.
What are signs of bacterial contamination in blood?
Fever, shock, hemoglobinuria.
What causes it?
Gram-negative endotoxins; improper handling.
What is transfusion-induced hemosiderosis?
Iron overload from repeated transfusions.
How is hemosiderosis managed?
Chelation therapy or reduced transfusion frequency.
What qualifies as an adult massive transfusion?
Replace total blood volume in 24h, 50% in 3h, or 4 units in 4h.
What is the standard MTP ratio?
1:1:1 PRBCs : FFP : Platelets.
Why is whole blood better in MTPs?
Higher hemostatic potential, fewer additives.
What are key TEG parameters?
R-time, K-time, MA, Ly30.
What does a prolonged R-time indicate?
Coagulation factor deficiency; give FFP.
What does low MA mean?
Platelet dysfunction; give platelets.
What does rapid clot lysis (Ly30) suggest?
Hyperfibrinolysis; give cryoprecipitate.
What are initial steps after suspected transfusion reaction?
Stop transfusion, keep IV open, notify blood bank, send blood/urine samples.
Why should you be cautious declaring a transfusion reaction?
It may delay further transfusions crucial for patient survival.
