Transfusion Medicine Flashcards
Concept of blood component therapy
Centrifuge bag of donated whole blood and separate into parts…each component cn go to a different patient
Whole blood
Contains everything that came from the donor
RBCs, WBCs, platelets, proteins (including coag factors)
Total bag volume and temp
slightly greater than 500 mL
4C fridge
Indication for transfusion of whole blood
Only one is to treat patients who are experiencing massive bloodloss
This is rarely done
Benefits of whole blood transfusion
RBC replaces patients lost RBCs so increases O2 capactiy
Plasma portion replaces lost intravascular blood volume and prevents CV collapse
Limitations of Whole Blood
Not a good source for platelets due to fridge
Not a good source for coagulation factors (especially 5 and 8) due to fridge
Capable of transmitting infectious dzs
RBC volume and storage
Same number of RBCs as wholeblood
225 to 350 mL
4 C fridge
Indication to transfuse RB
Increase RBC mass…and increase O2 carrying capacity in the anemic patient
Decision to transfuse anemic patient with packed cells depends on
HgB and Hct of patient - if HgB less than 7 or HcT less than 21% (general)
Clinical situation - more important…symptomatic may need transfusion regardless of count…if not symptomatic, may want to withold, even if counts are low
Hematologic response to packed cells
Transfusion of one unit should increase HgB by 1 and HcT by 3%
Limitations of packed cells
Not a good source for platelets or coagulation factors
Capable of transmitting infection
LRBC
Leukocyte reduced RBCs….99.9% of leukocytes removed by passing blood through special filter
Indication for transfusion and how it is commonly used
Same as RBCs (packed cells)
Commonly used in patients prone to febrile non-hemolytic transfusion reactions (FNHTRs)…occur in patients with ABs against foreign antigens present on membranes of leukocytes that are present within donated blood…produces fever and chills
LRBC is BEST blood component to prevent FNHTRs
LRBC limitations and advantage
Besides preventing FNHTRs, prevents CMV transmission
Limitations same as packed cells
WRBCs
Washed RBCs…removal of all plasma
Indication for transfusion of WRBCs and how commonly used
Same as packed cells
Best to use in anemic patient with history of allergic transfusion reactions (ATR) to human plasma proteins…clinical manifestations are anaphylaxis to hives
LImitations of WRBCs
Not a good source for platelets or coag factors
Capable of transmitting dz
PC aka RDP including storage and volume
Platelet concentrate (random donor platelet) Derived form oneunit of WB and is platelets in 50 mL plasma...stored at room temp
Indications for RDP trnasfusion
Thrombocytopenic or has throbocytopathy (aspiriin use could cause)
Guidelines for transfusing thrombocytopenic patients
If bleeding or about to go to surgery AND platelet<50,000 consider PC transfusion
If not bleeding AND platelet count less than 10,000, consider PC transfusion…prophylactic transfusion will prevent hemorrhage in brain
DOse and response to RDP
1PC/10kg body weight
1 PC shoud increase platelets by 5,000 to 10,000
Disadvantage of RDP
Infectious dz
Apheresis platelet
Number of platelets equivalent to 6 units of PC
FFP with storage
Fresh frozen plasma
Plasma of 1 unit of WB separated and frozen within 8 hours…then thawed in 37 degree water bath when need
FFP advantage
Quick freeze preserves ALL coag factors…even 5 and 8
Indication for FFP transfusion
Tx of bleeding patients who have multiple coag factor deficiencies (cirrhosis, DIC)…offers coag factor replacement
Effectiveness of FFP therapy
Evaluated by comparison of pre and post PT and PTT
Disdvantage of FFP
Infectious dz
Cryo aka AHF
Cryoprecipitate aka cryoprecipitated antihemophilic factor
AHF formed when
FFP thawed at 4C…precipitate removed and then frozen…thawed and pooled before use
AHF rich in
Clotting factors - Fibronogen (factor 1), von Willebrand (vWF), factor 8, and factor 13
Indication for AHF transfusion
Bleeding patient deficient in one of factors it includes Von Willebrands dz (vWF) Hemophilia A (Factor 8 def) Factor 13 def (rare) Fibrinogen def
Cryo is most appropriate
Blood componenet to be used for these dz
Cryo disadvantage
Infectous dz
Blood derivatives
Drugs derived from human plasma
Albumin, Immune globulin, Rh immune globulin, Factor 8 concentrate
Hemolytic transfusion txns
RBC membranes contain carbs and proteins which functon as antigens in transfusion setting
Acute hemolytic transfusion reactions
AHTR
Within 4 hours of transfusion
uncommon
Mech of AHTRs
IgM ABs in recipients bloodstream activate complement…donor RBCs hemolyse intravascularly
Most common cause of AHTR and almost always due to
Human error
IgM Abs directed against donor ABO red cell antigens
Signs of AHTRs and tx
Fever, pain at IV site, hemoglobinemia and uria, renal failure due to excess plasma hemoglbin in renal tubules, hypotnesion/schock/DIC due to released RBC stroma, hyperkalemia due to release of K from hemolyses donor RBCs, death
STOP transfusion and seek supportive care
DHTR
Fairly common
5-21 days after
DHTR mech
IgG antibodies get phagocytosed by liver and spleen (extravascular hemolysis)…positive Coombs test helps diagnose
Why do DHTRs occur
Offending AB is too low to detect in recipient
ABs of DHTRs directed against
Non-ABO antigens
Maybe Rh antigen
Symptoms and signs of DHTR and tx
Mild, possibly asymptomatic
Fever
Jaundice
Possibly none, monitor Hb and Hct
How to prevent DHTR in future
Blood bank staff can ID antibody in patient’s post trnasfusion blood specimen courtesy of response
Infectious agents to be concerned of
HIV 1/2 HTLV 1/2 HBV (highest risk) HCV West nile virus (lowest risk)
