transfusion Flashcards
what are the available blood products
packed rbc, plasma, cryoprecipitate, platelets
what do you use to increase oxygen carrying capacity
packed rbc
what do you use to replace clotting factors
plasma
what do you use to stop bleeding when a patient has a low platelet count, or rarely - to prevent bleeding with low platelet count
platelets
what is the term for low platelet count
thrombocytopenia
what is plasma also called
FFP fresh frozen plasma
what is max storage time for packed rbc and why was it chosen
42 days bc only up to 25% of stored rbc will lyse within 24 hours of transfusion
how do you prep packed rbc
differential centrifugation- spin them down, pull of plasma and platelets
how many mL are in 1 unit of blood (packed rbc)
250 mL
how much will 1 unit of packed rbc increase hemoglobin by
1 g/dL
do packed rbc have to be abo comp
yes
what are leukoreduced prbcs
steps were taken to remove MOST leukocytes
what are irradiated prbcs
all leukocytes were killed
when do you use cryoprecipitate
to replace fibrinogen, factor VIII, factor XIII, and vWF
what is cryoprecipitate
proteins that precipitate out of plasma at 4 degrees
cryoprecipitate is used to treat genetic or acquired def of the factors but factor VIII def (hemophilia A) is usually treated with
factor VIII concentrate
what is factor VIII def
hemophilia A
what is vWF def usually treated with
“by other means” other than cryoprecipitate
why is cryoprecipitate’s low risk volume ratio better than plasma sometimes
bc it requires only low volumes and thus will not get the volume overload that plasma may cause
how do you prepare plasma
differential centrifugation, spin down red cells and pull off the plasma
how much is in 1 unit of plasma
200-250 mL
how much will 1 unit of plasma increase clotting factors by
20%
what is plasma stored at
-20 degrees
does plasma have to be abo comp
yes
how much is in one unit of cryoprecipitate
15 mL
how much does 1 unit of cryoprecipitate raise factor level by
5-10 mg/dL
what can you store cryoprecipitate at
-20 deg
does cryoprecipitate have to be abo comp
no
when do most people start spon bleeding
platelet count below 10 K per microL
when are platelet transfusions ordered
low platelet count AND bleeding
how are platelets prepared
usually plasmaphoresis but less often diff centrifugation
how does differential centrifugation work with platelet prep
get 1 unit of blood per donor (x 5 donors) = about same number of platelets per apheresis unit
do platelet preps contain donor plasma
yes
do platelets express abo antigens
yes
how is prep done for platelet plasmapheresis
Spin down the red cells in a continuous flow centrifuge
Pull off the platelets, reinfuse red cells and plasma
how many mL per apheresis unit of platelets
300
how much will 1 unit increase platelet count by
25 K/microL
what is normal platelet count
150-450 K/microL
can you refrigerate platelets
no
how long is room temp storage life for platelets
4-5 days
do platelets have to be abo comp
no
what is most common reason to transfuse patient
severely anemic (cannot transport enough oxygen to stay alive)
what do you transfuse in anemic patients
packed rbcs
what do you want to avoid in blood transfusion
having patient’s immune system attack and lyse the transfused cells
what kind of antigens are on red cells surface
number of proteins; and complex carbs on lipids or proteins
what is the core structure of the complex carbs on red cell surface
O antigen
what is the H antigen
4 sugar precursor to the O antigen seen in very rare cases - WE NEED TRANSFUSION SPECIALISTS
What is structure of O antigen
5 linked hexameric sugars
what are the 5 sugars in O antigen
GlcNac, Gal, GlcNac, Gal, Fucose
what does ABO glycosyltrasnferase do
attaches 6th sugar to O antigen
for the A allele what does ABO glycosyltrasnferase transfer to O antigen
GalNac
for the B allele what does ABO glycosyltransferase transfer to O antigen
Gal
for the O allele what happens to the ABO glycosyltransferase
inactive
what are individuals terms with two A alleles
blood group A
what are individuals termed with two ABO glycosyltransferases that transfer GalNac
blood group A
what are individuals terms with two B alleles
blood group B
what are individuals termed with two ABO glycosyltransferases that transfer Gal
blood group B
individuals with only O alleles are termed
blood group O
what are individuals termed with two ABO glycosyltransferases that are inactive termed
blood group O
what are individuals with one A and one B allele termed
blood group AB
what are individuals termed with one ABO glycosyltransferase that carries GalNac and one that carries Gal
blood group AB
what are individuals with one O allele and one A allele termed
blood group A
what are individuals with one O allele and one B allele termed
blood group B
what are individuals termed with one ABO glycosyltransferase that is inactive and one that carries GalNac
blood group A
what are individuals termed with one ABO glycosyltransferase that is inactive and one that carries Gal
blood group B
what antibodies do most type A individuals produce
antibodies to B antigen that are IgM, present in high concentration or titer
how do antibodies to blood antigens lyse rbc
fix complement
who can type O blood be tranfused to
anyone
what happens if patient is transfused
lyse them all very quickly called acute hemolytic transfusion rxn
what is antigenicity
a measure of how likely it is that a potential antibody binding site will actually induce an antibody response
are antibodies always hemolytic for protein antigens on rbc
no
what are tge two most antigenic proteins on red cells
RhD and RhCE
what is the mmost common and significant allelic variation in Rhd
a complete deletion of the coding sequence
The Rhd gene duplicated and formed what
RhCE to have C/c and E/e antigenic sites
what are individuals with two deleted D alleles called
Rh negative or D negative
15% of europeans have what type of Rh
Rh negative which means they make antibodies to Rh
pregnancy can immunize what type of mother to D
D-
what can anti-d antibodies do in pregnancy
lyse fetal red cells, causing spontaneous abortion OR severe anemia (hemolytic disease of the newborn).
how can Immunization during pregnancy and/or delivery can be prevented
anti-Rh-gamma globulin
no women at or below childbearing status must ever be able to develop what type of antibody
anti d
we need to know what status for donors and recipients of transfusions
d antigens and antibodies
over 80% of d- inviduas tranfused with d+ blood develop what and who is this acceptable for
anti d antibodies; males and OLDER females
for d- girls and young women what type of blood must never be transfused
d+
what type of blood must be transfused if they have anti d antbidoes
d-
can d+ cells be transfused to d- patients
yes
does plasma contain abo antigens
yes
if a recipients lacks an entire class of plasma proteins what can develop after transfusion and what is most common example
antibodies; people lacking IgA (if transfused after having dev antibodies, can dev a severe allergic reaction)
how long do platelets normally live
10 days
if ABO incompatible what happens to platelets in transfusion
their survival will be shortened, but that is not felt to impair their utility for treating an acute bleeding episode.
do platelet preps contain plasma
yes , about 1 unit per unit
is it ok to transfuse incomp ABO plasma in platelet transfusion
yes
if a patient has a low blood volume (neonate), risk associated with incomp abo plasma is what compared to normal and is avoided by what
higher; abo compatible transfusion or resuspending platelets in low volume plasma
Patients tend to become less responsive to platelet transfusion after how many transfusions
5-10; platelets stop going up
patients who donate plasma are not allowed to have what in their blood
anti d antibodies
After one or more transfusions, patients can develop antibodies to what
other minor red cell antigens
blood banks must screen recipients for any what prior to transfusion
antibodies to red cell antigens
what is process of getting compatible red blood cells from bank?
physician provides recipient sample to get tested for ABO type, Rhd status and screened for antibodies for any known red cell antigens; a crossmatch usually performed
what is a crossmatch
mix donor red cells and recipient plasma - look for agglutination
in an emergency you take a chance by transfusing with
O negative, type compatible units
what happens if the antibody test is positive when testing for compatibility of red blood cells
identify antibody/antibodies, obtain pRBCs that do not contain antigen, perform cross match
if your patient is going into surgery what do you need ready and why
2 units of prbcs ready in case of unexpected bleeding, if you wait until they need it the time it takes to identify compatible units can be the difference between keeping your patient alive and not doing so if antibody test is positive
what is the objective of red cell transfusion
increases patient’s oxygen carrying capacity
what is the stuff in blood that carries oxygen
hemoglobin
what is hematocrit
fraction of blood occupied by cells
what is hematocrit usually
3 times hemoglobin
what is purpose of transfusing red cells in massive blood loss
restore blood volume
how many lab measurements is hemoglobin
1
how many lab measurements is hematocrit
2 measurements on hematology analyzer
what are the indications for red cell transfusion
- when patient is symptomatic (increased HR, increased RR, confusion, weakness, dizziness)
- acute blood loss and/ or rapid volume expansion
- during or immediately after acute MI
- clear Hgb trend that you cant yet reverse
what does acute MI mean
the patient has just cut off the blood supply to part of their myocardium, which in turn means that their coronary arteries are, at least in one spot, a bit on the narrow side (or completely occluded). Enhanced oxygen carrying capacity has been shown to improve their clinical outcomes.
when is acute MI mortality increased
hemoglobin less than 10
othrwise healthy patients can tolerate hemoglobin less than
7
what type of patients are usually adapted to low hemoglobin
renal failure
what are mythical indication for red cell transfusion
old and frail patient, asymptomatic coronary artery disease, expand blood volume, promote wound healing
why do cardiologists prefer to transfuse coronary artery disease patients
to keep hemoglbin above 10, but not much evidence to support this
what can hypotensive patients be treated with
expand blood volume with isotonic IV fluids; red cells shoud NOT be used as risks outweigh benefits
what to do for acute blood loss
o neg blood is immed available, typing takes 20 min, screening and crossmatching adds another 20
is anemia a diagnosis
NO
hgb numbers are strict for transfusion purposes True or false
false! some patients functional at hgb=7 some need transfusion at hgb=9
when is plasma transfusion indicated
replace mission plasma protein or multiple ones
what are missing plasma proteins that could need transfusion
- Factor VIII or IX (hemophilias A and B)
- Antithrombin III (rare pro-thrombotic condition)
- AdamTS13 deficiency (TTP*)
what is you ae missing multiple plasma proteins
Coumadin toxicity with bleeding
what is antithrombin III
rare pro thrombotic condition
what is def in hemophilia b
factor IX
what is def in hemophilia a
factor VIII
what is adamts13 def
TTP
what are indications for platelet transfusion
treat ongoing hemorrhage in thrombocytopenic patient( less than 50), prevent hemorrhage in severe thrombocytopenic patient (less than 10), treat or prevent hemorrhage in patient with dysfunctional platelets (patients who have undergone cardiopulmonary bypass, patients treated with irrev platelet inhibiting drugs)
if a patient has been on nsaids within a few days of a current uncontrolled bleed, they may benefit from….
platelet transfusion
what are the major categories of bad transfusion outcomes
immune response, volume overload, transfusion transmitted infection, graft vs host disease
what are the types of immune responses in transfusions
acute hemolytic reaction, production of antibody to minor red cell antigen, urticarial reaction to transfused plasma proteins, febrile reaction to transfused leukocytes
what is seen in acute hemolytic reaction
fever, chills, chest pain, hypotension, nausea, flushing, dyspnea, hemoglobinura (in order from most common to least)
what are possible clinical outcomes of acute hemolytic reaction
renal failure and death
what makes a patient more likely to develop anitbody to minor antigen on rbc
already formed antibody, poorly defined antibody former, sickle cell patients (extended crossmatch should be standard of care)
what is compatibility standard for most patients
ABO, rh
what is compatibility standard for sickle cell patients
abo, rh, RhCE, K compatible
Red cells are mostly plasma free, but not entirely so. what can patients suffer from if develop reaction to plasma proteins
urticarial reaction
how do you treat febrile reaction to transfused leuokcytes
tylenol
what do you do if patient dev fever after transfusion
EXAMINE to make sure no other symptoms of acute hemolytic reaction are present
what is patient’s normal blood volume
4.5 to 5 L
2 units of red cells can increase patients volume by
10% - this can be a problem with heart disease patients - cannot handle extra cardiac load
how common are transfusion infected infections
1 in 100,000!!!!! RARE
how do we minimize transfusion infected infections
donor screening: questionnaire, multiple criteria for deferral (travel to malaria places, IV drug use, confidential self exclusion); serum tests for infectious agents (HIV, HCV, HBV)
what is graft vs host disease
immune response of transfused leukocytes against recipient tissues, rare unless patient is immunocompromised
how do you minimize risk of graft vs host
always use leukoreduced red cells for immunocompromised patients; can reduce risk to 0 by using irradiated cells
what is a consequence of graft vs host
sloughing of epithelial cells in GI tract
