Blood Transfusion Flashcards
what changes have the RCVS made to make blood products widely available for primary care small animal practitioners?
taking of blood from healthy donors with the permission of the owner with the intention of passing it to a recipient with immediate or anticipated need
VMD licensed blood banks
what blood products are available for dogs in the UK?
whole blood packed red blood cells (PRBCs) fresh frozen plasma frozen plasma cryoprecipitate cryoprecipitate poor plasma
what blood products are available for cats in the UK?
no feline per blood banks
whole blood can be obtained locally
how can whole blood be obtained for cats?
locally via:
local donor colonies
cats of consenting colleagues, clients, friends and family
donors from local animal register
why can more be done with canine blood than with feline blood?
canine blood can be collected in advance and so can be processed much more easily
this enables it to help more patients
what is produced by a hard spin in a centrifuge of whole blood?
packed RBC (precipitate) fresh frozen plasma (supernatant)
what is fresh whole blood?
blood used within 6 hours of collection
what is found within fresh whole blood?
physiological concentrations of RBC
some functional platelets
proteins
coagulation factors
how must fresh whole blood be stored?
at room temp
what is the PCV of fresh whole blood?
~40% (as normal)
what is stored whole blood?
blood over 8 hours old
how can stored whole blood be stored?
2-6 degrees C
up to 21 days
what is found in stored whole blood?
no functional platelets
loss of labile clotting factors
what are labile clotting factors?
factor 8
VWF
how are packed red blood cells separated from plasma?
by centrifugation
what is the PCV of packed red blood cells?
higher than that of whole blood (70-80%)
how should PRBCs be stored?
2-6 degrees C
42 days
how is fresh frozen plasma stored?
-18 degrees
less than 1 year
what is found in fresh frozen plasma?
all coagulation factors (including labile)
physiological concentrations of albumin and other plasma proteins
what is frozen plasma?
FFP that is >1 year old or that has been thawed and refrozen either intentionally or by accident
what is found in frozen plasma?
stable coagulation factors
labile factors lost
how is FP stored?
below -18 degrees for up to 5 years
ho is cryoprecipitate made?
by slowly and partially thawing FFP which is then centrifuged again
cryoprecipitate is collected from second centrifugation
what is found in cryoprecipitate?
fibrinogen
VIII
vWF
(labile clotting factors)
what patients may benefit from transfusion therapy?
those with diseases that result in a deficiency of a blood constituent may benefit from transfusion
what are some examples of diseases which may benefit from transfusion therapy?
hypovolaemic anaemia (e.g. blood loss) euvolaemic anaemia (e.g. IMHA) coagulopathies (e.g. rodenticide toxicity)
is transfusion therapy helpful for thrombocytopenia, thrombopathia or hypoalbuminaemia?
unclear
it is often tried but expensive and rarely effective in curing the problem
volume overload is likely before issue is corrected
when are blood products indicated for anaemic patients?
if there are clinical signs of anaemia (i.e. patient is not compensating for the anaemia)
is the decision to use blood products based on PCV values alone?
no
what are the clinical signs of anaemia?
weakness
tachycardia
tachypnoea
indirect measures of poor oxygen delivery (e.g. high blood lactate)
what product is the ideal one to use for transfusion?
most closely replaces that which is missing
what is the benefit of using the blood product that most closely replaces that which is missing?
reduces the likelihood of transfusion complications
allows blood products to be used most effectively
when does blood type need to be considered?
if giving whole blood or PRBCs
how are antibodies for RBC acquired in dogs?
may be naturally occurring or acquired through previous sensitisation
how do dogs gain antibodies to RBC through sensitisation?
due to a previous blood transfusion
what happens if the recipients RBC antibodies match antigens on the donor RBC?
immune response leading to immune mediated transfusion reaction
what are the signs of transfusion reaction?
fever tachycardia dyspnoea muscle tremors vomiting weakness collapse haemoglobinemia haemoglobinuria
what is the name of the dog erythrocyte antigen?
DEA
wat are the types of DEA that can be found by labs?
1, 3, 4, 5 and 7
within each type of DEA what types are there?
positive and negative
what is the most antigenic DEA?
DEA 1 - most concerning and most common cause of immune mediated transfusion reaction
what is the only DEA we can type for in clinical practice?
DEA 1
do dogs possess naturally occurring antibodies to DEA 1?
no
describe the RBC of a DEA1 positive dog
RBC possesses DEA1 antigen
describe the RBC of a DEA1 negative dog
RBC does not possess DEA1 antigen nor does it’s plasma contain any anti-DEA1 alloantibodies
what are the other main canine blood types?
Dal (positive and negative)
what Dal blood type do most dogs have?
positive
what dogs are Dal negative?
dalmations
can Dal be typed for in house?
no
if giving dalmatians a blood transfusion where should it come from?
ideally from another dalmatian or they need to be cross matched
are there any other blood types in dogs apart from Dal and DEA?
yes but not clinically relevant
what blood should DEA1 negative dogs receive?
only DEA1 negative
what blood should DEA1 positive dogs receive?
either 1 positive or negative