Cross Species - Coagulation Panels & Blood Transfusions Flashcards
what is primary hemostasis?
formation of the platelet plug
what test evaluates platelet function? when is it done? what is a normal value?
BMBT - only done if platelet count is normal, normal is under 4 minutes
what are some examples of how platelet abnormalities manifest as clinical signs?
mucosal bleeding, epistaxis, scleral hemorrhage, gi bleeding, gingival bleeding, petechiation, & ecchymoses
what are some common diseases that cause platelet abnormalities?
canine ITP, VW disease (most common inherited bleeding disorder in dogs)
what is secondary hemostasis? what pathways are involved?
formation of fibrin clot via coagulation factors - extrinsic, intrinsic, & common
what factors are included in the extrinsic pathway? what testing is involved in this pathway?
factor VII & tissue factor - prothrombin time, PT
what factors are included in the intrinsic pathway? what testing is involved in this pathway?
factors XI, IX, XII, VIII - activated partial thromboplastin time, PTT
what factors are involved in the common pathway? what testing is involed in this pathway?
factors II, X, VIII, V, fibrinogen - tests aPTT & PT
what factors are vitamin k dependent?
II, VII, IX, & X
what is ACT? what does it assess?
activated coagulation time - assess all pathways but less sensitive & more subjective
what are some reasons you may have abnormal results due to spurious error?
traumatic blood draw or underfilled tube
what testing is most often done to get the most complete picture when assessing coagulation? what is it performed on?
typically run PT & aPTT together
what are some common causes of hemoabdomen/hemothorax?
anticoagulant rodenticide toxicosis, congenital factor VIII deficiency (hemophilia a), & hepatic failure
why is PT prolonged prior to aPTT in rodenticide toxicity?
factor VII has the shortest half life of the vitamin k dependent factors, so it is depleted first
what is fibrinolysis? what proteins are involved?
clot breakdown - tissue plasminogen activator & plasminogen
what testing can be done to assess fibrinolysis?
fibrin-degredation products, d-dimers, & thromboelastography - provides global assessment of blood clotting abnormalities
what are some diseases that can cause pathologic thrombosis in small companion animals? why?
PLN in dogs, early stages of DIC, colic, & laminitis in horses - pathologic thrombosis occurs due to loss of anticoagulant factors or an excess of procoagulant factors
what determines blood type?
specific antigens on red blood cell surface - antigen & typing are species specific
what are the two types of antibodies to red blood cell antigens?
naturally occuring - present in blood without prior transfusion exposure & acquired - following RBC antigen exposure
what are the major blood types in dogs? what do you commonly test them for?
DEA types 1-8 - test for DEA 1.1 positive or negative
what blood type in dogs is the universal donor? how does this work for first time transfusions?
DEA 1.1 negative are universal donors - suitable for DEA 1.1 negative & positive - yes even for first time
when may an acute hemolytic reaction be seen in a dog receiving a blood transfusion? why?
can occur in DEA 1.1 negative if dog was sensitized by previous transfusion - naturally occuring antibodies to RBC antigen does not exist, so cross match is not required before the first transfusion but must be done prior to all subsequent transfusions
what blood typing is used in cats? which is more common?
AB system - most are type A
what cats are typically type b?
purebred cats - devon rex, cornish rex, bristish shorthairs
why is cross matching & blood typing in cats necessary? even at first time transfusion?
other RBC antigens & naturally occuring antibodies are not detected by blood typing!!!!! they have naturally occuring antibodies to the other blood type antigen
T/F: never give type a blood to a type b cat
TRUE
is there a universal blood donor type in cats?
no - but type AB cats can receive type A or B blood because they don’t have antibodies to either type but they are rare
when can neonatal isoerythrolysis occur in cats?
if type A or type AB kittens are born to a B queen mated to a type A tom
what are the equine blood types?
7 recognized types - A, C, D, K, P, Q, & U
what blood types are most important for neonatal isoerythrolysis & hemolytic transfusion reactions in horses?
Aa & Qa
why are first transfusions without cross matching in horses usually safe?
less than 10% of horses have naturally occuring alloantibodies
how many blood groups do cattle have? why is matching difficult?
11 major groups - b group has multiple antigens making close matching of donor & recipient difficult
T/F: neonatal isoerythrolysis doesn’t occur naturally in cattle
TRUE
how many blood groups do sheep have? goats?
sheep - 7, goats - 5
T/F: some cattle vaccines may contain RBC antigens and can cause antibody formation without a blood transfusion
TRUE
when is cross-matching usually done?
done after typing in dogs & cats to determine blood transfusion compatibility
what are the two types of cross matching? which is most important? why?
major - donor RBC + recipient serum to determine if the recipient has preformed antibodies to donor RBC antigens & minor cross match where the donor serum + recipient RBC to determine if donor has preformed antibodies to recipient RBC antigen
when is a cross match performed in cats?
before the first & every subsequent transfusion because they have naturally occuring antibodies
when is a cross match done in all other species?
after the first & every subsequent transfusion because antibodies are induced by exposure to foreign RBC
how is a major cross match performed?
wash RBC 3 times to remove substances that can cause agglutination, mix RBC with serum & assess for agglutination
microscopic or macroscopic agglutination & macroscopic hemolysis particularly in horses indicates what?
incompatible transfusion
when is a minor cross match performed?
only done in small animal patients receiving significant volume of plasma - donor antibodies to recipient RBC antigen are usually diluted enough to not be of significant concern
what is a mare-foal, mare-stallion incompatibility test?
cross match done to assess incompatibility to determine risk of neonatal isoerythrolysis - assess antibodies in mare serum to RBC antigen of the foal or stallion
