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27 Cards in this Set
- Front
- Back
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What are blood types due to? Why might there be an immune response to them?
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-blood type is due to a specific antigen present on the external surface of the red blood cell membrane
-if the animal's own RBCs do not have the surface antigen present and you put some of that blood into their bodies then they will react against it and make antibodies against it -the next time the animal's body sees the RBCs bearing the same foreign antigen then antibodies will try to destroy or remove the RBCs (a type II hypersensitivity) -BUT if there are naturally occurring antibodies already present (as in cats & people) then you can get an immunological reaction to a first transfusion |
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What are the most important canine blood types with respect to transfusion and why?
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-DEA 1.1. has the most severe transfusion reaction
-in dogs there are no naturally occurring antibodies so first transfusion will never cause an immune reaction -if you give DEA 1.1 positive blood to a DEA 1.1 negative dog then the recipient's immune system will recognize the DEA 1.1 antigen as foreign and make antibodies against DEA 1.1 (takes minimum 4-5 days to up to 2 weeks) -BUT if you give this dog another DEA 1.1 positive transfusion then the dog will have a severe haemolytic reaction as the antibodies attack transfused cells -better to give DEA 1.1 positive blood to only a DEA 1.1 positive dog -DEA 1.2 is the next most important with respect to antigenicity and reactions -if you give a DEA 1.2 positive blood to a DEA 1.2 negative dog that had been previously given a 1.2 positive transfusion then this is just going to cause the 1.2 positive cells to be removed from circulation rather than a severe hemolytic reaction |
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How do we test if a dog is DEA 1.1 positive?
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Use typing cards that have antibody to DEA 1.1 on them
-if the patient's blood contains the DEA 1.1 antigen then the blood will agglutinate on the patient test area and the positive control area -the area marked autoagglutination saline screen is to test for autoagglutination that is already present in the blood sample because if it has already autoagglutinated then the cards are useless |
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If we have previously given a dog who was DEA 1.1 negative a transfusion how do we tell if the dog has been sensitized to another blood type?
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-mix the recipient's plasma (where antibodies will be) with donor RBCs (where antigens will be) → MAJOR CROSS MATCH
-minor cross match → mix donor plasma with recipient's RBCs -there will only be antiobodies if the donor had received a previous transfusion -no need to cross match if donor & recipient NEVER received a transfusion |
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If you see clumping of RBCs on a slide what should you do?
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-examine it under a microscope to make sure that it is really agglutination
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What blood types are there in cats? What types are common?
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3 blood types: A, B, and AB (not a mixture of A & B but a separate blood type)
-A is the most common blood type but how much more common depends on where in the world you are -B is rare in the US, uncommon but present in the UK and common in Australia (40% of cats) |
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What blood type is the worst transfusion in cats?
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-type B cats have pre-existing, very strong anti-A antibodies so you can kill a type B cat by giving it type A blood
-type A blood to a B cat leads to a very severe transfusion reaction and possibly death (30%) -give type B blood to an A cat is usually not life threatening but the cells just don't last very long -all cats must be types prior to transfusion |
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What is neonatal isoerythrolysis in cats?
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-occurs when a Type A kitten is born to a Type B queen
-the antibodies don't cause a problem in utero because the antibodies do not cross the placenta BUT when the kittens are born and ingest colostrum they take in the strong anti-A antibodies which then cause hemolysis |
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What do we look for in canine donors?
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-good temperament
-easily accessible jugulars -no other health problems -vaccinated >25 kgs to allow collection of full unit (450 mL) -negative for blood borne diseases in your area -should never have received a transfusion -ideally DEA 1.1 negative |
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What do we look for in feline donors?
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>5 kg body weight
-no other health problems -FeLV/FIV/Mycoplasma negative -ideally indoor cat -donors of both blood groups required |
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What do we do to our patients or check for prior to collection? How do we collect the blood?
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-donor should receive a physical examination prior to each donation
-animals that are pyrexic or unwell should not be used -PCV of donor should be checks → if anemic do not use →animals should be able to donate up to once monthly without becoming anemia CLOSED: -proper blood collection technque because there are no breaks in the lines and bags during collection and processing -blood is initially drawn (by gravity or suction) into a bag that has a satellite bag already attached that will recieve the plasma when it is separated OPEN: -use multiple syringes to draw the blood -blood drawn this way must be used immediately to avoid possibility of bacterial proliferation in the blood |
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What anti-coagulent do we use for blood? What else do we add to the blood? Why is Heparin not added?
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-best anticoagulant/preservative mixutre is CPDA-1
-the C is the anticoagulant citrate, which acts by binding calcium which is essential for clotting to occur -phosphate dextrose and adenine are substance that red blood cells need to stay alive longer -adenine and phosphate help to maintain ATP levels and dextrose is a substrate for glycolysis ie. RBC food! -2,3 DPG (diphosphoglycerate) levels are also better maintained with this solution -2,3 DPG is found in RBCs and helps hemoglobin to release oxygen so having higher levels is a good thing -heparin is not used because it can make the recipient coagulopathic and activate platlets -blood can be stored with CPDA-1 for 35 days |
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What is component therapy?
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-component therapy is separating fresh whole blood into its constituent parts to allow us to get more out of each unit and to only give the patient what they need
-fresh whole blood is first separated into packed red blood cells and plasma (via centrifuge) -the plasma is usually then immediately frozen to give fresh frozen plasma -the line of the bag has blood left in it which is crimped into smaller segments that are used for cross matching do that the bag doesn't have to be opened |
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How do we administer blood?
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-blood must be filtered to remove microscopic clots and platelet clumps so a special giving set is used with a filter to remove them
-other filters can be used to remove leukocytes in an attempt to reduce the likelihood of transfusion reactions |
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What is fresh whole blood? stored blood? autotransfused blood?
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❤Fresh Whole blood:
-has everything in it (ie. RBCs, plasma proteins, all coagulation factors & some functional platelets) ❤Stored whole blood -has RBCs, plasma proteins, and the stable coagulation factors (II, VII, IX, X) BUT NOT PLATELETS -it is still ok for anticoagulant rodenticide toxicity -most labile factors are 5 & 8 ❤Autotransfusion -is taking blood from a body cavity and putting it back into a vein -it will contain CLOTS so use a filter -only appropriate as a rescue measure ie when blood is not available -really only used when you can in surgically and physically arrest the hemorrhage you are trying to stop or when you are already in surgery and have catastrophic bleeding |
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What are the indications for whole blood?
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-the main indication for using whole blood is when the animal needs RBCs and plasma
-the main situations are: ❤Severe hypovolemia due to rapid loss of whole blood ❤When coagulopathy is coupled with anemia -more than 30% blood volume is given -in most situations it is fine to volume replace an animal with crystalloids first, then re-evaluate whee you are with the PCV |
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What are the indications of packed red blood cells?
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-main indication is when the animal is anemic but still has a normal or near normal blood volume as evidence by cardiovascular perfusion parameters being normal
-euvolemic anemia may occur with decreased RBC production by the bone marrow, hemolysis and from low grade bleeding (ie low grade GI bleeds or fleas) -start thinking about transfusion when the PCV falls below 20% and always try to keep PCV over 15% |
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What are the indications for fresh frozen plasma?
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-fresh frozen plasma contains everything that plasma does ie. clotting factors, antithrombin and anti-inflammatory proteins
-main clinical use is to provide clotting factors ❤ANTICOAGULANT RODENTICIDE INTOXICATIONS that are actively bleeding -give 20 mL/kg ❤also can be used in treatment of inflammatory conditions such as all the things that cause the systemic inflammatory response syndrome (SIRS) -that in warm water not >50 oC or proteins could denature |
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What is the use of stored frozen plasma?
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-stored plasma means fresh frozen plasma that has been defrosted for one patient and not used and then refrozen
-the vitamin K dependent factors are still ok, so you can refreeze it and use it for anticoagulant rodenticide toxicity in the future |
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Why don't we give plasma in chronic hypoproteinemia?
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-because albumin equilibrates with the extracellular space over time and you need gallons of the stuff to increase albumin concentration
-need as much as 100 mL/kg to raise albumin by 10 g/L |
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Is it worth making platelet rich plasma?
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-prepared by slow centrifugation of fresh blood at a warm temerature
-has to be prepared & used withing 5 days -need multiple FWB unite to make 1 of PRP -NO, it takes so many donors and so much effort that it's just too hard to justify using it when you are going to pour it into a dog with ITP or DIC |
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What is cryoprecipitate and what is it used for?
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-is prepared from fresh frozen plasma and involves thawing it to a slush and then separating it
-it can be stored for up to a year ❤Reserved for treatment of bleeding von Willebrand disease or dogs with vWD undergoing surgery -but most of the time we give them fresh frozen plasma because it has von Willeband factor and is cheaper & available -also give the desmopressin to increase vWF |
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What non-immune transfusion reactions can occur?
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-hemolysis of transfused cells (due to mechanical trauma, overheating, freezing, or poor storage), bacterial contaminattion, citrate toxicity and ionised hypocalcemia, dilutional coagulopathy, disease transmission and circulatory overload
-to make sure sample is in good shape, spin it down and check if serum is not haemolyzed |
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What immune transfusion reactions can occur? What are the clinical signs?
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❤ACUTE:
-acute, immune mediated transfusion reaction results in: *rapid hemolysis of transfused RBCs and anaphylactic shock and systemic vasculitis -signs include: *pyrexia, tachycardia, tachypnoea, salivation, vomiting, tremors, facial swelling, collapse -most transfusion reactions are self limiting -can check if animal is having a transfusion reaction by spinning down a PCV tube and looking if serum is hemolysed -more reactions occur to plasma than to RBCs (type I hypersensitivity - facial swelling, pruritis) ❤Delayed -very difficult to spot BUT you will see a drop in PCV 2-21 days post transfusion ie. red cells have been destroyed more quickly than expected |
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How do we treat transfusion reactions?
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-stop the transfusion
-give intravenous fluid therapy -intravenous corticosteroids (dexamethisone SP 0.4 mg/kg) -intravenous antihistamines -supportive care as necessary |
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What are the transfusion protocols?
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-all transfusions should be started slowly (2-5 mL/hour total rate for 20 mins) to allow early recognition of the transfusion reaction before it becomes life threatening (the first signs we see of a transfusion reaction are usually pyrexia, salivation, tachycardia, tachypnea, vomiting or facial swelling)
-the remainder of the blood should be given over 4-6 hours but do not volume overload them |
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When do we transfuse?
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-if the animal is hypovolemic as opposed to euvolemic you will transfuse sooner rather than later
-if the loss of blood is acute then the patient has not had time to compensate for the low red blood cell levels so it would need a transfusion at a higher PCV than an animal that has chronic anaemia ❤PCV 30% → if you want to have the best tissue oxygen delivery keep the PCV at 30% ❤PCV 20% → might start to get compromised tissue oxygen delivery so hart will have to work harder & increase CO -so if you don't want heart to work harder keep PCV above 20% ❤PCV 15% in a euvolemic dog with acute anemia → lactate increases due to anaerobic tissue metabolism -so if you don't want to wait until the tissues are definitely in trouble then transfuse them when their PCVs are <15% |
