Transfusions Flashcards
What are the main differentials for regenerative anaemia?
■ Haemolytic disorders (causes/triggers)
● Infectious (viral, bacterial, parasitic)
● Immune disorders (IMHA, systemic lupus erythematosus, hypothyroidism, immunodeficiencies)
● Drugs (vaccines, sulphonamides, methimazole,
procainamide, cephalosporins, penicillins, propyluracil)
● Oxidants (paracetamol, phenothiazines, vitamin K, methylene blue, methionine, propylene glycol)
● Neoplasia
● Genetic predisposition
■ Haemorrhage
What are the main differentials for non regenerative anaemia?
■ Preregenerative anaemias
■■ Anaemia of chronic inflammatory disease
■■ Iron-deficiency anaemia
■■ Bone marrow disorders
■■ Infections (viral, mycoplasma, ehrlichiosis, babesiosis)
■■ Drugs (chemotherapy, immunotherapy)
■■ Myelofibrosis
■■ Myelopthistic disease (neoplasia)
■■ Myelodysplasia
■■ Pure red cell aplasia
■■ Ineffective erythropoiesis (deficiencies in
erythropoietin, vitamin B12, folic acid, globins
or porphyrin)
When should transfusions be performed?
No set line - risk v benefit
■ A patient is exhibiting significant clinical signs of
anaemia;
■ An animal has a PCV of less than 10 per cent;
■ An animal’s PCV has fallen rapidly to less than 20
per cent in dogs or 15 per cent in cats.
In patients with a poor or absent bone marrow
response, red cells are unlikely to be replenished in the short term and, hence, earlier transfusion may be indicated in order to prevent further clinical compromise
What is the use of fresh whole blood?
Fresh whole blood contains red blood cells, all clotting
factors, plasma proteins and anti-inflammatory proteins, with a small number of platelets. Whole blood can therefore be used in many conditions, including
acute or severe haemorrhage, haemolytic anaemia,
chronic blood loss or non-regenerative anaemia, and
coagulopathies if other blood products are not available. Whole blood must be used within four to six hours of collection to maximise its full range of benefits.
What is the use of stored whole blood?
Stored whole blood is fresh whole blood collected into
an appropriate bag (usually one designed and used
in human medicine) that contains an anticoagulant
(eg, citrate phosphate dextrose adenine-1 [CPDA-1]).
Whole blood can be stored in a refrigerator at 1 to 6°C
for up to 28 days. However, after 12 to 24 hours, many
plasma proteins will be degraded, making the product
ineffective in conditions requiring coagulation factors.
As a rule of thumb, 2 ml/kg of whole blood will
raise a recipient’s PCV by 1 per cent or the haemoglobin level by 0·3 g/dl.
What is the use of pRBCs?
A unit of canine packed red blood cells is
about 200 to 250 ml and has the same oxygen carrying capacity as one unit of whole blood (450 ml)
As packed red blood cells contain only a
small amount of plasma, they have a minimal effect on
oncotic pressure - may therefore be safer in those prone to volume over load
As a rule of thumb, 2 ml/kg of packed red blood
cells will raise a recipient’s PCV by 2 per cent or the
haemoglobin level by 0·6 g/dl.
When is Fresh Frozen Plasma good?
Fresh frozen plasma is generally indicated for animals with inherited and acquired coagulopathies and in patients with prolonged clotting times undergoing invasive procedures (eg, liver biopsy). It can be used for some plasma protein deficiencies (eg, immunoglobulin) and may be useful in providing antiparvovirus antibodies and immunoglobulins in cases of parvovirus infection, although conclusive evidence is lacking.
What is Frozen plasma?
Frozen plasma has lost the action of many clotting factors (V, VIII, von Willebrand factor [vWF]) and plasma proteins, but it still contains vitamin K-dependent
factors (II, VII, IX, X).
Frozen plasma has either been frozen more than six
hours after collection, has been thawed and refrozen,
or has been frozen beyond the recommended maximum storage time (see above). This product can be used in patients with deficiencies of the non-labile
clotting factors (eg, anticoagulant rodenticide toxicity
and some plasma protein deficiencies).
What is cryoprecipitate?
Cryoprecipitate is made up of approximately 20 per cent fibrinogen, 50 per cent clotting factor VII and 30 per cent clotting factors VIIIc, XIII and vWF. It is separated from the plasma fraction of blood using a process of controlled thawing and centrifugation. Cryoprecipitate must be stored frozen at –18°C and is stable at this temperature for up to one year. It can be used in patients with inherited clotting factor deficiencies such as haemophilia A and von Willebrand’s disease.
What is cryosupernatant?
Cryosupernatant is the plasma that remains following
separation of the cryoprecipitate as described above.
It is a source of all coagulation and plasma proteins,
except for clotting factors VII, VIIIc and XIII, fibrinogen and vWF. When stored at –18°C, it is stable for one
year. Cryosupernatant can be used for the treatment of
most clotting factor deficiencies, except haemophilia A
and von Willebrand’s disease, and can also be used for plasma protein deficiencies.
What is oxyglobin?
sterile haemoglobin based oxygen-carrying solution made from bovine haemoglobin.
It is only licensed in dogs with anaemia, but its use in cats has been reported.
potent colloid and must therefore be used with caution in patients with cardiorespiratory or central nervous system diseases, or those with oliguric renal failure. Oxyglobin should also be used with care in cats due to the risks of volume overload and possible pulmonary bed vasoconstriction.
Following administration, Oxyglobin causes discoloration of the mucous membranes, sclera and urine, making clinical assessment difficult. It also interferes with some biochemical analysers.
Most gone within a week of use
Outline canine blood types
** whelping should be considered a whelping event**
eight different blood groups have been recognised in the dog, with the major and most immunogenic being DEA 1.1 for which dogs can be either positive or negative.
The others include DEA 1.2, DEA 3, DEA 4, DEA 5, DEA 7 and a new antigen in dalmatians called DAL.
DEA 1.1 is the most common blood type in dogs and, although naturally occurring antibodies to DEA 1.1 are rare, the determination of DEA 1.1 antigen is strongly recommended as this antigen is highly immunogenic and will result in antibody formation.
The antigen to DEA.1.1 is not naturally occuring so should be fine for the first transufsion, sensitisation takes 2-4 days. Naturally occurring antibodies against DEA 7 are present in 15 per cent of dogs, but DEA 7 antigen is rare. These antibodies may be responsible for
the occasional mild reactions following first transfusions.
Outline feline blood types
Cats have three main blood types (on the AB system),
which are type A, B or AB. The antigens associated with these types are highly immunogenic and type B cats have high levels of naturally occurring antibodies. This means that fatal transfusions can occur with even tiny volumes of incompatible blood (Callan and Giger 1994).
Although type AB cats have no naturally occurring
antibody, they posses both A and B antigens and donor blood from these animals can therefore cause a significant reaction in recipients, as their cells are susceptible to destruction by antibodies in the donor plasma.
Type A cats possess only low titres of anti-B antibodies and so the transfusion of incompatible blood to
type A cats only results in a mild reaction with minimal
clinical signs
How much blood can an animal donate?
Dogs and cats can donate 10 per cent of their total
blood volume with no adverse effect (blood volume =
66 ml/kg in cats and 90 ml/kg in dogs [Turnwald and
Pichler 1985]). Collection of 20 per cent of blood volume should not result in clinically significant anaemia provided the donor has a normal PCV at collection, although it can produce hypovolaemia in the short term.
Collection of >20 per cent of blood volume can produce hypovolaemia of sufficient magnitude to compromise health
What do you normally collect canine blood in?
human blood collection bag which contains enough
acid citrate dextrose (ACD) or citrate phosphate dextrose (CPD) anticoagulant for approximately 500 ml
of blood.
