Notes on transfusion medicine

40 Notes on transfusion medicine


There is an increasing availability to nonreferral practices of products for transfusion through commercial and charitable pet blood banks, and a good understanding of the basic principles of transfusion medicine is essential. This is to ensure that the recipient is treated in the safest and most appropriate way, that the owner’s resources are put to greatest use, and that the product which was donated by another animal, sometimes requiring sedation, is in fact used in the most beneficial manner. In the author’s opinion, the latter is sometimes readily overlooked and ultimately it must be remembered that animal blood donors do not volunteer for the task!



Blood Components


Use only the blood product indicated to minimize risk of a transfusion reaction and reduce the total volume to be administered (Table 40.1).



Table 40.1 Summary of main blood components in veterinary use

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Anaemia – normovolaemic versus hypovolaemic



Normovolaemic anaemia



• e.g. chronic nonregenerative anaemia, acute haemolytic anaemia.

• These patients require oxygen-carrying capacity and therefore ideally packed red blood cells (pRBC) only.

• Separation of feline whole blood into components is not commonplace, so cats typically receive fresh whole blood (FWB) transfusion.

• It is often less wasteful to use FWB for small dogs (although smaller or half-units of pRBC may be satisfactory).

• Recipients should be monitored for volume overload.


Hypovolaemic anaemia



• Due to blood loss.

• These patients require both intravascular volume expansion and oxygen-carrying capacity.

• Typically use aggressive isotonic crystalloid or synthetic colloid therapy to correct the hypovolaemia (see Ch. 4), and lower rate FWB or pRBC transfusion for the anaemia.

• Haemoglobin-based oxygen-carrying solutions may have a role in the treatment of hypovolaemic anaemia (see Ch. 4).


Blood Types


These are determined by species-specific inherited antigens on the red blood cell surface.



Canine blood types



• Dog erythrocyte antigen (DEA) 1.1, 1.2, 3, 4, 5, 6, 7 and 8 (plus others); positive or negative for each DEA type.

• DEA 1.1 is extremely antigenic.

• Blood typing is typically restricted to determining DEA 1.1-positive or -negative status.


Clinical Tip



• If blood typing cannot be performed, DEA 1.1-negative blood should ideally be given if available. However, dogs are not believed to have clinically significant, naturally occurring antibodies against foreign red blood cell surface antigens (alloantibodies) and therefore the first blood transfusion between two dogs of opposite blood types is unlikely to cause an acute transfusion reaction. Therefore DEA 1.1-positive blood can be used for the first transfusion if necessary. However, it will induce alloantibody production that may then shorten the lifespan of the transfused red blood cells.

• Once a dog has received a blood transfusion, regardless of whether this was type specific or not, sensitization may occur. It is probably only safe to repeat the transfusion within 4 days before crossmatching becomes essential.


Feline blood types


Routine testing is carried out for blood types A, B and AB.



Type B



• More common among exotic and pure breeds – e.g. British short hair, Devon Rex, Cornish Rex, Abyssinian, Persian, Himalayan, Somali and Maine Coon.

• Most type B cats have high levels of strong, naturally occurring anti-type A alloantibodies (from 2 months of age).

• Severe and potentially fatal transfusion reaction is a very real possibility if a type B cat is given type A blood.


Type A



• The majority are type A.

• A small percentage of type A cats have weak, naturally occurring anti-type B alloantibodies (from 2 months of age).

• A type A cat receiving type B blood is at risk of a transfusion reaction but this should be relatively mild and certainly not fatal.


Type AB



• Relatively rare.

Related posts:

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  2. Shock and dehydration
  3. Pallor and approach to anaemia
  4. Ocular emergencies

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Sep 3, 2016 | Posted by in SMALL ANIMAL | Comments Off on Notes on transfusion medicine

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