Health News
Canine Blood Transfusions
Uncovering the Facts
By Debra Ball

Doctor Kate Hsuen-Wen Chang of the University of Melbourne has
developed a method for identifying blood type in the dog.1   The
importance of this discovery has far reaching implications especially in
the area of blood transfusions.  We might, therefore, ask is it
dangerous for my dog to have a blood transfusion?  Where do
veterinarians normally get canine blood for transfusions? Should my
dog become a blood donor?  There are a number of situations that
might occur where your beloved pet might need a transfusion, an
encounter with a moving vehicle comes readily to mind, but also, some
types of chemotherapy may leave your pet in need of a blood, and
complications after surgery may require a transfusion.  What do you,
as a responsible pet owner, need to know in order to make an informed
decision about this procedure?

What role does blood play in the body?  According to the National
Space Biomedical Research Institute “blood is unique…the only tissue
in the body that flows”.  Blood is composed of two parts. Plasma, the
liquid part, makes up 55% of blood volume. The cellular portion makes
up the other 45%.  Plasma is composed of 91% water.  Hormones,
proteins, nutrients, and chemicals make up the other 9%.  The cellular
portion of blood contains white blood cells (leukocytes), red blood cells
(erythrocytes), and platelets.  Leukocytes leave the bloodstream and
move throughout the body to attack bacteria, viruses, and parasites.  
They either consume the invader or destroy it by synthesizing
antibodies, which attack it. 2   Whenever the white blood cell count
goes up, there is a strong possibility that the body has been attacked.  
Red blood cells carry oxygen and platelets help in blood clotting.  
Blood is indeed unique and the only organ without which the body
cannot function. No substance whether organic or mechanical can
replace the blood in the body and the organism continue to live.

Dogs do indeed have blood types, in fact they have from eight to
twelve types whereas we humans have only four, O, A, B, and AB.   
Canine blood types are called Erythrocyte Antigens (DEA).  Just as our
blood type can be followed by a + or -, your dog’s DEA is followed by
numbers such as DEA 1.1 positive or negative.  And just as type O is a
universal donor in humans, dogs with type DEA 1.1 negative can be
universal donors.  Blood types are determined by examining the
antigens found on the surface of red blood cells. Antigens are foreign
substances, which trigger the production of antibodies.  These
substances can be foreign blood cells, toxins, or bacteria.  Antibodies
can be of two types, those that naturally occur in the body and those
that are produced as a result of being given an incompatible blood
type.  This can occur through blood transfusions or through
vaccinations, which contain red blood cell antigens.3

Associate Professor Ian Walker of the University of Melbourne says
that dogs can safely receive one blood transfusion but afterwards, they
may develop antibodies to other dog’s blood type.4  In other words, the
body views the donor blood as an invader. Hemolytic reaction
(destruction of red blood cells) can occur when a dog receives the
wrong blood type. Red blood cells carry oxygen to the body. Oxygen is
vital in metabolism, the detoxification of cells, and in its antimicrobial
properties.   Recent studies have found that “infection-fighting cells
take oxygen, convert it into a type of free radical, and inject those
substances into bacteria to destroy them.”5 If your dog is in an already
compromised condition due to injury or illness, a breakdown in the red
cell structure could prove fatal. Fortunately, “acute hemolytic
transfusion reactions only occur in DEA 1.1 and 1.2 negative dogs.”6

Transfused red blood cells live about 21 days; however during a
hemolytic reaction the red cells will begin dying within 12 hours. This
can result in hemoglobinemia (free hemoglobin in the blood stream),
disseminated intravascular coagulation, cardiovascular collapse, renal
failure, and death.7 Dogs, given an initial blood transfusion, may not
develop a hemolytic reaction, but a subsequent one, can prove fatal;
therefore, any dog that has been exposed to blood group antigens,
either through a transfusion or through vaccination, should be cross
matched to ensure that they are given compatible blood in the future.
There is currently no reliable method for assessing blood type in the
dog.

Non-oxygen-carrying substitutes for blood (called volume expanders)
are available.  Substances such as Ringer’s lactate expend the blood
volume and are effective treatment for blood lose of 50% or less.  This
allows the remaining red blood cells to circulate freely through the
body; however, when the blood loss reaches 30% or more, the
question is no longer one of circulation alone, but the capacity of the
remaining red blood cells to carry enough oxygen to the vital organs.  
Hemoglobin, the protein to which oxygen bonds, is what needs to be
replenished and no reliable substitute for blood has yet been
developed.

Long-term use of blood transfusions can also prove fatal. One problem
associated with long-term use of blood transfusions is increased iron
overload disorders.  In an article in Veterinary Pathology, W.S.
Sprague, T.B. Hackett, J.S. Johnson, and C. J. Swardson-Oliver
reviewed the case of a Miniature Schnauzer who was diagnosed with
hemochromatosis (organ dysfunction secondary to iron-induced injury)
after receiving transfusions over a three year period.8  Blood
transfusions, while being life saving, are not without their risks and
responsible owners should explore all their options.

Today a number of organizations exist for the collection, maintenance,
and distribution of blood products to the veterinary world.  Still, most
Veterinarians use dogs owned by themselves or their staff as blood
donors.  Human blood banks are big business, Gilbert M. Gaul,
Philadelphia Inquirer, Staff Writer stated in an article entitled The Blood
Brokers: How Blood, The “Gift of Life” Became A Billion-Dollar Business
that what blood donors don’t realize is that the same month one blood
bank was appealing for blood, it sold 650 pints at a profit to other blood
banks.  Human blood banks profit from as much as fifty million dollars
per year from donated blood.9 Since just like human blood banks,
many canine blood centers rely on volunteers donors, it behooves the
altruistic pet owner to research the pros and cons of blood donation
before proceeding.

Dogs’ chosen as blood donors must be healthy, up to date on
vaccines, and heartworm free.  They cannot have had a blood
transfusion or a serious illness.  Most programs require the dogs to be
between the ages of one and seven and weigh at least fifty pounds.  
The dog should be a universal donor with a blood type of DEA 1.1
negative.  They’ll be tested for diseases such as Rocky Mountain
Spotted Fever and Lyme Disease and will need a complete blood
workup. Donor dogs start to recover blood volume immediately but it
can take up to three weeks for the red cell count to return to normal.

Besides the satisfaction of knowing you have helped other dogs in
need, what can you expect for your dog’s donation?  Rewards range
from “treats and belly rubs” as The Pet Blood Bank of Texas states, to
toys, free veterinary care, and even monetary compensation.10  We
would like to think that the giving of blood is solely for the saving of
lives, but the bottom line may be the bottom line, so do your research.  
If this is something you would like to get in involved with, then contact
your veterinarian.  He or she may offer free services to their clients
who chose to donate blood, such as annual heartworm tests.

Blood is life sustaining, but it can also be life threatening.  Do your
homework before an emergency arises.  Find out if your veterinarian
keeps donor dogs on hand or if they bank blood.  Have your doctor
type your dog the next time you are doing routine blood workup.  Also,
when switching clinics, make sure you inform your new veterinarian that
your dog has had a previous blood transfusion.  Before agreeing to
long-term use of blood, learn the facts.  Ask questions.  Don’t be afraid
to seek a second opinion.  Your dog’s health may depend upon it.
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