Most people have some familiarity with the concept of a
blood transfusion, perhaps by donating blood to the local Red Cross, or
possibly as a recipient during a hospital stay.
Thankfully, most cat owners have very little experience with
transfusions when it comes to their cat.
Transfusions are infrequently performed in general veterinary practice,
however, as cat owners become more willing to pursue state-of-the-art
veterinary diagnostics and therapeutics for their beloved companions, advanced procedures
such as blood transfusions are becoming more commonplace.
blood transfusion, perhaps by donating blood to the local Red Cross, or
possibly as a recipient during a hospital stay.
Thankfully, most cat owners have very little experience with
transfusions when it comes to their cat.
Transfusions are infrequently performed in general veterinary practice,
however, as cat owners become more willing to pursue state-of-the-art
veterinary diagnostics and therapeutics for their beloved companions, advanced procedures
such as blood transfusions are becoming more commonplace.
| Topeka, our hospital cat and blood donor. |
There are several reasons why a cat might require a
transfusion, with anemia (a decreased amount of red blood cells) being by far
the most common. Some veterinary
clinics have a pet “hospital cat” that lives at the clinic and earns its keep
by occasionally functioning as a blood donor in those rare times of need. For years, my hospital employed “Topeka”, a
black and white domestic shorthaired cat who, besides providing us with years
of joy and affection, saved many lives by donating her red blood cells to
desperately anemic fellow felines.
transfusion, with anemia (a decreased amount of red blood cells) being by far
the most common. Some veterinary
clinics have a pet “hospital cat” that lives at the clinic and earns its keep
by occasionally functioning as a blood donor in those rare times of need. For years, my hospital employed “Topeka”, a
black and white domestic shorthaired cat who, besides providing us with years
of joy and affection, saved many lives by donating her red blood cells to
desperately anemic fellow felines.
Blood donors should be healthy adult cats of agreeable
temperament (for easy handling and restraint), preferably in the age range of 2
to 8 years. Ideally, the cat should
weigh 5 kg (11 lbs) or more, be shorthaired, and be of lean body stature. The donor’s PCV (packed cell volume, a
measure of the percentage of the blood that is comprised of red blood cells) should
be greater than 35{9566c0a8c38d7ef68d82188668983429d8c3d2118cd02557d3ef814309ae7d10}. (The normal range for a typical cat is 29 to 48{9566c0a8c38d7ef68d82188668983429d8c3d2118cd02557d3ef814309ae7d10}.) The cat should test negative for the feline
leukemia virus (FeLV), the feline immunodeficiency virus (FIV), toxoplasmosis,
and mycoplasmosis (a red blood parasite).
Blood should not be collected more than once every 4 to 6 weeks from an
individual donor.
temperament (for easy handling and restraint), preferably in the age range of 2
to 8 years. Ideally, the cat should
weigh 5 kg (11 lbs) or more, be shorthaired, and be of lean body stature. The donor’s PCV (packed cell volume, a
measure of the percentage of the blood that is comprised of red blood cells) should
be greater than 35{9566c0a8c38d7ef68d82188668983429d8c3d2118cd02557d3ef814309ae7d10}. (The normal range for a typical cat is 29 to 48{9566c0a8c38d7ef68d82188668983429d8c3d2118cd02557d3ef814309ae7d10}.) The cat should test negative for the feline
leukemia virus (FeLV), the feline immunodeficiency virus (FIV), toxoplasmosis,
and mycoplasmosis (a red blood parasite).
Blood should not be collected more than once every 4 to 6 weeks from an
individual donor.
In a general practice setting like my own, transfusions areperformed using whole blood, because that’s what we obtain from Topeka, our
donor. However, the ability to
fractionate whole blood into its component products has made it easier to treat
a variety of conditions if a blood donor isn’t readily available. Veterinarians now have access via veterinary
blood banks, local emergency clinics, or referral centers, to fresh or stored whole
blood, packed red blood cells (pRBCs), fresh-frozen plasma (FFP), and platelet
products.
Blood is sterilely collected into commercially prepared
blood bags containing an anti-coagulant.
The blood can be used immediately, or it can be stored in a refrigerator
for several weeks until needed. As noted
above, fresh whole blood can also be separated into its component parts. Whole blood contains everything: red blood
cells, serum proteins, clotting factors, and platelets. Because the most common reason for a
transfusion is severe anemia, packed red blood cells (pRBCs) may be a more
appropriate product. The advantage of
using pRBCs is that you are administering the same amount of red blood cells as
that found in a unit of whole blood, but it is in a much smaller volume, making
it safer for animals with concurrent heart or kidney disease.
blood bags containing an anti-coagulant.
The blood can be used immediately, or it can be stored in a refrigerator
for several weeks until needed. As noted
above, fresh whole blood can also be separated into its component parts. Whole blood contains everything: red blood
cells, serum proteins, clotting factors, and platelets. Because the most common reason for a
transfusion is severe anemia, packed red blood cells (pRBCs) may be a more
appropriate product. The advantage of
using pRBCs is that you are administering the same amount of red blood cells as
that found in a unit of whole blood, but it is in a much smaller volume, making
it safer for animals with concurrent heart or kidney disease.
Cats have specific blood types, similar to humans: Type A,Type B, and Type AB. Unlike humans,
there are no type O cats. The majority (99{9566c0a8c38d7ef68d82188668983429d8c3d2118cd02557d3ef814309ae7d10})
of cats in the United States are type A.
Type B is less common. In Europe,
Japan, and Australia, higher percentages of cats with Type B blood are
found. Some breeds of cats (for example:
British shorthair, Devon rex, Cornish rex, exotic shorthair, Abyssinian,
Japanese bobtail, Persian, Himalayan, Somali, and sphinx) have a higher
percentage of Type B blood. Although
purebred cats are most likely to be Type B compared to non-purebred, it is
interesting to note that Siamese cats are reported to be 100{9566c0a8c38d7ef68d82188668983429d8c3d2118cd02557d3ef814309ae7d10} Type A. Cats with blood Type AB are extremely
rare. In 29 years of veterinary practice,
and having performed countless blood typing procedures, I have still not
encountered a type AB cat.
 |
| The Rapid Vet H Blood Typing Test. Both cats here are Type A. |
Transfusing blood products into a cat isn’t a benign
procedure. The feline immune system can
react dramatically to blood components, with life-threatening
consequences. The serum of cats with Type
A blood possesses antibodies that react against Type B red blood cells. Conversely, the serum of cats with Type B
blood possesses antibodies against Type A red blood cells. In Type A cats, the amount of antibodies they
have against Type B blood is relatively low, so accidentally giving Type B
blood to a Type A cat will typically result in a mild reaction, with the
transfused Type B red blood cells undergoing attack and destruction by the
immune system of the recipient within 2 to 3 days. However, the amount of anti-A antibodies in
the blood of a Type B cat is very high, and administering even a small amount
of Type A blood into a Type B cat can cause acute, dramatic destruction of the
transfused red blood cells, resulting in a potentially fatal transfusion
reaction. It is therefore imperative
that blood typing be performed before any transfusion is undertaken. To be even safer, it is advisable to perform
an additional procedure called crossmatching to further minimize the risk of a transfusion
reaction. A detailed description of
crossmatching is beyond the scope of this article, but it involves mixing donor
red blood cells with serum of the recipient (major crossmatch) and mixing donor
serum with recipient red blood cells (minor crossmatch) and observing the
reaction.
procedure. The feline immune system can
react dramatically to blood components, with life-threatening
consequences. The serum of cats with Type
A blood possesses antibodies that react against Type B red blood cells. Conversely, the serum of cats with Type B
blood possesses antibodies against Type A red blood cells. In Type A cats, the amount of antibodies they
have against Type B blood is relatively low, so accidentally giving Type B
blood to a Type A cat will typically result in a mild reaction, with the
transfused Type B red blood cells undergoing attack and destruction by the
immune system of the recipient within 2 to 3 days. However, the amount of anti-A antibodies in
the blood of a Type B cat is very high, and administering even a small amount
of Type A blood into a Type B cat can cause acute, dramatic destruction of the
transfused red blood cells, resulting in a potentially fatal transfusion
reaction. It is therefore imperative
that blood typing be performed before any transfusion is undertaken. To be even safer, it is advisable to perform
an additional procedure called crossmatching to further minimize the risk of a transfusion
reaction. A detailed description of
crossmatching is beyond the scope of this article, but it involves mixing donor
red blood cells with serum of the recipient (major crossmatch) and mixing donor
serum with recipient red blood cells (minor crossmatch) and observing the
reaction.
Once the compatibility of the donor and the recipient has
been confirmed, the transfusion can be performed. Initially, the blood should be administered
slowly. If no adverse effects are
witnessed after 30 to 60 minutes, the rate of administration can be
increased. The rate depends on the
urgency of the cat’s condition. Cats
that are in shock from acute blood loss require rapid blood administration. Cats with cardiac disease are at risk of
fluid overload and congestive heart failure, and may require a much more
judicious rate of administration. A typical transfusion is completed in 4 to 6
hours. The goal of the transfusion, in
most cases, is to increase the patient’s PCV sufficiently to reverse the signs
of anemia. A reasonable aim is to
achieve a PCV of 20{9566c0a8c38d7ef68d82188668983429d8c3d2118cd02557d3ef814309ae7d10}, although this isn’t always possible.
been confirmed, the transfusion can be performed. Initially, the blood should be administered
slowly. If no adverse effects are
witnessed after 30 to 60 minutes, the rate of administration can be
increased. The rate depends on the
urgency of the cat’s condition. Cats
that are in shock from acute blood loss require rapid blood administration. Cats with cardiac disease are at risk of
fluid overload and congestive heart failure, and may require a much more
judicious rate of administration. A typical transfusion is completed in 4 to 6
hours. The goal of the transfusion, in
most cases, is to increase the patient’s PCV sufficiently to reverse the signs
of anemia. A reasonable aim is to
achieve a PCV of 20{9566c0a8c38d7ef68d82188668983429d8c3d2118cd02557d3ef814309ae7d10}, although this isn’t always possible.
 |
| My beloved Crispy |
[I have personal experience with blood transfusions not only
as a veterinarian, but as a cat owner. Two years ago, my 14 year-old cat Crispy
underwent surgery to remove an intestinal tumor. Immediately post-surgery, Crispy became
alarmingly pale and was very slow in waking from anesthesia. A quick in-house test revealed a dangerously
low red blood cell count (PCV of 12{9566c0a8c38d7ef68d82188668983429d8c3d2118cd02557d3ef814309ae7d10}) and a transfusion was going to be needed
if she was going to have any chance of recovery. Although 99{9566c0a8c38d7ef68d82188668983429d8c3d2118cd02557d3ef814309ae7d10} of domestic shorthaired cats in
the U.S. are Type-A, I quickly checked Crispy’s blood type right after surgery,
and to my shock and dismay, she was a very definite Type B. Frantic calls to the first two nearby
emergency clinics were futile; they only had Type A blood on hand. Miraculously, the third referral center had
two units of Type B packed red blood cells stored in their refrigerator. A harrowing 20-minute taxi ride ensued, with my
anesthetized cat on my lap, her endotracheal tube still in her windpipe. Thankfully, the emergency staff was ready and
waiting, and her transfusion began immediately upon arrival. She woke up from anesthesia a tense 40
minutes later. (Catnip subscribers may
remember this case, which I described in detail in the article “When Doctor
Becomes Client” in the July 2015 issue of Catnip). ]
as a veterinarian, but as a cat owner. Two years ago, my 14 year-old cat Crispy
underwent surgery to remove an intestinal tumor. Immediately post-surgery, Crispy became
alarmingly pale and was very slow in waking from anesthesia. A quick in-house test revealed a dangerously
low red blood cell count (PCV of 12{9566c0a8c38d7ef68d82188668983429d8c3d2118cd02557d3ef814309ae7d10}) and a transfusion was going to be needed
if she was going to have any chance of recovery. Although 99{9566c0a8c38d7ef68d82188668983429d8c3d2118cd02557d3ef814309ae7d10} of domestic shorthaired cats in
the U.S. are Type-A, I quickly checked Crispy’s blood type right after surgery,
and to my shock and dismay, she was a very definite Type B. Frantic calls to the first two nearby
emergency clinics were futile; they only had Type A blood on hand. Miraculously, the third referral center had
two units of Type B packed red blood cells stored in their refrigerator. A harrowing 20-minute taxi ride ensued, with my
anesthetized cat on my lap, her endotracheal tube still in her windpipe. Thankfully, the emergency staff was ready and
waiting, and her transfusion began immediately upon arrival. She woke up from anesthesia a tense 40
minutes later. (Catnip subscribers may
remember this case, which I described in detail in the article “When Doctor
Becomes Client” in the July 2015 issue of Catnip). ]
Although blood transfusions are infrequently performed in
general practice, the increased availability of feline blood and blood products
and the willingness of cat owners to pursue more advanced care for their pets
has made this often life-saving procedure more common. By transfusing a patient only with the blood
component that is needed, knowing the blood types of the donor and recipient,
and performing a crossmatch right before the transfusion, most transfusions can
be performed safely and effectively.
general practice, the increased availability of feline blood and blood products
and the willingness of cat owners to pursue more advanced care for their pets
has made this often life-saving procedure more common. By transfusing a patient only with the blood
component that is needed, knowing the blood types of the donor and recipient,
and performing a crossmatch right before the transfusion, most transfusions can
be performed safely and effectively.