In a nutshell, yes!
Just as with human medicine, small animal vets offer high standards of intensive medical care for their canine and feline patients. In certain situations, a blood transfusion can be a lifesaving procedure for an acutely or critically ill animal.
Why transfuse?
There may be various situations when a pet might need a transfusion, depending on the underlying cause or disease process. A common scenario would be haemorrhage (blood loss). For example externally and obviously through a road traffic accident. Or internally (and usually less obviously), with either a tumour that is bleeding into a body cavity, or potentially rodenticide (warfarin-rat poison) toxicity.
Other causes of anaemia which may necessitate a blood transfusion, include immune mediated haemolytic anaemia (where the body’s own immune system inappropriately attacks and destroys its own red blood cells), or a bone marrow disease, where there is inadequate production and replenishment of red blood cells.
How often do dogs and cats need a transfusion?
In haemorrhagic or haemolytic diseases the bone marrow typically remains healthy and within 3-5 days. Tthe body starts to show signs of new and increased red blood cell production itself (regenerative anaemias). With these conditions, a blood transfusion(s) would help stabilise the patient by improving the oxygen carrying capacity, until an adequate level of spontaneous regeneration has occurred. Additionally, with haemolytic diseases, a blood transfusion may “buy some time” until other medications can start to effectively control the underlying disease and stop the red cell destruction.
In contrast, with the majority of bone marrow disease, adequate regeneration by the patient may never occur (the anaemia is therefore described as non-regenerative). In such cases, sadly, a blood transfusion would only be expected to offer a palliative, supportive and short-term benefit.
What does blood do?
Blood is vitally important in maintaining a “balance” within the body (homeostasis) and has a number of functions. Chiefly, it carries oxygen and nutrients around the body and lungs for tissue metabolism, whilst also removing carbon dioxide and waste products. Alongside this, it carries cells of the immune system which fight infection and transports hormones.
What are the signs of anaemia?
A lack of adequate circulating blood volume, red cells or haemoglobin is called anaemia. This results in symptoms that include weakness, lethargy, pallor (pale mucous membranes), and increased heart and respiratory rates. Additionally, your vet may pick up a heart murmur, fever, jaundice and enlargement of the liver and or spleen. Pica (eating of substances of no nutritional value such as dirt or cat litter), is not infrequently seen in cats with anaemia and can be a relevant part of the history.
What dictates when a blood transfusion is needed?
The need for a blood transfusion will depend upon numerous factors. It, of course, varies on a case by case basis. Your vet would discuss these with you, as an owner of an anaemic pet.
Importantly this will include the speed at which the anaemia has developed. If very rapid, the body will have had an inadequate amount of time to respond and compensate and the animal is bound to be struggling.
Furthermore, the severity of the anaemia is a factor; clearly the more anaemic an animal is, the more severe the associated clinical signs.
Cats differ from dogs though. Given their relatively short red blood cell lifespan (70 days in cats compared to 120 days in dogs) and relatively small blood volume. They are unfortunately more prone to developing anaemia. Like many of the diseases we see in cats however, the anaemia may have actually been developing over a number of weeks and is tolerated well initially due to cat’s activity levels and haemoglobin structural alterations. Symptoms may appear suddenly and dramatically when they hit a “crisis” point or level however.
Do animals have blood types like humans?
Blood types do exist in dogs and cats albeit with some differences to humans. It is known that the presence of certain proteins or sugars on the red blood cell membrane determine the exact blood group of any animal and that these differ between individuals.
In dogs the DEA (dog erythrocyte antigen) system documents more than 12 different blood types. The DEA 1.1 group (positive or negative) is the most important (and only usually screened for) type. A universal donor dog would have blood type DEA 1.1 negative. Such dogs can safely donate blood to any other dog on a first occasion. Virtually no risk exists in this situation since dogs do not possess naturally occurring antibodies (against other blood group types). Such antibodies do however form a few days after a first transfusion, so second and subsequent donations must be both typed and cross-matched.
The complete opposite is true in cats. Their blood group system is the AB system and cats DO possess naturally occurring, strong antibodies against other blood group types. Both the donor and recipient cat must therefore be typed ahead of any planned transfusion, otherwise fatal reactions may occur.
In both cats and dogs, certain breeds are prone to belong to particular blood group types. For example, greyhounds are often DEA 1.1 negative and most domestic short hair cats in the UK would be blood type A.
From where is blood sourced?
In my 24hour emergency practice, we maintain a small, carefully selected list of dogs who have been previously blood typed. They are available voluntarily, at short notice to help donate whole blood. Typically however, and where specialist blood components are required, the Pet Blood Bank (PBB) Charity provides a canine blood bank service for vets across the UK. Blood is provided by owners volunteering their dogs at regular sessions, held frequently across the country. Following donation, blood is processed aseptically (cleanly). It is split into various products that include packed red cells, fresh frozen plasma and cryoprecipitate. All of which offer particular advantages due to their component parts and may be required in differing clinical situations. Products are stored until required by a veterinary practice, to whom they are promptly delivered by courier. Donor dogs must fulfil a variety of criteria to be eligible for donation. They can usually safely donate up to 4-6 times a year.
Cats represent a trickier situation given they can transmit blood bourne parasites and diseases (such as feline leukaemia virus FeLV and feline immunodeficiency virus FIV). Also, they are required to be sedated to donate blood safely. Replacing the volume of blood donated with saline intravenous fluids is also essential; the whole process is thus a more invasive procedure than with dogs. As a cat owning vet, sometimes my own cats have been volunteered as donors if their blood type is suitable! Equally, if an owner has a sibling cat at home, then this may be another option. Availability of cat blood will also hopefully increase in the future as similar schemes to the PBB are launched.
Discussion
I agree with you
Fascinating article, thank you for explaining it all so clearly. As an owner of both dogs and cats, I never knew there was such a difference between them from a blood point of view.