As we start to provide more advanced healthcare to cats and dogs, blood transfusions are becoming increasingly common and increasingly complex. Blood transfusions in dogs and cats may be needed for many reasons and come in many forms.
This cat is receiving a lifesaving blood transfusion
Where does the blood for pet blood transfusions come from?
Wherever possible, cats and dogs should receive blood from a donor of the same species and blood type. This may be a healthy pet belonging to another member of the public or a practice pet that belongs to the veterinary clinic or one of its staff members. In many instances, blood is collected from a donor at the time it is needed from an animal that is nearby. This fresh blood donation is the only way to collect and administer cat blood currently in the UK.
Dog blood is also available from blood banks which centralise the collection of blood from pet dogs through larger facilities which are then able to separate blood into different components and prepare it for storage. This has several advantages as it means that the same volume of blood from one donor can potentially be used to treat several patients rather than just one and blood can be stored for long periods of time meaning it is ready when it is needed rather than having to find a donor in an emergency.
If you have a healthy pet that you would like to become a blood donor, speak to your local veterinary clinic.
Why is blood given?
Blood contains many different components that can be beneficial or even lifesaving to sick animals.
When most people think of blood, they think of the red blood cells within it that give it its colour. Red blood cells are generally administered for the treatment of anaemia. Anaemia may occur due to bleeding, such as trauma or surgery, but may also be present due to cancer, kidney disease, some infections or auto-immune problems.
Blood collected from a single donation can be processed into several different products, including packed red blood cells (shown in the image on the left) and fresh frozen plasma (shown in the image on the right), allowing it to benefit more than one patient
Another type of cell found in blood are called platelets. Platelets are vital for blood clotting and so blood may be given to animals with low or defective platelets to stop them bleeding. Unfortunately, platelets cannot readily be stored from cats and dogs and so if blood is needed for platelets this usually needs to be fresh blood, taken from a donor and given straight away.
As well as the cells found in blood, the liquid component, plasma, is also very useful. Plasma contains many different proteins but the principal proteins of use in the treatment of cats and dogs are clotting factors, involved in the formation of blood clots. If a defect or deficiency in clotting factors is present then plasma can be given to replace the missing protein. Plasma can be further separated into a variety of products to get even more use out of a single donation if a specific protein is known to be missing or defective.
Is there any risk from a blood transfusion?
Cats and dogs may require transfusions for many different reasons but they can be lifesaving when they are required
Blood transfusions can be lifesaving but they are not without a small degree of risk.
Giving blood from one animal to another carries the risk of transmitting infections. Blood donors are usually screened to minimise such risk and diseases that can be transmitted by such methods are uncommon in cats and dogs in the UK.
Giving blood from another animal or blood that has been stored for any length of time can also stimulate problems in the immune system. Such reactions are uncommon but problems such as mild fevers or episodes of nausea do occur from time to time during or after a transfusion.
In certain circumstances transfusions can be fatal. This is usually due to a type of reaction called an acute haemolytic transfusion reaction. These reactions are preventable by blood typing animals before they receive blood and crossmatching them if appropriate. These reactions are more likely if an animal has had another blood transfusion in the past and so it is important to tell your vet if this is the case.