Blood transfusion

What is a blood transfusion?

A blood transfusion is the transfer of blood or blood components from a donor dog to a recipient dog. The aim is to improve the recipient's blood volume, oxygen transport and clotting ability. There are different types of blood transfusion, depending on which blood components are transferred:

• Whole blood transfusion: all of the donor's blood is transfused, including red blood cells, white blood cells, platelets and plasma. This type of transfusion is used if the recipient suffers from a lack of red blood cells (anemia) as well as a lack of other blood cells or coagulation factors.
• Red blood cell transfusion: Only the donor's red blood cells are transfused. This type of transfusion is used when the recipient suffers mainly from anemia caused by severe blood loss or destruction of their own red blood cells.
• Plasma or serum transfusion: Only the plasma or serum of the donor is transfused. Plasma is the liquid part of the blood that contains water, proteins, electrolytes and coagulation factors. The serum is the plasma without the coagulation factors. This type of transfusion is used when the recipient suffers from a lack of coagulation factors or proteins caused by liver disease, poisoning or infection.
• Platelet transfusion: Only the platelets of the donor are transfused. Platelets are responsible for blood clotting and prevent bleeding in the event of injury. This type of transfusion is used if the recipient suffers from a platelet deficiency caused by an immune reaction, an infection or a drug side effect.

When is a blood transfusion necessary?

A blood transfusion may be necessary in various situations, for example

• In the case of acute or chronic blood loss due to trauma, surgery, tumor hemorrhage or parasite infestation.
• In the case of anemia caused by destruction of the patient's own red blood cells (haemolytic anemia), which can be caused by an immune reaction, an infection or a drug side effect.
• Anemia caused by reduced production of the patient's own red blood cells (aplastic anemia), which can be caused by bone marrow disease, chemotherapy or radiotherapy.
• In the case of a coagulation disorder due to a lack of coagulation factors or platelets, which can be caused by liver disease, poisoning, an infection or a drug side effect.

The decision for a blood transfusion depends on various factors, such as the severity of the disease, the general condition of the dog and the availability of suitable donor blood. The vet will carry out various tests before a transfusion to determine the need and compatibility.

How is a blood transfusion carried out?

A blood transfusion is usually carried out under inpatient conditions in a veterinary clinic. The donor dog must be healthy and free of infectious diseases that can be transmitted via the blood, such as leishmaniasis, babesiosis or ehrlichiosis. The donor dog must also have a matching blood group that is compatible with that of the recipient dog. There are eight different blood groups in dogs, which are designated by the letters DEA (Dog Erythrocyte Antigen). The most common blood groups are DEA 1.1, DEA 1.2 and DEA 4. The DEA 1.1 blood group is the most important, as it can trigger the strongest immune reactions. A dog with the blood group DEA 1.1 can only receive blood from another dog with the same blood group, while a dog without this blood group (DEA 1.1 negative) can receive blood from both a DEA 1.1 positive and a DEA 1.1 negative dog.

The donor dog is sedated before the transfusion and connected to a venous catheter through which the blood is taken. The blood is collected in special bags filled with an anticoagulant solution to prevent clotting. The blood can be used either fresh or cooled, depending on which blood components are required. Refrigerated blood can be stored for up to six weeks, but loses its effectiveness over time.

The recipient dog is also connected to a venous catheter through which the donor blood is slowly infused. The speed of transfusion depends on the size of the dog and the condition of the circulatory system. The transfusion can take between half an hour and several hours. During the transfusion, the recipient dog is closely monitored in order to detect and treat any complications at an early stage.

What are the risks of a blood transfusion?

A blood transfusion is a safe and effective procedure that can save the lives of many dogs. However, there are also some risks that need to be considered:

• An immunological reaction: this involves a defensive reaction of the recipient's immune system against the donor blood, which can lead to destruction of the transfused blood cells or damage to the dog's own organs. Symptoms may include fever, chills, vomiting, diarrhea, shortness of breath or shock. This reaction can be acute or delayed and is usually due to an incompatibility of the blood groups. To avoid this, careful blood grouping and cross-matching must be carried out before each transfusion.
• An infectious reaction: This involves the transfer of pathogens from the donor to the recipient, which can lead to an infection. Symptoms may include fever, lethargy, loss of appetite or signs of the infectious disease in question. Depending on the incubation period of the pathogens, this reaction can occur immediately or only after days or weeks and is usually due to inadequate examination or testing of the donor blood. To avoid this, a comprehensive screening of the donor dog for infectious diseases must be carried out before each transfusion.
• A volumetric reaction: This is an overload of the circulatory system due to a too fast or too large amount of donor blood, which can lead to heart failure or pulmonary edema. Symptoms may include coughing, shortness of breath, cyanosis or palpitations. This reaction can occur during or shortly after the transfusion and is usually due to incorrect calculation or monitoring of the transfusion volume or speed.