How long does a blood transfusion take?

The duration of a blood transfusion can vary depending on the amount of blood required, the patient’s previous illnesses and the preferences of the treating physician. A blood bag contains approximately 250 ml of fluid. At the beginning, a small amount – approx.

20 ml – is usually transfused quickly. Afterwards, the flow rate is lowered until the entire content has been absorbed into the blood. This takes about 45 minutes to 1 hour per unit.

Since two or more blood preserves are usually given, the blood transfusion itself takes about 2 hours. If the blood is to be given as an out-patient – i.e. the patient comes to the hospital or a doctor’s practice, receives the blood transfusion and then leaves again – approx. 4 hours must be planned for 500 ml of blood, including preparation and monitoring after the administration of the blood units. A blood transfusion can lead to a short-term deterioration in the general condition of people with cardiac insufficiency or other serious pre-existing conditions if it is given too quickly. The reason for this is the sudden addition of blood, which can put a strain on the cardiovascular system.

How much blood is transfused?

Blood transfusions are administered in the form of blood preserves. A blood reserve contains approx. 300 ml of erythrocyte concentrate. How many blood units are administered depends on the patient’s haemoglobin level and the level to which you want to increase it. It can be roughly said that one unit of blood can increase the hemoglobin level by about 1 to 1.5 g/dl.

What are the risks of a blood transfusion?

The risk of serious side effects and complications occurring during or after a blood transfusion is nowadays very low due to good control systems and a great deal of experience in the administration of blood products. The most common side effects include fever, allergic reactions, mix-ups of blood products and the resulting breakdown of blood cells, infection with bacteria or viruses, and the occurrence of lung fluid that can significantly worsen breathing. A slight fever develops in about 0.1% of patients and is usually harmless.

Allergic reactions to components of the donated blood are usually mild and occur in about 0.5% of cases. Mix-ups of blood preserves occur in about one in 40,000 blood transfusions in Germany. The result can be the so-called “haemolytic transfusion reaction” – the decomposition of red blood cells.

This can cause symptoms such as fever, shortness of breath and pain in the back and chest, and in rare cases even circulatory problems with bleeding and organ failure. The risk of viruses also entering the recipient’s blood through a transfusion is particularly relevant for hepatitis B, hepatitis C and HIV. However, strict controls mean that these viruses are transmitted in less than one in one million transfusions.

Doctors try to minimise the above-mentioned risks by frequent controls of the patient and to quickly notice and treat the occurrence of side effects. As a result, there are extremely few serious consequences after a transfusion. Complications occur very rarely during or after a blood transfusion.

The reason for this is that over the past decades, ever better control systems have been developed that make blood products very safe in advance. In this way, many complications that were common 30 years ago have been reduced to a minimum. Today, the most frequent and severe complication is the “hemolytic transfusion reaction”, which usually occurs after blood products have been mixed up.

After the transfusion of the wrong blood group, red blood cells in the patient die, leading to fever, shortness of breath, nausea and pain, and sometimes to organ failure and severe bleeding. If the symptoms are recognized in time, the disease can usually be well controlled. Very rarely, severe infections occur with high fever, drop in blood pressure and organ failure due to blood infected with bacteria.

Another serious complication is the so-called “acute pulmonary insufficiency”, in which fluid enters the lung tissue and can lead to respiratory distress. Due to legal guidelines and investigations, serious side effects and complications are rare in blood transfusions. The donor is not only tested for various risk factors, but the blood is also tested for various pathogens such as HIV, hepatitis B and syphilis.

In addition, the blood group is of course determined. Despite these precautions, side effects can occur. Slight complications that can occur despite suitable blood groups are nausea, fever and chills, which disappear after some time.

Serious side effects occur when the blood groups of donor and recipient are not compatible. There is a reaction of the recipient’s immune system to the foreign components of the blood, resulting in anaphylactic shock, cardiovascular complications and in some cases kidney failure. This situation is life-threatening and requires immediate treatment.

Another serious side effect can occur if the blood contains pathogens such as HIV or hepatitis B viruses, which then transmit the disease to the blood recipient. Due to tests for these pathogens, the chance of infection through blood transfusion in Germany is very low. Side effects and complications can occur not only directly after the administration of the foreign blood, but also some time after that there is a risk for the recipient.

On the one hand, it is possible that, despite examinations, pathogens are present in the blood which later lead to illness. This is a particular risk in less developed countries, where not all important tests are always carried out. Pathogens such as HIV or the hepatitis B virus can lead to serious diseases and can even be life-threatening.

Since there are strict regulations and laws for blood transfusion in Germany, this is a very rare complication in this country. Another late consequence is an increased susceptibility to infection. During a blood transfusion, foreign tissue is introduced into the body.

Even if the blood groups are compatible, the immune system initially regards it as foreign to the body, which is an additional burden and thus increases the risk of infection. In rare cases, a transfusion results in the formation of antibodies against components of the blood. A later transfusion may then lead to hypersensitivity reactions or reduced efficacy of the transfusion.

Blood donors are asked about possible risk factors that would increase the likelihood of the blood being infected with pathogens. In addition, the blood is tested for various pathogens, such as HIV or hepatitis B. Nevertheless, a possible infection cannot be completely ruled out.

The risk of becoming infected with HIV during a blood transfusion is very low and is estimated at 1:16. 000. 000.