What is a Blood Transfusion?

A blood transfusion refers to the transfer of one person’s blood to another person.
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When is a Blood Transfusion required?

A blood transfusion may be necessary when the patient has had severe blood loss or has a low haemoglobin level (red blood cell count). Such situations where a blood transfusion is required include:

• Patients who suffer from severe anaemia or are lacking certain components of the blood such as platelets or plasma.
• Patients who suffer from sickle cell anaemia or thalassaemia that affect the functions of the red blood cells usually need frequent blood transfusions.
• Blood transfusion may also be a part of the treatment for blood cancers, including leukaemia, especially when the patient is undergoing a stem cell transplant or receiving chemotherapy.
• Severe bleeding as a result of surgery, a severe accident, or childbirth will require a blood transfusion to replenish the blood loss.
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What are the different types of blood transfusions?

The type of blood transfusion a patient requires is determined by their condition and the specific components lacking in their blood. The three main types of transfusion are:

1. Red Cell Transfusion
2. Platelet Transfusion
3. Plasma Transfusion
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When are Red Cell Transfusions required?

• Significant anaemia resulting in breathlessness on slight exertion, chest pain due to angina, and extreme fatigue which affects the routine activities of the patient.
• Severe bleeding such as in road traffic accidents or bleeding from the gut.
• Surgical procedures resulting in high blood loss.
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When are Platelet Transfusions required?
Platelets are required for the blood to clot. When the platelet count is low, there is an increased risk of bleeding. Patients may need a platelet transfusion to prevent excessive blood loss.
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The common causes of low platelets include:

• Reduced production of platelets by the bone marrow due to leukaemia or the side effects of chemotherapy
• Viral infections such as dengue fever
• Destruction of platelets due to conditions such as sepsis, Immune Thrombocytopaenic Purpura (ITP) and Disseminated Intravascular Coagulation (DIC).
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When are Plasma Transfusions required?
Plasma transfusions are usually recommended for the replacement of clotting factors to stop or prevent a severe bleeding episode. Some inherited disorders that affect the production or function of clotting factors may also require a plasma transfusion.
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What are the common blood groups?

There are four common blood groups which are A, B, AB, and O, based on the ABO system of classification. The positive “+” or the negative “-” sign after the letters A, B, AB, or O indicates the presence or absence of the rhesus (RhD) antigen, respectively. It is important to check the blood groups of the recipient and donor before a blood transfusion to ensure blood group compatibility to prevent a condition called haemolysis which is when there is destruction of the red blood cells.
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What to expect when you have a Blood Transfusion

What happens before the blood transfusion?

• A sample of your blood is taken to check your blood group. 
• The cross-matching of the donor’s blood with the recipient’s blood is done to ensure compatibility. 
• Before a blood transfusion, you may be given a dose of paracetamol or an antihistamine to prevent a reaction.
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What happens during the blood transfusion?

• A cannula is inserted into a vein in your hand or arm.
• This cannula is connected to a bag of blood through a long tube, and the blood runs from the bag through the tube into your vein. 
• It usually takes 2 – 4 hours for the transfusion of 1 bag of blood.  If you are receiving a platelet transfusion, this usually takes around 30 minutes.
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During the transfusion, your temperature, heart rate, and blood pressure will be monitored regularly. The nurse will also watch for the signs of an allergic reaction like skin rashes.
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In most cases, patients do not feel any discomfort during a blood transfusion. Some patients develop a fever or chills. This can be managed by slowing down the transfusion or taking a dose of paracetamol.
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What happens after a blood transfusion?
The haematologist may recommend some blood tests to check your response to the transfusion and assess the improvement in the blood cell counts.
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You can go home immediately after the transfusion unless you have developed any signs of reaction or need more blood. Your arm may ache and show mild bruising for a few days.
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Do contact the doctor if you experience difficulty in breathing or chest pain within 24 hours after having a blood transfusion.
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Is having a Blood Transfusion safe?

A blood transfusion is generally safe. In some cases, patients may develop a few side effects, such as:

• Fever: A low-grade fever may occur during or within 6 to 8 hours of a blood transfusion. Patients can take a dose of paracetamol to reduce the temperature.
• Rashes: An itchy wheal may appear on the skin at the site of blood transfusion. It can be treated by using antihistamine drugs.
• In rare cases, patients may develop a severe reaction resulting in the following adverse effects:
  • Anaphylaxis: A severe allergic reaction may occur, resulting in difficulty in breathing and a sudden drop in blood pressure. If not treated immediately, it may lead to life-threatening complications.
  • Transfusion Related Acute Lung Injury (TRALI): This is a rare, life-threatening complication that may occur within 6 to 8 hours of a blood transfusion resulting in severe breathlessness.
  • Haemolysis: This occurs due to the destruction of red cells by antibodies following transfusion of a mildly incompatible blood.
  • Infections like HIV (Human Immunodeficiency Virus), HCV (Hepatitis C Virus), and HBV (Hepatitis B Virus) due to the transfusion of blood from an infected donor.  This is very rare nowadays due to the stringent checks by the local blood banks.
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What are the long-term side effects of repeated Blood Transfusions?

Some disorders such as myelodysplastic syndrome and thalassaemia major need frequent blood transfusions over several years. These patients may develop iron overload which may result in damage to the heart, liver, and other vital organs. Iron chelation therapy that involves the removal of excess iron from the body can help to minimise the risk of such iron toxicity.
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Can I avoid a Blood Transfusion?

As blood transfusions carry some risks, it is advisable to minimise transfusions where possible.
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Some patients with anaemia can be treated with iron or vitamin B12 supplements. Others may benefit from erythropoietin (a hormone which stimulates red cells production) injections. Patients who are at risk of bleeding may not require platelet or plasma infusions. Instead medication such as tranexamic acid may be used to reduced bleeding.

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Disclaimer:
The information on the Centre For Clinical Haematology website is intended for educational use.  It should not be considered or used as a substitute for medical advice, diagnosis or treatment from a qualified health professional.