health care worker with blood products

Use of blood products

In the era before blood transfusions, many mothers died during childbirth because of excessive bleeding during or after birth. Today, blood transfusions are readily available and safe to use. The chance of needing a blood transfusion during childbirth is very small. In this hospital, it is less than 1 in 500 births. Contrary to popular belief, the chance of needing a transfusion is not much higher when having a c-section.

Learn more about blood transfusion on the Ontario Regional Blood Coordinating Network's website.

Transfusions

Blood products are used to replace low levels of different elements of the blood because of loss due to bleeding or because of failure of the blood forming tissues. The main components of blood that may be transfused are:

Component Function
Red blood cells Carry essential oxygen which tissues and organs need to survive. 
Platelets Small structures that help prevent or stop bleeding. No effective substitute exists. Patients who have low platelet levels or whose platelets do not function properly may need a platelet transfusion. 
Plasma

Contains many substances, such as proteins, and is mainly used to treat a lack of factors that promote coagulation (blood clotting). 

Other blood products There are some other blood components/factors which are required only in special circumstances. Your doctor will discuss these with you if there is a likelihood that you will need them. 

Why might I need a transfusion?

  • Your blood loss due to surgery, trauma, or bleeding etc. is greater than 20% of your blood volume (more than about 1 litre)
  • You are severely anemic (have very low haemoglobin)
  • Your platelets or coagulation factors are lor or not functioning properly

Risks and benefits of a blood transfusion

A blood transfusion is a medical procedure prescribed by a doctor. Blood donations are separated into several components which may be given separately or together to treat various medical and surgical conditions. After evaluating your condition, your doctor may consider that a transfusion is necessary as part of your overall treatment. The doctor will then discuss with you the risks and benefits of receiving blood products and then get your written consent.

What are the risks of transfusion? (see chart below)

Allergic reactions: These are not uncommon and may cause hives, which are usually mild and easily treated. You should tell your caregiver if you have had such reactions to transfusions in the past.

Fever reactions: These are also not uncommon in patients who have been previously transfused or pregnant. These are generally not severe and are easily treated. Patients who have had severe fever reactions with transfusions may be treated for this before the transfusion. You should tell your caregiver if you have had such reactions to transfusions in the past.

Hemolytic reactions: These are rare and occur most commonly when the patient's blood antibodies destroy the donor red blood cells. These reactions may sometimes be severe and result in bleeding and in kidney failure. Hemolytic reactions are usually prevented by careful blood testing, blood preparation and administration with attention to patient identification procedures so that the correct blood is given to the correct patient. You should tell your caregiver and the nurse if you are known to have any blood group antibodies.

Transmissible infections: All volunteer donor blood has been screened for infectious diseases. In addition, donors are asked about possible exposure to transmissible infectious diseases. Specific tests are performed on the blood for hepatitis, HIV (AIDS) and other infectious agents and only blood that tests negative is released for use. The risk of chronic infection or death from transfusion-transmitted infection is very small, but the risk cannot be completely removed by available testing. 

Some of the infectious diseases may have little adverse effects, others may have serious consequences.

Non-infectious complications Estimated risk of event Dying from lung cancer after smoking a pack a day for 30 years = 1 in 10
Minor allergic reactions (hives or rash) 1 in 100 Risk or death associated with hip replacement surgery = 1 in 100
Fluid overload 1 in 100  
Fever or chills 1 in 300  
Lung injury 1 in 12,000 Annual risk of death in a motor vehicle crash = 1 in 10,000
Incompatible blood reaction 1 in 40,000  
Serious allergic reaction 1 in 40,000 Annual risk of being murdered in Canada = 1 in 60,000

 

Infectious complications Estimated risk of event Death from anesthesia in a fit patient = 1 in 200,000
Bacteria 1 in 10,000 platelet pools

1 in 250,000 red blood cells
 
West Nile Virus Less than 1 in 1 million Annual risk of death from accidental electrocution in Canada = 1 in 1 million
Hepatitis B 1 in 1.7 million  
Human T Lymphotrophic Virus (HTLV) 1 in 2.5 million  
Chagas disease 1 in 4 million  
Hepatitis C 1 in 6.7 million Annual risk of death from bein gstruck by lightening in Canada = 1 in 5 million
Human Immunodeficiency Virus (HIV) 1 in 8 million  
In canada, donors are never paid for their blood and Canada's blood supply is considered one of the safest in the world.

What are the risks of not having a transfusion?

When you have lost so many red blood cells that your body is not getting enough oxygen, there is a risk of damage to vital organs such as the brain, heart and kidneys. Transfusion may be necessary to prevent such damage. The point at which transfusion is necessary varies with different patients and in different circumstances. Your physician, surgeon or anaesthetist will evaluate and recommend when a transfusion is needed based on your individual case.

Where does donor blood come from?

Blood has many complex functions, most of which can not be replicated by an artificial substitute. In Canada, blood is collected from volunteer donors by the Canadian Blood Services.

The blood collection centre carefully screens all prospective donors to protect both the person who donates the blood and the patient who receives it. Before every donation, questions must be answered about the donor's health. These questions are designed to identify and eliminate prospective donors who may have a greater risk of transmitting infectious diseases. 

Blood is collected using sterile disposable needles attached to the collection bag. Every donation is tested for infections that might be transmitted by blood transfusion. Any donated blood that does not pass the testing procedures is destroyed. Even though new tests are constantly being researched, there is still a small risk of disease transmission. It should be recognized that this risk is generally much smaller than the risk associated with most surgical procedures themselves.

Before blood is issued for transfusion, it is tested for:

  • Infectious diseases
  • Syphilis
  • Hepatitis B and C
  • HTLV-2 (potential leukemia virus)
  • HIV 1 and 2 (the AIDS virus)
  • West Nile virus
  • Blood group and compatibility

Before transfusion, the hospital tests the donated units along with the patient's blood to reduce the risk of incompatibility. However, the blood cannot routinely be tested to detect allergy causing substances.

Can I donate directly to my family member?

Directed blood donations are units donated for a specific recipient. Currently in Canada (other than in Quebec), directed blood donations are only from the following recipients:

  • Parent to minor child

  • Patients with rare blood cell type

  • Neonatal alloimmune thrombocytopenia

  • HLA-alloimmunized thrombocytopenic patients requiring platelet transfusions

Possible alternatives to red cell transfusion

Your doctor may discuss some possible alternatives to transfusion. Sometimes a blood alternative such as saline or Pentaspan can be given to you instead of red cells. However, these may not be good enough. Some patients may be suitable for treatment with blood enhancing medications such as iron and erythropoietin. There is constant ongoing research into artificial substitutes for blood components and these may currently be available in limited specific research studies.

Benefits are carefully weighed against the risks before any blood products are used. It is important to remember that appropriately used, blood products can be life-saving.

It is important to note that with ongoing research, better tests are being constantly developed, resulting in lower risks from transfusions.

Make sure you let your doctor know if you have religious reasons why you cannot take blood (e.g. Jehovah's Witness).

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