A blood transfusion is a routine medical procedure in which donated blood is provided to you through a narrow tube placed within a vein in your arm. It is a way of adding blood to your body after an illness or injury. If your body is missing one or more of the components that make up healthy blood, a transfusion can help supply what your body is missing. Depending on how much blood you need, a transfusion can take between 1 and 4 hours.
A blood transfusion is given through tubing connected to a needle or fine tube (catheter) that’s in a vein. The amount and part of the blood transfused depends on what the patient needs. First, blood tests such as a complete blood count (CBC) are done to find out if the patient’s symptoms are likely to be helped by a transfusion. A CBC measures the levels of components within the blood such as red blood cells, white blood cells, platelets and whether your blood is Rh-positive or Rh-negative. Tests of clotting (coagulation) may also be done if abnormal bleeding is a problem.
If a transfusion is needed, it must be prescribed by a health care provider. At that point, more blood tests must be done to find a donated blood component that closely matches the patient.
Why Would You Need a Blood Transfusion?
People receive blood transfusions for many reasons:
- You’ve had major surgery or a serious injury and you need to replace lost blood
- You’ve experienced bleeding in your digestive tract from an ulcer or other condition
- You have an illness like leukaemia or kidney disease that causes anaemia (not enough healthy red blood cells)
- You’ve received cancer treatments like radiation or chemotherapy
- You have a blood disorder or severe liver problems
Blood has several components, including:
- Red cells carry oxygen and help remove waste products
- White cells help your body fight infections
- Plasma is the liquid part of your blood
- Platelets help your blood clot properly
A transfusion provides the part or parts of blood you need, with red blood cells being the most commonly transfused. You can also receive whole blood, which contains all the parts, but whole blood transfusions aren’t common.
Researchers are working on developing artificial blood. So far, no good replacement for human blood is available.
Types of blood:
When you get a transfusion, the blood you’re given has to work with the type of blood you have. If you get a transfusion that does not work with your blood type, your body’s immune system could fight the donated blood. This can cause a serious or even life-threatening transfusion reaction. To be sure no mistakes are made, donated blood is carefully tested to find out what type it is. This is done when it’s taken from the donor and again once it’s received by the hospital lab. The blood bag is labelled with the type of blood it contains. When a person needs a blood transfusion, a blood sample is drawn from them and tested the same way.
All blood has the same components, but not all blood is the same. People have different blood types, which are based on substances called antigens on a person’s blood cells. The 2 most important antigens in blood typing are called A, B, O, and Rh.
- Each person has an ABO blood type – either A, B, AB, or O – which means antigen A, antigen B, both antigens (type AB), or neither antigen (type O) is found on their blood cells.
- Each person also is either Rh-positive or Rh-negative (you either have Rh or you don’t).
Blood is either Rh-positive or Rh-negative, depending on whether the red blood cells have Rh antigens on their surface. A person who has type B, Rh-positive blood is called B positive, whereas a person with type B, Rh-negative blood is B negative. If you have Rh-positive blood, you can get Rh-positive or Rh-negative red blood cell transfusions. But people with Rh-negative blood should only get Rh-negative red blood cells except in extreme emergencies. This is because an Rh-positive blood transfusion can cause a person with Rh-negative blood to make antibodies against the Rh factor, causing a transfusion reaction.
The transfusion process:
Most blood transfusions are given in the hospital or in clinics. Red blood cell transfusions are usually started slowly while the patient is watched closely for the signs and symptoms of a transfusion reaction. The patient’s vital signs (such as temperature, heart rate, and blood pressure) are checked often. If there are no problems, the infusion rate will slowly be increased (so the blood goes in faster). Each unit of red blood cells is usually given over a couple of hours and should be completed within 4 hours. Other blood products, like plasma and platelets, go in much faster. A visiting nurse can give transfusions and monitor patients in their homes. Home transfusions follow the same safety standards as hospital transfusions. A health care provider must be sure that a patient’s health is stable for transfusion at home. Emergency medical care must be available close by in case it is needed. And the blood must be kept within a certain temperature range while being taken to the home.
Risks in blood transfusions:
Infections were once the main risk, but they have become extremely rare with testing and donor screening. Transfusion reactions and other non-infectious problems are now more common than infections.
1. Transfusion reactions- Blood transfusions sometimes cause transfusion reactions. There are several types of reactions and some are worse than others. Some reactions happen as soon as the transfusion starts, while others take several days or even longer to develop.
To avoid such conditions, the blood type of the unit is checked many times, and the unit is carefully matched to be sure that it matches the blood type and Rh factor of the person who will get it. After that, both a nurse and blood bank lab technician look at the information about the patient and the information on the unit of blood (or blood component) before it’s released. The information is double-checked once more in the patient’s presence before the transfusion is started.
2. Allergic reaction- This is the most common reaction. It happens during the transfusion when the body reacts to plasma proteins or other substances in the donated blood. Usually, the only symptoms are hives and itching, which can be treated with antihistamines like diphenhydramine (Benadryl).
3. Febrile reaction- The person gets a sudden fever during or within 24 hours of the transfusion. Headache, nausea, chills, or a general feeling of discomfort may come with the fever. Acetaminophen (Tylenol) may help these symptoms. These reactions are often the body’s response to white blood cells in the donated blood. They are more common in people who have had transfusions before and in women who have been pregnant several times.
Patients who have had febrile reactions or who are at risk for them are usually given blood products that are leukoreduced. This means that the white blood cells have been removed by filters or other means. People with cancer often get leukoreduced blood products.
4. Transfusion-related acute lung injury- Transfusion-related acute lung injury (TRALI) is a rare but very serious transfusion reaction. It can happen with any type of transfusion but is much more likely in people who are already seriously ill. It often starts within 1 to 2 hours of starting the transfusion but can happen anytime up to 6 hours after a transfusion. There’s also a delayed TRALI syndrome, which can begin up to 72 hours after the transfusion is given. The main symptom of TRALI is trouble breathing, which can become life-threatening. If TRALI is suspected during a transfusion, the transfusion should be stopped right away. Most of the time, TRALI goes away within 2 or 3 days if the person is helped with oxygen, fluids, and sometimes a breathing machine. Researchers are working on other ways to reduce the risk of TRALI.
5. Acute immune hemolytic reaction- An acute hemolytic reaction is the most serious type of transfusion reaction. It happens when the donor and patient blood types do not match. The patient’s antibodies attack the transfused red blood cells, causing them to break open (hemolyze) and release harmful substances into the bloodstream. Patients may have chills, fever, chest and lower back pain, and nausea. The kidneys may be badly damaged, and dialysis may be needed. A hemolytic reaction can be deadly if the transfusion is not stopped as soon as the reaction starts.
6. Infections: Blood transfusions can transmit infections caused by bacteria, viruses, and parasites. Testing units of blood for infection and asking questions to learn about donor risks has made the blood supply very safe. Still, no test or set of questions is 100% accurate. blood gets contaminated with tiny amounts of skin bacteria during donation.