Focus on: Blood transfusions
Blood transfusions can be life-saving, but what really happens? Senior Cardiac Nurse Emily McGrath hears from Professor Gavin Murphy about why you would need a blood transfusion and what the blood transfusion benefits are.
Why would you have a blood transfusion?
There are two main reasons you would have a blood transfusion. One is if you have a low level of haemoglobin (the protein in your blood that carries oxygen throughout your body).
A low level is called anaemia and can put a strain on your heart, particularly if you are going to have a cardiac procedure such as bypass surgery.
The other reason is if you have bled a lot, perhaps because of surgery or having had a device inserted, or if you have internal bleeding, which can sometimes happen as a result of medications such as aspirin, warfarin or other anticoagulants.
What types of blood transfusion might you have?
We don’t give people ‘whole blood’ any more. Blood is taken to one of five national processing centres after testing and is split into blood components.
Every unit that is donated is separated into red blood cells, plasma and platelets, and white blood cells. Red cells are transfused for the reversal of anaemia or in severe bleeding, platelets and plasma are given to help stop bleeding caused by drugs or surgery, and white blood cells are used (less often) to treat some blood disorders.
When might you need a blood transfusion?
This is not always clear-cut and the British Heart Foundation has been funding research to help us increase knowledge in this area.
A normal level [of haemoglobin] is 120 to 175 grams per litre, depending on your gender and other considerations.
When you’re anaemic, it is difficult to know when exactly you need a transfusion. Some people set a haemoglobin threshold that they use to guide treatment. Low levels of haemoglobin are quite well tolerated by most people, even when it is as low as 70 to 80 grams per litre (g/l).
A normal level is 120 to 175g/l, depending on your gender and other considerations. However, your heart’s ability to cope can be influenced by factors including whether you have heart failure or angina and whether you are bleeding.
If your transfusion is to treat bleeding, you would need one if your blood pressure is low or if you are clinically unstable.
What are the benefits of a blood transfusion?
In the case of severe bleeding, the benefits are life-saving. If you have anaemia, we know very low haemoglobin puts additional strain on your heart, which is more dangerous when you have heart disease.
There is no benefit of transfusion if your haemoglobin levels are above 70 to 80g/l.
What are the risks of a blood transfusion?
It is almost impossible to acquire an infection from a blood transfusion because each donation is thoroughly tested.
The main risk is that you get blood intended for someone else – in other words, the wrong blood. That is the most common cause of death following transfusion, but is extremely rare (around five cases a year in the UK).
You can have very rare transfusion reactions, including a rash or feeling breathless and unwell, but this is usually recognised before the transfusion has finished and has no long-term effects.
In extremely rare cases (about one in 10,000 transfusions), you can have a life-threatening complication, where transfusion damages the lungs and causes multi-organ failure.
Does having a blood transfusion mean you can’t be a blood donor?
NHS Blood and Transplant currently doesn’t accept blood donations from those who have had a transfusion since 1980. If you have received blood and would like to give back, you could suggest to family and friends that they become blood donors.
What is the latest research in this area?
The British Heart Foundation has funded more than 10 years of research into how we can make blood transfusion safer, particularly for heart surgery patients.
We have also evaluated different drugs that stop people bleeding after surgery, so we know more about which are most effective.
BHF researchers led the largest ever UK trial looking at what haemoglobin threshold was safe in cardiac surgery patients. The same researchers in Leicester and Bristol have run a study to see if measurements of oxygen levels in the brain can give more precise and personalised information about whether a transfusion is needed.
We have also evaluated different drugs that stop people bleeding after surgery, so we know more about which are most effective. We have looked at tests of platelet function and blood clotting to see whether they can be used to guide plasma and platelet transfusions in bleeding patients.
Now, BHF researchers in Leicester are leading an exciting trial of a new type of red blood cell for transfusion that may deliver oxygen more efficiently to the cells in the body.
In this trial, stored blood from blood banks is treated with a rejuvenating solution before it is transfused to patients in one of seven UK cardiac surgery centres.
Meet the expert
Professor Gavin Murphy is an Academic Cardiac Surgeon at the University of Leicester. He has been the British Heart Foundation Chair of Cardiac Surgery at the University of Leicester since 2012.
His research includes diseases affecting the thoracic aorta, blood management and the prevention of organ damage resulting from surgery.
- Interested in donating blood and helping save a life? Find out more about giving blood.