Scientists shine light on risks of blood transfusions

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Blood stocks constantly need replenishing. Blood donors (particularly A+) will receive letters through the door every few months, reminding them that each donation counts.

However, there are concerns that unnecessary blood transfusions are causing deaths. A study in PLOS Medicine said, ‘there is uncertainty about the balance of risks and benefits,’ of blood transfusions. They found that the survival rate doubled for critical patients given blood transfusions but those with less critical injuries were five times more likely to die if given a blood transfusion. This is particularly problematic when blood transfusions are used to treat anaemia, which is not life threatening.

This apparent anomaly arises because blood transfusions bring with them a number of complications; they can spread infections or cause allergic reactions, kidney failure, lung inflammation and weakening of the immune system. There has been a general rise in deaths in hospitals, according to a NHS review in July, due in part to problems with funding for staff and simple care.

Blood transfusions are costly and prices are set to rise; an estimate by Advancis Surgical states that it is currently about £930 per transfusion, including costs for storage, staff wages and vital lab analysis. After testing, more than 15% of the donated blood must be discarded. Advancis Surgical promote technology which salvages and recycles residual blood lost during surgery to be transfused back into the patient. Using a patient’s own blood would cancel out health risks associated with donor blood. They estimate that it would also save the NHS about £700 per patient.

A significant percent of major operations include a blood transfusion. Heart surgery is particularly reliant on them, but transfusions are most often used for trauma, which includes injuries from traffic collisions, falls and blows. Worldwide, over five million people die from these each year. Trauma can cause haemorrhaging that is difficult to stop. Haemorrhaging accounts for 30%–40% of deaths by trauma. A steadily ageing population will increase the need for blood-stock for 5-10 years, as the elderly are more prone to serious damage from knocks and falls.

If pressure is applied quickly to wounds, the need for blood transfusions is lessened. Restoring circulation after blood loss and topping up blood with a solution of salt water and proteins are other options. Some painkillers like aspirin and clopidogrel prevent blood clotting, so can worsen haemorrhaging, particularly when combined. Switching to just aspirin would reduce this risk. Treating anaemia before surgery might help; anaemia is not routinely tested for, even though blood loss from surgery can sometimes cause or worsen it. Alternatively, an intravenous drip containing iron could better help tackle anaemia post-surgery.

There is no real substitute for blood. Scientists are looking into a liquid that can carry oxygen and replace blood, for at least a short time. Since it is mainly red blood cells that need replacing, growing them from stem cells may be an option for the future.

Adrian Williams

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