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The risks of blood transfusions

Blood bag
One in five transfusions may be 'inappropriate'

Ever since World War Two, blood transfusion has been saving the lives of people who are bleeding to death but some doctors are beginning to ask, whether the risks of transfusion in some non-emergency cases might outweigh the benefits.

Lesley Curwen lifts the lid on the scientific debate that has been raging in medical circles.

Millions of pounds are spent on making sure that people do not receive contaminated blood. Yet comparatively little has been spent on trying to

establish the benefits of giving some patients red blood cells.

In fact, it is a treatment that has never been tested anywhere in the world, for safety and efficacy, as a new drug would be.

As Professor of Critical Care, Tim Walsh in Edinburgh, explained: "I think it's remarkable that given blood transfusion has been almost a standard part of treatment of patients since the Second World War, we've managed to accrue so little evidence about who really needs it, particularly as blood transfusions go to patients where the risk benefit profile is uncertain.

"There's a general belief that blood at worst should do no harm and at best do good and that is one of the issues we now worry about that maybe receiving someone else's blood that has been stored could possibly do some harm."

There is a consensus among doctors that giving donated blood to people who bleed severely is vital in saving their lives or is essential for treating people who have conditions such as leukaemia.

Not all blood is not given to patients in those two broad categories.

Some estimates suggest they account for only about a third of red blood cell while others say it is two thirds.

The rest goes to patients undergoing surgery, or those suffering from a range of illnesses.

All of them have a low blood count, a below normal level of the protein haemoglobin, which carries life-giving oxygen around the body.

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The chief aim of giving someone red blood cells is to boost the amount of oxygen getting to their organs.

The obvious risks are a patient getting the wrong blood or contaminated blood.

However number of studies using patient records, suggest that giving blood to a patient may carry unexpected risks.

Heart surgeon Gavin Murphy, and his colleagues from Bristol Royal Infirmary analysed the records of more than 8,000 cardiac patients over a number of years, to try assess whether those who were given blood fared differently from those who were not.

The results of study, funded by the British Heart Foundation and published in the journal 'Circulation', questioned the efficacy of transfusing red cells.

The difficulty is finding any evidence that blood transfusions show benefits apart from bleeding
Dr Gavin Murphy, University of Bristol

Dr Murphy, said the study found a threefold increase in heart attacks, strokes and renal failure despite expectations that transfusions would help deliver more oxygen to tissues.

"That seems to show that blood transfusion is harmful."

But medical opinion is divided about this and other retrospective studies because they look back at patient data-bases rather than studying new patients in a randomised controlled trial - the gold-standard model of research.

'No benefits'

Dr Williamson told File On 4: "The problem with studies that look backwards is that comparing patients who have received younger blood or older blood, you can never be sure that the two groups are comparable.

Dr Murphy conceded his study cannot prove the red blood cell transfusions caused more infections and heart attacks, but said there was plenty of evidence showing that transfusions can cause harm.

"The difficulty is finding any evidence that blood transfusions show benefits apart from bleeding."

Some doctors are taking steps to reduce the number of transfusions, using new drugs to control bleeding and techniques such as recycling patients' own blood on the operating table.

Almost a decade ago the Department of Health launched a national drive to reduce blood use, called 'Better Blood Transfusion' which saw a 15% drop over the last five years of the amount of red blood cell transfusion in England and North Wales.

However Professor Mike Murphy, Haematologist at the John Radcliffe hospital, Oxford, who works closely with hospitals as well as NHS Blood and Transplant estimated that 400,000 red blood cell transfusions could be inappropriate and even put patients at risk.

'Unnecessary risk'

"There are about 2,000,000 red cell transfusions a year," he said.

"As many as 20% could be inappropriate....a lot of patients are being put at risk, the unnecessary risk of having a blood transfusion without any clinical benefits," Prof Murphy added.

But Dr Williamson, medical director of NHS Blood and Transplant, is sceptical.

"It is very difficult to imagine that one in five transfusions are inappropriate.

"We are much more aware of the need to make transfusions appropriate."

'Lost the plot'

The blood services have been running high-profile advertising campaigns to attract more blood donors which makes the debate over the risks of transfusion very sensitive.

Nobody wants to discourage donors but Dr Brian McClelland, strategy director of the Scottish National Blood Service said this should not get in the way of basic questions.

Operation
Transfusions have dropped in England and North Wales
"The early experiences of transfusion which led us to promote voluntary blood donation as a fantastically important life-saving contribution to your fellow man have created a belief in transfusion which has diluted the pressure which should have been there to do the clinical trials to really ask the questions.

"We question have we lost the plot in putting so much effort into safety and, until recently, so little effort into the effectiveness of blood, because without that information it is impossible to make a safe, sensible, ethical choice between the balance of benefit and risk."

Safe supply

But Dr Williamson insisted there is no need for a radical change in policy.

"It is very easy to take a safe blood supply for granted," she said.

"The UK is doing well in clinical research in general and therefore there is scope for good quality studies in transfusion as in other branches of medicine."

The argument should be settled once and for all when gold standard randomised trials are complete.

Some are planned, others are under way but it may be another five or eight years before the evidence is clear



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