Transfusions bring experts' blood to boil

Refuse at your own risk. For years that’s the message medical practitioners have relayed to Jehovah’s Witnesses and others who’ve declined blood transfusions on religious grounds or otherwise.

Now retrospective studies have shown that not only have outcomes for Witnesses’ who refused blood transfusions been no worse than their counterparts who received them, in some cases they’ve actually fared better.

Transfusions, as it turns out, are not the wonder procedure they’ve been mythicised as. Mounting evidence shows they significantly increase the risk of post operative complications including infections, kidney failure, lung injury and death. Yet instead of being saved as a last resort they are still being performed when other safer options could be used instead. In fact more than a quarter of blood transfusions currently performed are “unnecessary” according to experts who spoke at the annual scientific meeting of the Australian and New Zealand College of Anaesthetists (ANZCA) two weeks ago.

Internationally renowned emergency medicine and anaesthiology professor Bruce Spiess told the conference that while blood transfusions have long been “believed to be helpful and a pillar of modern medicine” there’s relatively little evidence to support such claims.

 “Drug options are carefully tested and regulated through prospective, randomised double blind testing, but blood transfusion stands apart,” he says. “It has never been safety or efficacy tested,” he says.

It’s a point that has been echoed by several Australian experts including anaesthesists associate professor Larry McNicol and Dr Peter McCall at Austin Health in Melbourne.

“From the point of view of the risk of transmitting infections, blood transfusions are safer than they have ever been. However there is an ever increasing body of research about adverse outcomes in association with them,” McCall says. “Still there is a tendency to think that blood transfusions are mystical and lifesaving and it is better to give them than to withhold them.”

The reasons not to make blood transfusion the default are becoming increasingly apparent: A person who has had a blood transfusion after surgery has up to four times the risk of wound infections. People who have blood transfusions during cancer surgery face up to twice the risk of the cancer recurring.

In his presentation to ANZCA, Spiess discussed Swedish research on cardiac patients that compared Jehovah’s Witnesses who refused blood transfusions to patients with similar disease progression during open-heart surgery—the research found the group who had refused transfusions had noticeably better survival rates.

There are a few major reasons complications rise following transfusion. For one thing immune response is impaired as the body responds to the blood as a foreign body, much in the same way it responds to a transplant, experts say. The properties of red blood cells also become altered when blood is stored, reducing their ability to distribute oxygen through the body.

Yet at least 25 per cent of transfusions that are done could be avoided, Spiess says.

A 2005-2006 audit of the use of fresh frozen plasma in hospitals in Tasmania and Victoria found that a third of the transfusions performed were “inappropriate,” according to the 2001 guidelines issued by the National Health and Medical Research Council, says associate professor Larry McNicol, who also chairs the Better Safer Transfusion program run by the Victorian State Government that sponsored the research. 

“Essentially these patients really perhaps didn’t need it and there might not have been therapeutic benefits,” McNicol says.

Which is not to say that’s always the case. There are still circumstances when blood transfusion is absolutely necessary—and the patient would likely die if they did not receive one, says University of Sydney professor James Isbister, a consultant on haemotology and blood transfusion who chairs the Red Cross advisory board. Isbister says blood transfusion can be vital for patients who are undergoing major surgery after experiencing major trauma or shock when there is major bleeding that is difficult to control quickly. It can also be instrumental in managing hemophilia, where blood does not clot, as well as acute hemorrhages.

“A lot of major surgery would never have developed without the possibility for blood transfusion either, for instance open heart surgery,” Isbister says.

But many of the cases in the Better Safer Transfusion audit involved transfusions that could have been avoided. For example it was once thought that blood transfusions should be performed any time a patient’s hemoglobin level dipped below 10—but now guidelines in varying countries put the number between 6 and 8.

"It used to be that 10 was the acceptable minimum but now we know that patients are at no detriment by a running a lower count and we can avoid these additional risks,” McCall says. “When the blood count is lower the heart is able to beat more strongly so it can actually pump more efficiently to distribute the blood better.”

The audit also uncovered a tendency for some doctors to use transfusions as a precaution in patients who were at risk of bleeding, but not actually bleeding—for example they might have had abnormal test results. In those cases the guideline recommended approach is to wait and see if the person actually does start to bleed first.

Other studies have shown that the likelihood of receiving a transfusion during elective orthopaedic surgery or cardiac surgery can vary enormously between hospitals despite there being little difference between the patients themselves, Isbister says.

“There’s huge variation between hospitals and surgeons depending on where you have your operation—in one hospital you can have an  80 per cent chance of being transfused  and in another hospital 10 per cent chance—that’s based Austrian research in 15 hospitals but observations and audits in Australia have also found big variations,” Isbister says. “Most patients undergoing hip and knee surgery should only have a 10 to 20 per cent chance of needing a transfusion—but there’s evidence it can be much higher.”

There are a number of ways to lower the numbers of transfusions that occur. “There are a lot of quite good alternatives,” Isbister says. They include drugs that

that minimise blood loss and drugs that stop clots from being dissolved as well as anesthetic and surgical techniques to minimise blood loss.

“For example you don’t always have to bring a person’s blood pressure up to normal—you can keep it low and that minimises bleeding,” he says.

In surgery where there’s a risk of major blood loss doctors frequently use  a technique called “red cells salvage” which allows them to reuse the patient’s own blood rather than transfusing someone else’s. The patient’s blood is collected in a machine where it is then washed in a saline solution to remove any impurities before being given back to the patient.

But the battle to reduce unnecessary transfusions often begins before surgery even occurs.

“One of the ways to minimise transfusions is to prepare patients better before surgery—for example you can give them supplements to get their blood count up before surgery,” McCall says.

To that end a 2005 South Australian audit found that 18 per cent of people who had been on waiting lists for elective surgeries had anemia, which increases the chances of needing a transfusion. If the anemia had been better managed before the surgery some of those patients could have avoided blood transfusions, according to Kathryn Robinson, medical advisor of South Australia’s BloodSafe..

But for all the bad news, experts say that change is on the horizon—the high profile position the issue was given at the ANZCA conference is just one sign of that, as anaethesists perform more than half of all transfusions, McNicol says. States across Australia are developing initiatives to help decrease unnecessary transfusions. Meanwhile at a conference of federal and state health ministers in late March the federal government it would fund two major initiatives that are expected to improve the safety of the blood supply itself and improve outcomes for those people who do ultimately need transfusions.

One of those initiatives is the universal testing of platelets, which carry particularly high risks of complications. Unlike other blood products, platelets can’t be refrigerated, so they are susceptible to contamination by bacteria—international best practice guidelines recommend all platlets be universally tested for the bacteria, but currently only about 5 per cent of the supply is tested, McNicol says.

At the same meeting the government announced that by 2010 all blood will be processed to remove white blood cells, known as leukoreduced blood, which has been shown dramatically reduce complications and is already in widespread use  in Canada, New Zealand, Western Europe and elsewhere.

The problem is that the white blood cells go into the bone marrow and depress the recipient's ability to fight infection, Spiess says.  

“There are three randomized controlled studies in heart surgery, where patients who were deemed appropriate to be transfused got either leukoreduced blood or blood with white cells present. The death rate in those with leukoreduced blood was roughly half that of what it was in those with blood with white cells,” Speiss says. “What was not randmomized but was still there in these studies was that in the patients that got no blood there were no deaths at all!”


 Copyright Lynnette Hoffman for The Australian, 2007.