Old Blood Is Bad Blood: Study

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(newser) – Donated blood may have a much shorter shelf life than

previously thought, finds a study published today in the New England

Journal of Medicine. Transfusions using blood at least two weeks old

increased heart-surgery patients' post-operative death risk by 30%,

researchers discovered, though the current expiration date for blood is 6

weeks after donation, reports USA Today.

The Cleveland Clinic team focused on heart patients around 70,

prompting calls for additional research into other uses of donated blood.

The American Red Cross calls the study " provocative, " but

cautions that " it's not really appropriate to conclude that old

blood is bad. " The next step will be a rigorous clinical trial, says

the study's author.

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USA Today

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Older donated blood tied to heart surgery risk

 

Study backs fresher transfusionsBy

Stephen Smith

Globe Staff / March 20, 2008

Patients undergoing heart surgery routinely receive blood that has sat on

a refrigerator shelf for two weeks or longer, a practice that appears to

heighten their risk of infection, kidney failure, and even death,

according to a major new study.

 

 

more stories like thisThe sweeping

report in today's New England Journal of Medicine found that the age of

donated blood may prove more critical than previously recognized.

Scientists from the Cleveland Clinic discovered that cardiac surgery

patients who received blood that was more than two weeks old were 30

percent less likely to be alive a year later than those transfused with

fresher blood.

" It's like produce or meat - it has a limited shelf life, " said

Dr. Colleen Gorman Koch, who directed the research.

Specialists said the findings underscore the need to minimize

transfusions, boost the stockpile of donated blood, and consider making

sure the freshest blood gets to patients who need it the most.

Chronically in short supply, blood can be stored for up to six weeks

before federal rules dictate that it must be discarded.

" Increasingly, there's awareness that blood transfusion is not a

free lunch, that there are quite significant hazards associated with its

use, " said Dr. James Rawn, director of the cardiac surgery intensive

care unit at Brigham and Women's Hospital. " The importance of this

study for me as a practitioner is to more strongly confirm that, ideally,

we'd like to do heart surgery without giving any blood

products. "

The study, which tracked 6,002 patients who underwent bypass or valve

replacement surgery, is believed to be the largest attempt ever to

measure whether the age of donated blood affects the well-being of

recipients.

Like sutures and scalpels, sacks of blood are a prominent feature in

hospital operating rooms, with nearly half of all heart patients getting

at least one pint. Surgeons have historically not known the age of the

blood they are giving, and it's generally impossible for patients to have

any control over the blood they receive.

Scientists have known for a while that the longer blood sits unused, the

more it degrades. Doughnut-shaped red blood cells inexorably lose

flexibility, until they become more like stale doughnuts, incapable of

traveling efficiently through narrow blood vessels. They also forfeit

their ability to efficiently deliver oxygen to tissue, depriving organs

of the fuel they need and putting them at risk of failure.

When blood is fresher, " it's as if you rent a truck and you have

something which has a ramp, as opposed to having to lift it up and

lug " in oxygen, which is the case with older blood, said Dr. Susan

Shurin, deputy director of the National Heart, Lung, and Blood

Institute.

The six-week expiration date, specialists said, reflects a variety of

biological considerations, as well as the vagaries of blood supply and

demand. For example, Shurin said, the longer blood is stored, the greater

the prospect that bacteria multiply, even during refrigeration. Those

concerns, she said, become sufficiently worrisome by six weeks to

restrict use of blood.

 

Each year, more than 14 million units of blood are given to patients in

the United States. To manage supplies and avoid having to throw any of it

out, blood banks typically distribute the oldest blood first. Doctors

already try to minimize transfusions during surgery by, among other

things, conserving, cleaning, and returning a patient's own

blood.

 

more stories like thisThe Cleveland

Clinic scientists focused on patients undergoing heart surgery, a group

that consumes a substantial share of the nation's blood supply.

The researchers followed patients who had surgery between June 1998 and

January 2006, noting - but not controlling - the age of the blood they

received. About 3,100 got blood stored for more than 14 days, while

nearly 2,900 got the fresher blood. Nationally, among heart surgery

patients who need transfusions, half get blood stored for 15 days or

longer.

The scientists hunted for other factors that might have explained why the

patients who got older blood fared worse, but the more they looked, the

more they returned to the age of the blood as the probable

culprit.

To be sure, the vast majority of heart surgery patients were still alive

after one year, regardless of what type of blood they got. Still, there

was a statistically significant difference: Nearly 93 percent of patients

who got the fresher blood were alive, compared with 89 percent of those

whose donated blood was older than two weeks.

Similarly, the patients getting older blood were more likely to suffer

kidney failure (2.7 percent versus 1.6 percent) and serious infections (4

percent versus 2.8 percent). " I have to say, " Koch said,

" I wasn't entirely surprised. "

Dr. Richard Benjamin, chief medical officer at the American Red Cross's

national headquarters, described the study as " provocative . . . it

certainly shows quite a strong result. "

But, he said, the report falls short of being definitive because it does

not represent what scientists consider the gold standard of research: a

randomized clinical trial. In such a study, researchers in advance would

divide patients into a group that, in this case, would get newer blood

and a second group that gets older blood.

Until such a study is completed, Benjamin said, it's too soon to alter

policy on blood use.

" We struggle every day to gather enough blood to meet the country's

need, " said Benjamin. " Any recommendation that suggests that we

should not use some of the blood that we collect today is going to

exacerbate those shortages. "

The Food and Drug Administration, which establishes the nation's

blood-use policy, expressed a similar sentiment in an e-mailed statement,

saying that " while physicians may wish to consider these findings in

making treatment decisions, regulatory actions are premature pending

availability of more definitive scientific information. "

Specialists said the findings regarding heart patients are not

necessarily applicable to other people needing transfusions. That's

because patients with cardiac conditions tend to be older and suffer a

constellation of health problems. In contrast, an otherwise healthy

patient who needs a transfusion to treat, say, anemia might do fine with

blood that has been sitting around longer.

That suggests there may be a better way to manage the nation's blood

supply - giving the freshest blood to those who would benefit most -

according to an editorial accompanying the study and specialists, who

said they were unaware of any hospital routinely doing this.

" The question is, are you getting as much bang for the buck as you

could and in what circumstances do you need more bang for the buck? "

Shurin said. " Someone whose organ system is on the brink may have

much more need for a red blood cell that's in the prime of its life as

opposed to a red blood cell that's been through the mill a little bit

more. "

Stephen Smith can be reached at

stsmith.

 

 

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