X-Message-Number: 28145
Date: Thu, 29 Jun 2006 10:12:56 -0700 (PDT)
From: Doug Skrecky <>
Subject: older stored blood increases mortality

[The F.D.A. states without evidence that stored blood can be safely
used for 42 days. This is the first actual test of this claim.
Use of blood that was stored for longer than 30 days was associated
with a 50% incidence of renal dysfunction. Renal problems had an 8%
incidence when blood stored for less than 20 days was used. This
remarkable finding points out the need for more effective blood
preservation technologies.]

http://www.nytimes.com/2006/06/27/health/27blood.html
June 27, 2006
Age of Transfused Blood May Play Part in Recovery
By NICHOLAS BAKALAR

Transfusions with blood that has been stored for long periods of time
may decrease the survival rates for seriously ill surgery patients, a
new report suggests.

In a study of patients undergoing repeat heart surgery, researchers
found that the risk of premature death, both in the hospital and
long-term, increased significantly with each day the transfused blood
had been stored. Food and Drug Administration regulations allow the
refrigerated storage of liquid blood for 42 days.

Red blood cells, the authors write, undergo significant changes during
storage, including an increase in abnormally shaped red blood cells that
may impair oxygen delivery to tissues.

But the clinical significance of the changes is not clear. In a
retrospective study of 321 heart surgery patients, the scientists found
that the rate of in-hospital death increased by 8.5 percent and
out-of-hospital death by 10 percent for each additional day the
transfused blood had been on the shelf.

"According to the F.D.A., 42-day-old blood is just as safe and effective
as 10-day-old blood," said Dr. Elliott Bennett-Guerrero, the lead author
on the study and an associate professor of anesthesiology at Duke
University. "But we are concerned that one reason why some studies show
blood transfusions to be detrimental may relate to the age of the
blood."

Rates of in-hospital mortality ranged from about 4 percent among
patients who received the "newest" blood (1 to 19 days old) to 25
percent among those who received blood that had been stored for 31 to 42
days. Blood older than 42 days is discarded.

Although the retrospective nature of the study, which appears in the
July issue of the journal Anesthesia & Analgesia, prevented the
scientists from determining the exact mechanism at work, they were able
to track kidney failure as one effect.

Transfusions with older blood were a significant predictor of
post-operative kidney function. The patients who received blood stored
for less than 20 days had about an 8 percent rate of acute renal
dysfunction, while those who received blood stored more than a month had
an almost 50 percent rate of kidney failure.

The length of hospital stay also went up consistently with the age of
the blood used.

People who received blood less than 20 days old averaged about 12 days
in the hospital; those who received blood older than one month had an
average stay of about 18 days, including twice as much time spent in the
intensive care unit.

The correlations held even after adjusting for sex, obesity, type of
surgery, number of transfusions and other variables.

"If you're getting one unit of blood," Dr. Bennett-Guerrero said, "it
probably doesn't matter much whether it's older or fresher. But if
you're getting six or eight units of blood, it might matter more whether
that blood is old."

The question of aging blood has been around for decades, Dr.
Bennett-Guerrero said.

"The main standard the F.D.A. uses is that 75 percent of transfused
blood cells have to be in circulation 24 hours after the transfusion,"
Dr. Bennett-Guerrero said. "That's why blood has a shelf life of 42
days. But there have been no trials to determine if this older blood
helps patients or is harmful."

The average age of most transfused blood, Dr. Bennett-Guerrero said, is
about two to three weeks.

"It's important to donate blood," he added. "The more people who donate
blood, the more that's in the system, and the more flexibility blood
banks have to administer fresher blood to patients."

Still, he said, he is not suggesting that current practice should be
changed on the basis of this study.

"It is one more piece of evidence," he said, "that might suggest to
clinicians that transfusing blood may not always be benign."

Dr. Bennett-Guerrero emphasized that a large randomized trial would be
required before any firm conclusions could be drawn.

"We don't know for sure that older blood is bad for you," he said. "But
we really need to know the answer, one way or the other."

[Here's the actual abstract.]

Anesth Analg. 2006 Jul;103(1):15-20
The association between duration of storage of transfused red blood
cells and morbidity and mortality after reoperative cardiac surgery.
Basran S, Frumento RJ, Cohen A, Lee S, Du Y, Nishanian E, Kaplan HS,
Stafford-Smith M, Bennett-Guerrero E.
  Red blood cells (RBCs) undergo numerous changes during storage;
however, the clinical relevance of these storage "lesions" is unclear.
We hypothesized that the duration of storage of transfused RBCs is
associated with mortality after repeat sternotomy for cardiac
surgery, because these patients are at high risk for both RBC
transfusion and adverse outcome. We retrospectively analyzed 434
patients who underwent repeat median sternotomy for coronary artery
bypass graft or valve surgery and who received allogeneic RBCs.
Three-hundred-twenty-one (74%) patients met the criteria for
eligibility. After adjusting for the effects of confounders and the
total number of RBC transfusions, the duration of storage of the
oldest RBC unit transfused was found to be associated with both
in-hospital mortality (Cox proportional hazard ratio (HR) = 1.151;
P < 0.0001) and out-of-hospital mortality (HR = 1.116; P < 0.0001).
The mean duration of storage of transfused RBCs was also an
independent predictor of in-hospital mortality (HR = 1.036;
P < 0.0001). Independent associations between the duration of
storage of transfused RBCs and acute renal dysfunction and intensive
care unit and hospital length of stay were also observed. The
duration of storage of RBCs is associated with adverse outcome after
repeat sternotomy for cardiac surgery. The clinical significance of
this finding should be investigated in a large, randomized, blinded
clinical trial.

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