MONDAY, Oct. 8 (HealthDay News) -- When premature babies need blood transfusions, older blood appears as good as "fresh" blood, Canadian researchers report.

The researchers found no difference in outcomes, either with complications or death, between the two. Fresh blood has been stored for a week or less; blood is typically kept and used for a month or more.

"The current transfusion [guidelines] for neonates shouldn't change," said lead researcher Dean Fergusson, from the Ottawa Hospital Research Institute.

There have been pressures recently to use only fresh blood for newborn transfusions, he explained, although "it's largely based on shaky data from less robust studies. We have done a clinical trial showing absolutely no difference between the way things are normally done versus a fresh-only group."

People assume that "fresh is better," Fergusson said. This assumption was based on what appears to be deterioration of red blood cells as they age, making them less able to carry sufficient oxygen to the cells of the body, he explained.

"What happens is ... the red cells come back to life and do deliver oxygen as soon as they are transfused," he said.

Fergusson was surprised by the result. "I went into this thinking fresh would be better," he said.

These results should be reassuring to patients and doctors, but especially to blood banks, Fergusson said.

"We currently shelve blood for 35 to 42 days," he said. "If we had to change the system to less than seven days, the number of donors would go through the roof and the wastage would go through the roof."

Fergusson said he expects this finding will be upheld in ongoing clinical trials with cardiac surgery patients, cancer patients and elderly patients, where the use of older blood has also been a topic of debate.

The report was published online Oct. 8 in the Journal of the American Medical Association, to coincide with the annual meeting of the AABB (formerly the American Association of Blood Banks), in Chicago.

To find out whether transfusing with fresh blood was better than older blood, Fergusson's team randomly assigned almost 380 underweight premature newborns who needed transfusions to receive blood stored for a week or less or blood stored for two weeks or more.

Among these infants, the researchers looked for any major illness or death.

They found almost 200 infants had a major illness or died. Of these, 99 were in the group receiving fresh blood and 100 were in the group receiving older blood.

Specifically, there were 146 infections in the group given fresh blood, and the same number in the group given older blood. These similarities were for confirmed infections, and in the rates of bacterial, fungal and viral infections as well, the researchers found.

Complications from infections such as pneumonia, meningitis and osteomyelitis, an inflammation of bone or bone marrow, also were similar between the groups, they noted.

One expert agreed that the current blood-donation system doesn't need to be changed, but added that the study doesn't definitively answer the question about the benefit of fresh versus older blood.

The current standard treatment for infants is to use blood that is less than 28 days old, said Dr. Hernan Cruz, academic director of the neonatal intensive care unit at Miami Children's Hospital.

"Most of the babies in the standard group were transfused with blood that was not that old -- an average of 14 days," Cruz said. "That makes the conclusion a little weak. Whether there is a benefit of using fresh blood versus old blood is still a debate."

More information

For more on blood transfusions, visit the U.S. National Heart, Lung, and Blood Institute.