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Blood-filtering program saves lives, improves health outcomes, Ottawa researchers find

OTTAWA - A major nationwide study led by researchers at The Ottawa Hospital has found that a program to filter out white blood cells from donated blood can save lives and results in fewer fevers and decreased antibiotic use in high-risk patients.

A second major study, also led by Ottawa Hospital researchers, found a significant decrease in serious complications related to prematurity in newborns who received leukoreduced blood, where white blood cells have been removed.

Both studies are reported in this week's edition of the Journal of the American Medical Association.

In our own bodies, white blood cells help fight disease and infection. But when they are transferred to another person's body by way of a blood transfusion, they can actually suppress the immune system, resulting in infections.

A number of countries, including Canada, have implemented a policy of universal leukoreduction of all donated blood. Although policy makers believed in the benefits of leukoreduction, its role in decreasing mortality and infection rates in surgical patients was previously unproven.

The first study, led by Ottawa Hospital intensive care physician Dr. Paul Hébert, a Senior Scientist in the Ottawa Hospital Research Institute (OHRI) and director of the University of Ottawa Centre for Transfusion Research, involved 14,786 post-operative patients from 23 hospitals across Canada, including The Ottawa Hospital. The study involved patients in three high-risk groups who typically require transfused blood: heart bypass surgery patients, patients undergoing hip surgery and postoperative and multiple trauma patients admitted to an intensive care unit.

Of the patients involved in this study, approximately half received their blood transfusion before leukoreduction was put into practice, while the other half received leukoreduced blood products.

The researchers found that death rates of hospitalized patients were lower following the introduction of leukoreduction compared with the control period. They also found an important decrease in the number of patients with fever and in the use of antibiotics.

The researchers estimate that one life would be saved for every 120 patients who receive leukoreduced blood. "Considering the number of people transfused every year, the near 1% decrease in deaths represents a lot of potential lives saved," said Dr. Hébert. "I believe that we found nothing but potential benefit. The adult study adds to the evidence that leukoreduction is a beneficial strategy in the processing of blood."

A second study led by Dr. Dean Fergusson, a scientist with the OHRI and an epidemiologist with the University of Ottawa Centre for Transfusion Research, involved 515 premature infants weighing less than 1,250 grams (2.8 lbs) who were admitted to neonatal intensive care units (NICU) at three Canadian hospitals. One in two infants weighing less than 1,250 grams at birth who are admitted to NICU's require blood transfusions.

The researchers found that nearly 30% of the infants who received transfusions before leukoreduction acquired a blood-borne bacterial infection compared to about 26% of infants who received leukoreduced blood. More significantly, leukoreduction was also associated with a substantial reduction of complications of prematurity, including chronic lung injury, inflammation of the bowel, internal bleeding in the head, and retinopathy, or injury to the retinal tissue.

"For every 10 infants you treat with leukoreduced blood, you prevent one serious complication of prematurity," Dr. Fergusson said. Both studies suggest that white blood cells may promote inflammation and cause damage to otherwise normal cells and tissues in premature babies.

The authors conclude that, until there is evidence of harm, all infants requiring red blood cell transfusions should receive leukoreduced blood. This could revolutionize transfusion practices for premature infants in countries that have not yet adopted universal leukoreduction.

The Canadian Institutes of Health Research and Canadian Blood Services funded both studies. In addition, Héma-Québec provided funding for the Adult Leukoreduction Program Evaluation.

About the Ottawa Hospital Research Institute:

The OHRI is the research arm of The Ottawa Hospital and a major part of the University of Ottawa Faculty of Medicine and Faculty of Health Sciences. With more than 200 scientists, 225 students and 400 support staff, and $42 million in external funding, the OHRI is one of the fastest growing and most respected hospital-based research institutes in Canada.

Media contacts:

Sharon Kirkey
Communications Officer
Ottawa Hospital Research Institute
(613)798-5555 ext. 17840

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