A REPORT to be released today has found that severe trauma patients requiring a major transfusion are twice as likely to die if they receive red blood cells stored for a month or longer.

The study, which will be published in BioMed Central's journal Critical Care, was conducted by paediatric interns Philip Spinella and Christopher Carroll and their team from Connecticut Children's Centre, Hartford in the US.

The group studied 202 severe trauma patients treated at Hartford Hospital. They found that even one unit of red blood cells stored for more than 28 days doubled the incidence of deep vein thrombosis and increased death secondary to multiple organ failure.

"Though experts had long suspected that older red blood cells caused complications, this is one of the first studies to strongly support this dramatic link," said Charlotte Webber of BioMed.

"This has eliminated the major criticism of previous studies that it was the amount of cells transfused and not the storage age that was affecting outcomes," she said.

The study will enable doctors to reduce these risks by giving fresher red blood cells to patients who need these major transfusions for life-saving procedures.

Spinella said: "The preferential use of younger cells to critically ill patients has the potential to increase waste due to outdating.

"These findings should encourage research into the effects of old blood and coagulation in patients. With the widespread use of red blood cell transfusion for critically injured patients, this has the potential to cut deaths in hospitals around the world."