Blood Transfusion Safety

(Ivanhoe Newswire) -- Each year about 350,000 coronary artery bypass graft surgeries are performed. For those patients who have repeat procedures, blood transfusions are routine. Now, doctors are asking how safe it is to use blood that has been sitting on a shelf for those procedures.

For years, doctors have known red blood cells change the longer they sit waiting to be used, but, until now, studies have not looked whether these changes could prove fatal.

Researchers from Duke University Medical Center in Durham, N.C., and Columbia University in New York performed a retrospective study to look at heart surgery patients' outcomes following a transfusion as compared to the time the blood was stored. They divided the blood into four different groups up to 42 days old, the limit national blood banks place on storage time.

Lead author Elliott Bennett-Guerrero, M.D., and colleagues expected to see increased complications among patients who had repeat surgeries and, therefore, multiple transfusions.

The findings, as published in Anesthesia & Analgesia, indicate a small connection exists between older stored blood and increased risk of death both during the hospital stay as well as after discharge. In addition, the researchers discovered older blood could also lead to kidney problems, acute respiratory distress, and longer time spent in intensive care. Dr. Bennett-Guerrero points to the importance of looking at the number of transfusions given as another risk factor for complications.

Of the 321 patients whose cases they looked at, only 4 percent of those who received the "freshest" blood died while in the hospital compared to 25 percent of patients who received the oldest blood. The former also spent an average of 3.5 days in intensive care compared to 17 days for the latter.

Researchers believe the older blood may be dangerous due to the loss of ability to carry oxygen as well the possibility that it may stimulate an immune response. Additionally, with time, red blood cells tend to become stiff and may not be able to fit through capillaries to deliver oxygen.

Based on their findings, researchers believe a larger, randomized study is warranted.

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SOURCE: Anesthesia & Analgesia, 2006;103:15-20