TIME: Why Banked Blood Goes Bad (US needs donors!)

[Omaha Steve]

I became a regular blood donor after 9-11. Our union contract allows us to do this on company time as a public service.

http://www.time.com/time/health/article/0,8599,1669438,00.html

By ALICE PARK

It's been called the gift of life, but for many of the five million patients who receive blood transfusions every year, it can actually do more harm than good.

It's a problem that doctors have been wrestling with for several years, as study after study shows a disturbing spike in heart disease and death in patients receiving transfusions. The trend affects almost every group of critically ill patients — from trauma sufferers in the ER to heart attack victims, patients with anemia and those undergoing chemotherapy. This increase in death and heart disease, doctors say, is unrelated to infectious blood-borne diseases or allergic reactions that often follow transfusions. "After you control for sickness and all sorts of things, patients who receive transfusions still have more heart attacks. It makes no sense," says Dr. Jonathan Stamler, a professor of medicine at Duke University Medical Center.

Logically, and medically, patients who need transfusions — those with low blood counts — should benefit immediately from a transfusion of new oxygen-laden red blood cells. Yet many get sicker. Puzzled by the paradox, Stamler and his colleagues decided to look more closely at banked blood — to figure out whether it underwent certain changes that turned it from life-saving in the donor to potentially deadly in the bag.

Their finding, reported this week in the Proceedings of the National Academy of Sciences: nitric oxide (NO). A workhorse of the blood, the gas helps red blood cells ferry oxygen to tissues and props open tiny vessels to allow freer blood flow. It turns out that within hours of leaving the body, levels of nitric oxide in the blood begin to drop, until, by the time donated blood expires after 42 days, the gas is almost nonexistent. "The reality is that we are giving blood that cannot deliver oxygen properly," says Stamler, lead author of the study. "Many patients who are getting blood are being put at increased risk."

Previous trials have shown that heart disease patients, for example, who receive a blood transfusion to help restore oxygen to deprived tissues, have a 25% chance of having a heart attack and an 8% chance of dying within 30 days; similar patients who do not get transfused have an 8% chance of a cardiac event and a 3% chance of death. Stamler hypothesizes that without NO, red blood cells cannot drill their way into tiny blood vessels; rather, they pile up in narrow passageways, blocking blood flow instead of increasing it and hampering the heart.

FULL story at link.