NO laughing matter

NO2 is the chemical makeup of nitrous oxide, the "laughing gas". NO is the chemical makeup of nitric oxide, a key component, so it now appears, in delivering oxygen via the blood system.

Banked Blood Could Do More Harm Than Good

Two US studies suggest that almost as soon as it has been donated, banked human blood loses the vital ability to transfer oxygen to body tissue that desperately needs it. The researchers say that for the majority of patients, blood transfusions with banked human blood could do more harm than good.

Almost immediately after it leaves the body, human blood begins to lose an essential gas, nitric oxide which is believed to be crucial to the delivery of oxygen to tissues because it keeps the tiny blood vessels inside the tissue mass open. The researchers also believe that it helps red blood cells to stay flexible so they can easily fit into the narrow constraints of the blood vessels.

But while scientists knew that banked blood was not the same as the blood in the body they did not know why it should carry these risks.

To test whether putting nitric oxide back into the stored blood would affect its ability to supply oxygen, Stamler and his team used dogs.

They showed that when they gave stored blood to the oxygen deprived animals, the blood flow did not increase properly. Yet paradoxically stored blood is often given to heart patients to prevent heart attacks. This experiment showed that doing this could actually be increasing the risk of a heart attack.

When they added nitric oxide to the stored blood they gave to the dogs, blood flow to the heart was increased, indicating the blood vessels were sufficiently dilated to allow passage of the blood cells and oxygen transfer to take place.

"This suggests that adding nitric oxide to human banked blood could theoretically improve its ability dilate blood vessels and thus prevent heart attacks and even death in patients," said the researchers.

A large-scale randomized clinical trial in humans is needed, said McMahon and Stamler. These studies show that donated blood has risks as well as benefits, and therefore should undergo clinical trials in the same way as drugs and medication.

Officials: Transfusions valuable
By Melissa Dunson

The danger in not having enough nitric oxide in transfused blood is that without the component, the vital blood cannot get to the tissues that need the oxygen.

“If the blood vessels cannot open, the red blood cells back up in the vessel and tissues go without oxygen,” said Dr. Jonathan Stamler of Duke University, leader of one of the research groups. “The result can be a heart attack or even death.”

Chris Pilgrim, marketing manager for the blood center, acknowledged the need to further examine the issue of degrading nitric oxide, but said the historical importance of blood transfusions should not be undermined.

“There has been some study that shows there is some degradation of the blood when it is stored, but nothing can replace blood transfusions,” Pilgrim said. “There is no alternative to blood, and, unfortunately, it has to be stored.”

Thomson said the decision by doctors to transfuse blood is always a risk-versus-benefit analysis, and when someone is seriously injured and needs blood, the benefits almost always far outweigh the risks.

Guambat is aware that blood collection, even by "non-profit" organisations, is big business, just as is every other aspect of modern medicine. There will be a clamor over this as the vested interests spin and defend, but it appears these studies point to a fix of the problem, and that can only be a good thing when that is finally worked out.