10-21-2007, 02:37 PM
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Here's a video of Dr Stamler talking about the problem with nitric oxide depletion in stored blood.
YouTube - Duke studies: Banked blood doesn't deliver oxygen
What the public and many health professionals are unaware of is that even if they solve this problem by perfusing stored blood with nitric oxide (a free radical that can damage body cells) stored blood is still unable to oxygenate the tissues efficiently. There are two additional reasons for this.
1) Stored blood lacks adenosine triphosphate (ATP), a substance that helps fresh red blood cells to maintain their deformability. Red cells need to be deformable, that is, to change their shape from round to torpedo-shaped so as to be able to navigate capillaries that narrow down to 6 or 7 microns. If the cells lose their deformability they will get stuck in the capillaries and not reach the tissues with their precious oxygen load.
2) Stored blood lacks 2,3-diphosphoglycerate (2,3-DPG), a chemical that "tells" the hemoglobin in the red blood cells to offload its cargo of oxgen to the tissue beds. Insufficient 2,3-DPG will result in the oxygen being carried by the blood remaining unavailable to the body's cells and organs. In this circumstance, carbon dioxide is not carried away and toxic wastes can build up in the system.
Thus, banked blood may be little more than a volume expander in an emergency. Clinical studies have also shown that banked blood may do more harm than good in critically ill patients. Meanwhile this dangerous product, of dubious effectiveness, continues to be given to patients by healthcare professionals with scant regard for the consequences -- short- or long-term.
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