Banked Blood May Not Be As Effective As Hoped 116
URSpider alerts us to two separate research reports published in the Proceedings of the National Academy of Sciences pointing to the rapid breakdown of nitric oxide in donated blood as a reason why such blood loses its ability to transfer oxygen, and is sometime implicated in problems such as strokes and heart attacks. Nitric oxide depletion is significant after 3 hours of storage; yet current guidelines allow for storing donated blood for up to 42 days. The article notes: "Several of the researchers, including Stamler, have consulting and/or equity relationships with Nitrox/N30, a company developing nitric oxide based therapies."
WARNING - May be Dug Company Propaganda! (Score:5, Informative)
Wrong Chemical in summary (Score:5, Informative)
This is not a new concept (Score:4, Informative)
It's well known that packed red blood cells or whole blood is not as effective as fresh blood at transporting hemoglobin. This is because of several factors, notably shifts in 2,3-BPG, ATP, ADP during storage as well as partially due to the calcium citrate used to prevent clotting of the stored blood.
While it isn't ideal, our current method is by far the safest way to give blood, simply because you cannot screen blood for deadly pathogens in the time it takes for blood to start to degrade. While many people have researched ways to shift the binding characteristics of stored blood back to fresh blood, and with some success on manipulation of hemoglobin's oxygen binding curves, overall the clinical effect for patients has been minimal.
The nitrous-oxide pathway, to my knowledge, has not been tried yet, but I'd hate to have my blood pre-mixed with a drug that would kill a percentage of the patients who are candidates for blood transfusion. When someone is exsanguinating, you want to INCREASE their blood pressure, not decrease it.
On the other hand, in ischemic disease you do want to give nitro, in certain situations, but preferably not pre-mixed with the blood, and we already do this, just not in strokes, yet.
Re:pros and cons (Score:5, Informative)
The problem listed in the article is an increase in heart attacks and strokes post-transfusion. Time's more complete article [time.com] says that 25% of blood donor recipients have heart attacks within the 30 days post-transfusion, as opposed to 8% of patients who came in to the emergency with similar conditions, but did not get a blood transfusion.
When the problem shows itself over the 30 days post-transfusion, it can be hard for medical researchers to notice and research the issue. I'd suggest (assuming this research has been done properly), having my probability of MI increase from less than 1 in 10 to 1 in 4, would make me want them to consider altering the requirements, whether it be by providing more new blood, or by artificially adding Nitric Oxide (not Nitrous Oxide, as the summary claims).
more than just bias that I would be concerned abou (Score:3, Informative)
Well, not having read the study I can not comment on its significance; however, there is far more to blood transfusion dangers than NO depletion.
Lets get to some significant points: NO is produced locally at the tissues that need it.
RBC fragility is likely more significant than the effects of one vasodilator
Multiple unnecessary (or necessary) transfusions may lead to iron overload similar to that found in people with hemachromatosis
TRALI
I am not attacking their work, but there are so many other reasons to be vary of transfusions - the significance of this one seems like it would be minimal, but I do applaud their work in trying to minimize complications of transfusion.
Re:Got a lot to learn (Score:5, Informative)
Even now, blood transfusions are only used by doctors in the most critical situation and yes, storage and transfer of blood as well as the necessary screenings make it very difficult to get a 1) cheap and 2) reliable source of blood.
Some doctors even don't use blood transfusions at all (there are even some hospitals that don't give any blood for any reason) and use substitutes like volume expanders or oxygen carriers to get what the body needs (either a larger volume of blood or more carriers so a subject doesn't asphyxiate) or they use only parts of the blood that are deemed necessary (for example to clot your blood faster) and that are more safe than blood.
Blood is considered an organ, with transfusions you get issues like rejection just like you get (often) with liver transplants and giving somebody a large amount of foreign blood could also result in shock or death.
NO dilates blood vessel and not always desired. (Score:5, Informative)
In natural circumstance, for exemple, it is produced during effort to divert blood to region where it is needed (because the adrenaline has a global effect of closing the blood vessels).
In medicine, products that create NO like Nitroglycerin are used to dilate vessels and increase blood flow to the heart in case of angor (not enough blood in the heart muscle because of cholestrerol-clogged arteries).
Sildenafil (Viagra) is an inhibitor which stops the destruction of NO, thus maintaining enough level of NO, so the vessels are dilate and there's enough blood flow to fill the penis and provide erection.
Yes, if there's not enough NO, a stroke may appear. That's why Nitro-glycerine is given to avoid it.
Yes, transfused blood is more dense than other substance that can be injected to compsensate blood loss (other substance = Ringer solution = physiological serum = basically isotonic sterile salty water with some additional sugar thrown in). And this increased viscosity may increase the risk of stroke.
Now, just concentrate for a moment : to whom are you going to transfuse blood / perfuse physiological serum ?
People who lost a lot of liquid (bleeding wounds, burns, etc.).
Why ?
Because their blood pressure is dropping and there is a risk of shock (= schematically, not enough blood pressure to irrigate brain and other important organs).
Now, all
Now to go back to the situation, all the people from the study cited by the Times had (supposedly - didn't read the actual study yet) low blood pressure. Some got blood transfusion, other did not (I suppose they recieved physiological solutions instead).
25% of the blood reciever had heart attacks.
It may be caused, as the sponsor would like us to believe (the company makes NO products), because NO binds to hemoglobine [wikipedia.org] and helps releasing oxygen. And thus the transfused blood was useless because it didn't have enough NO to release enough oxygen. In this case we should buy the company's NO products.
BUT
- Why didn't the physiological receiving patient had problems ? Physiological serum doesn't carry oxygen at all. If NO-less blood is useless at transporting oxygen, non-oxygen-transporting solutions should too...
- Where they compared against a 3rd group receiving only fresh (NO-rich) blood ? No. Where they compared against 4th group receiving NO enriched non-fresh blood ? No, this was only done in lab rats.
- NO is something produced by the body when needed and has a short life (3 hours as they said in stored sample). Presence or absence of NO in the blood can hardly explain stroke happening 30 days later, after 3 hours the NO contained in the transfused blood is already degraded and replaced by NO produced by the patient.
- Other ligands can also increase release of O2 : temperature, CO2, products of degradation of glucose. Hemoglobine has a lot of different way to guess that some body regions are burning a lot of oxygen and that the hemoglobin-bound oxygen should be released more easily.
- Also note that their explanation can only account for the brain hypoxia (lack of oxygen), not the stroke itself (clogged vessels).
On the othe
NO, pills and even some blood doping info (Score:3, Informative)
http://en.wikipedia.org/wiki/Endothelium-derived_relaxing_factor [wikipedia.org]
There are ways of going around this, like taking nitroglycerin pills
http://en.wikipedia.org/wiki/Glyceryl_trinitrate_(pharmacology) [wikipedia.org]
Blood doping works. But problem is that viscosity increases and you can crap out. Essentially, blood doping is putting a huge strain on your circulatory system so that there is a little more gas in the tank. Really bad idea. Just like taking steroids. You can crap out anytime.
Re:pros and cons (Score:3, Informative)
I work for the American Red Cross (Score:5, Informative)
I work in I.T. for ARC, but previous to that, I worked on the front lines, collecting the blood.
Allow me to give you a mini-tour.
First, the donor is required to read and acknowledge that they've read the health history guidelines.
Then the donor is required to get their vitals checked, answer several health related questions.
At that point the donor is placed on the donor bed. Their information is rechecked for accuracy.
Their arm is scrubbed using a two-step method.
The venipuncture is performed.
Now here's the important part. The blood comes into the bad which is filled with an anti-coagulant solution, and for it to be a "good unit"...we can only collect so much blood/per anti-coag...the entire unit is measured by weight @ 610g +/- 5% (for a proper whole blood to anti-coag solution). I may be slightly off on the ratio, it's been a while.
Then the unit is packed on ice, and maintained at a constant temperature.
Then the blood goes to the production lab, where the platelets and plasma are expressed and harvested for other uses.
The red blood cells are then introduced to a red cell preservative, (this is the part that makes the blood viable for 42 days)
The units are then either flash frozen, or they're placed in quarantine until the test results are back from the NTL (national testing lab).
but here's the chink in the armor of the original poster's argument. Our blood supply is so low right now in the US, that his argument is a moot point. 99% of the time, the blood isn't even on the shelf that long. Every 2 seconds, someone in the U.S. needs a transfusion of packed red cells....someone like me, who is 0-, CMV-.....I'm pretty much fucked....there won't be any blood available for me. (so all you O-'s...please go donate...lol)...
Anyway....yes, units do lose their potency over time...but part of the process is to ensure that the donor is healthy, and this helps ensure that when the blood is needed it will be as potent as possible.
At the American Red Cross, we make every effort to make sure that there's blood available when it's needed, where it's needed, and provide the best quality units, at the cheapest price, and make every effort to ensure that it's potent, and safe....that's from the very top of the food chain all the way down the janitors...we all love what we do, and we save lives.
That's not to say that occasionally there might be a 1/1,000,000 unit that didn't do the job, but I like those odds