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Age of blood


kriti

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In light of the recent article in the New England Journal of Medicine regarding the age of blood used for cardiac surgery, does anyone currently have SOPs/protocols or thoughts with regard to setting criteria for certain patient populations, or is anyone waiting for additonal studies prior to making a decision?

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I worked with Prof Jim Isbister in OZ. He is a very dedicated transfusionist, and understands all angles of the business, so for him to come out with this, I feel we shoould take notice. However, it will cause a supply problem if we go off half cocked, so will wait and see for the moment.

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We have a large cardiac surgery program for both adult and pediatric patients. Currently we use blood <7 days old for our pediatrics that go on bypass during surgery. Once the child is out of surgery we drop the < 7day requirement. Also, children on ecmo get <7day old RBCs always. We do not do this for Adult cardiac patients but I'm sure we'll hear about the article from the surgeons soon!

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It is becomming time for all hospitals/transfusion services to think ahead----not only is the supply of even 'old' blood been in danger because of donations going down, new diseases, old diseases, things like TRALI, and worring about pandemics, terrorism, etc---if you wait long enough, hospitals will be forced into formal conservation, rather than moving toward them now. I, for one want the best my money can buy--not unreasonable to want that---why wouldn't I want the youngest blood for my hip replacement from the blood bank for my surgery? The situation could get to that point where patients demand the best--again, not unreasonable---but if surgeries and hospitals begin to use the best blood saving practices out there--the likelihood of the situations will be diminished. Go to sites like Society for Advancement of Blood Management (SABM).

For the immediate question for cardiac surgery, the 'freshest' blood is their own with cell salvage, and most of your hospitals doing cardiac surgeries already have perfusion teams using cell savers. Meticulous hemostasis in surgery, using latest techniques and technology, cell salvage, etc, are all part of blood conservation.

I know I am rambling now, but it was only a matter of time when yet something else will impact the blood supply. There are a handful of forward thinking formal blood conservation programs in hopsitals that do transplants and heart surgeries with little or no allogenic blood. We should all be thinking in that direction.

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I met with our heart surgeons last Thursday and they have already jumped on the bandwagon. They don't care about supply, they don't care about any other patients, they don't care that we don't draw donors and are held captive by our blood supplier. They want blood less than 14 days old (actually they really want < 10 days) now and nothing else will be acceptable.

We'll do the best we can but that's all I promised.

:bonk:

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Our cardiac surgeons are going to look at the data (both from the journal and in-house) before proposing any changes. We seldom have "old blood" on the shelves but trying to maintain an exclusive inventory of <14 day old blood for cardiac patients is not logistically feasible. The big question we have is "young blood" for how many units? Is it best to "top off" at the end of the procedure with fresher units or do you need them for the whole procedure? If you give someone 20 units, only the last 5 (approx) will be in circulation during recovery and the rest will be on the floor.

Luckily, so far at least, our cardiac surgeons are being cautious.

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I am currently working on an audit for age of blood transfused for cardiac patients. 99% of cases have had blood less than 14 days. We go through supply so quickly, that it should be no problem to tweak the parameters and offer < 10 days. I also agree that cell saver and proper utilization practices are best.

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We don't do heart surgery, but I wonder if those that do would find AB+ and B+ patients much more likely to be given older blood and whether that will further impact the supplies. Then do you cross blood types for the fresher blood or is that a bigger risk (according to other posts on this site)?

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  • 3 weeks later...

Although publication in the NEJM gives this article the veneer of credibility, there are a number of problems with this study. First, it is a retrospective study, so it does not have the power that a prospective randomized controlled trial would have (despite the authors' attempt to argue that their retrospective data was "prospectively" by clinicians carrying out patient care. Although the authors argue that the populations were matched, they simply were not. Here are the differences between the populations that by the authors own work are statistically significant:

Statistically Significant Differences in the New Blood vs. Old Blood Populations

  • Blood group (# of units/total # of units - %)
    • 53.1% of new blood units were type O, only 31.1% of old blood were type O
    • 56% of old blood were type A, 37.9% new blood type A
  • Blood group (# of patients/total # of patients - %)
    • 50.9% new blood patients type O, only 30.4 percent old blood type O
    • 49.4 % old blood type A, 34.7% new blood type A
  • Higher rate of abnormal left ventricular function in the old blood group (63.1 vs 57.9%
  • Higher rate of mitral regurgitation for old blood (67.3 vs. 64.1%)
  • Peripheral vascular disease higher in old blood patients (58.5 vs. 54.4%)
  • Leukocyte reduction: significantly higher number of old blood patients receiving both leukoreduced and nonleukoreduced products (11.4 vs. 3.9)
  • Larger body surface area in older blood patients
#'s 3, 4 and 5 indicate a higher risk population than the "new blood" folks. The authors talk about ventilator time, but have made no adjustment for pre-existing lung function - these are elderly people - want to bet how many of those folks with peripheral vascular disease were/are smokers with less than optimal lung function?

Take a look at Figure 1A. This is where "demonstrate" the two populations are the same with regard to # of units transfused. The scale on the Y axis is 0-30. Now look at figure 3 - the Kaplan Meier curve they use to show their "significant difference" between old and new blood folks. Looks like a big difference, right? Until you check out the scale, where the entire graph is a 15% spread (from 85-100%). So they've magnified a really small difference to make it seem big. Oh, and if you pull that same little trick on figure 1a, it shows the same "huge difference" in the two populations as they are claiming for fig 3.

NEJM did a big disservice in printing this article in this form. The most this article does is support the need for a randomized controlled prospective trial. We are all aware the storage lesion exists, but none of us know its true impact on patient outcome in cardiac patients or any other.

That said, it unfortunately was well publicized on a slow news day. "Old Blood Can Kill You" in our local rag - it almost made me bleed into my brain. Although some of you are struggling with your surgeons and clinicians, my greatest concern is what we will be hearing from patients and their families every time we transfuse them and they question how old the blood is. And should there be a bad outcome for any reason, well - welcome to litigation land, because surely it was the "bad old blood" that killed the 85 year-old 3 pack a day smoker with CHF, diabetes and metastatic cancer, right?

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Would a randomized 'controlled' prospective clinical study be feasible, or even allowed by an IRB or the Office of Human Research Protections?

In reality, the study would simply be massive in order to represent enough clinical patient types, patient age (and other socio-economical) demographics, and stages of blood storage age (perhaps by week, number 1 through 6), among other dependent and independent variables, so proper conclusions could be drawn. My expertise isn't in study design, but I know if you do this study properly, it would be exquisitely expensive in time and money - not to mention the patient approvals - would you sign for yourself or your wife, son, daughter to possibly be the test subject who receives several units of 6 week old blood? I'm not being coy, maybe you would, but lack of participation would dampen the mood of a study very fast. Think about the analogy of participating in a 'taste test study' to determine the proper expiration date of milk. Most people wouldn't sign up to blindly taste milk that could be 2 days old, or perhaps 6 weeks old! Yuck......(it's just an analogy). The science behind expired milk and expired blood isn't the same, but it is quite plausible the average customer views them the same (they are both perishable).

Someone mentioned to me the other day the NIH National Heart, Lung, and Blood Institute is considering a grant for a study along these lines.

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Rich, I understand your point about the difficulties involved in performing a truly blinded randomized controlled trial to fully investigate this issue. My point is you have to look at the article for what it is - a retrospective study. It does not offer the strength of RCT, so one must be cautious about making decisions relying entirely on that type of study. What they are suggesting their study supports may, in fact, be true. Again, we all accept the presence of the red cell storage lesion, we're just not certain of its clinical significance at any given time. This study involved only cardiac patients, and may or may not be generalizable to that patient subset. But others have already reported clinicians other than cardiac surgeons who are asking for "new" blood for their patients. This study has a number of flaws, and correcting for those may still imply that for this group of patients "fresher" blood is better. But you have to balance all of it - limited power of a retrospective study, patient population-matching flaws, the statistically significant but small difference in the two populations, etc before allowing it to drive policy. Simply put, this study cannot stand on its own, and if people are making decisions based solely on this study I believe that is a mistake. Oh - just two things I forgot to point out on the other post - the old blood population actually received more blood than the new, and there are a number of studies supporting that "restrictive" vs. "liberal " transfusion policy provides better outcome in these patients. The second thing is that to gather data for mortality they used the social security death index. This provides only the date of death and the location (city and state). It does not indicate in any way cause or manner of death. It could be car accident, overdose (accidental or otherwise),etc. etc. Yet they still counted it as if it was due to having received old blood. Just one other thing you need to take into account when considering the results and conclusions of this study.

The post that reminded us conservation and rational transfusion practice are key is spot-on

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We do cardiac operations on adults, children and do ECMO. None of these populations get special treatment as far as the age of red cell components used. I would strongly oppose any change in this policy. The storage lesion is real, but thus far I think it is far from sorted out which patients if any should be given preferential treatment. As far as cardiac surgeons demanding/dictating transfusion policies, I would insist this go through medical executive AND ethics first before any changes are made. This area is ripe for abuse. We must stick to our guns and do what is best for all our patients.

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  • 2 months later...

At our center, we have standing orders with our hospitals for children receiving ecmo - blood must be 3 days old or less. For the rest of our customers - we have an unwritten FIFO understanding unless the physician/hospital specifically requests particular outdates.

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  • 3 weeks later...

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