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JCruz

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JCruz last won the day on April 30 2008

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About JCruz

  • Birthday 11/19/1968

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  1. Frozen products (plasma, frozen rare red cells) collected prior to Zika testing will still be around. The FP/PF24 will cycle out after a year as products outdate, but there will still be those frozen rare red cells around. That doesn't mean you have to maintain the process as they were collected prior to the testing and are acceptable for distribution, but something you might want to keep in mind at least until all the plasma is cycled out if you have the process in place.
  2. 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
  3. 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 O56% of old blood were type A, 37.9% new blood type ABlood group (# of patients/total # of patients - %)50.9% new blood patients type O, only 30.4 percent old blood type O49.4 % old blood type A, 34.7% new blood type AHigher 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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