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Treating the Dead
FlyByPC writes "According to a NewsWeek article, oxygen deprivation doesn't kill patients as much as the resumption of oxygen does. This discovery could bring about new ways of resuscitating people whose hearts have stopped."
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the number of things that we, as humans, seem to learn about ourselves each day and week. Theoretically, this could save thousands of people if they figure it out, and would possibly change how we look at the actual moment of death. Might this also be helpful in cryogenics? or how many other branches of medicine? Could this make organ transplants more safe? Could it make heart surgery safer?
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It does not do any good to have a working body if I am still brain dead at the end of the process.
It might be useful so organs could be used for a transplant.
Yeah, reprofusion injury http://en.wikipedia.org/wiki/Reperfusion_injury.
I wrote about that >20 years ago, when I was writing for a biotechnology newsletter. After >20 years of research, they understand it much better today.
Every surgeon knows about reprofusion injury. You can go to Barnes & Noble and look it up in a surgery textbook.
I don't understand why Newsweek says it's new or that it wasn't known in 1993. I assume those doctors came up with some new detail in its treatment.
Yes, actually, they are good American names.
"I don't know, therefore Aliens" Wafflebox1
The article has a strange focus on the '5-minute window' of oxygen deprivation to heart muscle. Heart muscle can survive and recover far beyond that 5 minutes. Clot busting drugs can be give hours after a coronary artery becomes occluded, restoring blood supply to heart cells that have been without oxygen that whole time.
It's the brain that's exquisitely sensitive to oxygen deprivation. That 5-minute window refers to irreversible brain damage that begins to occur after ischemia, not heart damage. It's also well known that brain tissue releases toxic metabolites after oxygen deprivation doing damage above and beyond what the lack of oxygen itself did. There are a number of therapies aimed at reversing or blocking this phenomenon, but none have been successful yet.
The intervention that has been shown to be most effective in changing survival outcome once someone's heart has stopped beating is good quality CPR as soon as possible. Most of these other innovations like cooling have only a minimal effect changing a dismal outcome to a not-quite-as-dismal-but-still-pretty-dismal outcome. Most of these intra and post resuscitative interventions only succeed in allowing a patient to linger in the ICU for a few extra days before finally dying.
Actually the primary reasoning for the change was largely to keep it simple. This means there is ONE ratio to remember for all lay-rescuer (single person) CPR for anyone that is not an infant.
There is not a single 'ideal' compression to ventilation ratio. We know that for garden variety cardiac arrest due to V-Fib, ventilation in the first minute or so is probably almost meaningless. We also know that for hypoxic arrests (like a drowning) that ventilation is far more important. We also know that VFib makes up a greater percent of adult arrests and hypoxic arrests are more common in kids (all of whom get the same ratio.) Moreover the AHA made this decision knowing that they didn't even know the ideal ratio for the single most common type of arrest in the community (from VFib.) The 30:2 ratio was a way of keeping it simple that is not perfect for every kind of arrest, but is a reasonable compromise to try to deliver at least a reasonably acceptable type of CPR to all victims of arrest.
That is a good thing for lay-rescuers, but the AHA understands that people who are more highly trained and knowledgeable will guide their actions based on that knowledge. For example, if my partner grabbed his chest and collapsed, I would run to the phone, call 911. Return to him, check for a pulse, and if he had none, start wailing on his chest like a crazed weasel on crack. I would not even consider breaking compressions to give a breath till at least minutes had passed - or more trained people arrived and ACLS could be initiated. If however, I pulled him out of a pool, I would check for breathing and if none, give two full rescue breaths. Then check for a pulse, if none, start CPR with probably about a 15-20:2 ratio. I would stop for a moment at 1 minute. If he had a pulse, I would continue breathing for him a full minute or two before I ran to the phone. If he had no pulse, I would give two last breaths and run for the phone.
Those are drastically different methods that I chose knowing that they would give him the best chance in either situation. But if you try to teach lay-rescuers that, you will get blank stares and some shitty-assed CPR. So it is better to make things as simple as possible and make them so at least everyone gets 'reasonable' CPR.
Nick