Tuesday, 28 September 2010

Back from the Dead

This is about Horizon from last night, it had some incredible stuff, definitely worth an iPlayer visit if you like what you read.

Humans are very intricate machines, but that means we're also very sensitive to change. In terms of temperature, we vary very little from our standard 37 degrees celsius. If we dropped 1 degree it would be painful, about four or five and you'd feel pretty woozy before passing out. Stay there, and you'd die. Which makes it all the more strange that a woman whose core temperature fell to 14 degrees, a drop of 23, managed to survive for around 2 hours with no heart beat. She had no pumping blood, no breathing, not even any signs of brain activity. By any conventional measure she was dead. But a few months later she was alive, exactly as healthy as she was before.

Now is it just me in my little nerdy medical school bubble that thinks that's pretty cool?

It was precisely because she was so much colder than she should have been that she survived. Without blood the brain would usually starve and die irreversibly, but she was so cold that the brain stopped functioning before it had a chance to starve. It essentially went into hibernation, ready to be warmed back up again. As soon as she started getting heat back, her heart started beating and her brain started again. She wasn't back to normal in a day, or even a week, but the fact she recovered at all is incredible enough.

That might have just been sheer luck, but now hospitals can use the same principle to operate on people who would otherwise have been consigned to death. They can stop the blood flow without starving the organs, something you can't do any other way.

With the patient on the operating table they cool them down to around 18 degrees by taking out the warm blood, passing it through a freezing heart lung machine, and putting it back in. Then, slightly less high tech, they surround them with ice packs. They can then shut down the heart lung machine, have no pumping blood getting in the way, but rather than the patient dying in a matter of seconds, they have about an hour in which to work. Obviously, they can't push the window much further because no-one is going to risk a patient just to prove a point.

Then there's the even more exciting use for the idea. Most young deaths are caused by trauma, and in trauma cases (hit by a car, stabbings etc.) there's a very short amount of time to help someone before its too late. But what if you could give someone an extra hour, how much more help could you get then?

When you get to A&E for a very serious case and you're heart isn't beating, one of the things they may well do is open up your chest to massage your heart. Some doctors figured, whilst we're in there, why not infuse the blood with freezing cold saline to drop their body temperature rapidly. If they could preserve the brain for long enough, they'd have more chance to repair the damage. In an environment where every second counts, having an extra hour would be worth more than words could say. Millions of people could be saved.

Then just as if we hadn't had enough, there was what for me showed the future of medicine. People always say its genetics and I'm sure that will transform it, but this could be huge. Its just an idea at the moment, but when its fleshed out it could be incredible.

A researcher showed that cells don't automatically die when starved, they die once they start getting oxygen again because they can no longer perform their old job. Once a cell becomes useless it essentially commits suicide. Now this works well in the human body, keeping us refreshed, but obviously if too many cells decide enough's enough at the same time then you're in trouble.

What this guy found is that a certain part of the cell, the mitochondria, controls the cell death, and it might be able to be interfered with. If you could stop the cell committing suicide, you could essentially put someone into limbo, giving you enough time to repair them. The exciting thing would be, if this could be given as some form of injection or infusion, you'd have no need to be in an operating room to be frozen. You could get to a stage where paramedics in the field could hit the pause button on you and whizz you back to the hospital without you dying a little more every second.

If you can stop cells dying, the possibilities for how you could use it in medicine are truly endless. Survival rates for all sorts of things would rocket immediately. Death wouldn't be inevitable in any situation. We're not even close to having it ready right now. But at least we know its a possibility, and one day we might make it.

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