Does CPR work in space?

How do you do CPR in space? Chris Smith asked space doctor Christina Mackaill...

Chris - So if someone has a heart attack or a cardiac arrest and you need to try and resuscitate them. Very difficult I would think when you’re weightless?

Christina - Yeah. So the problem with giving CPR in space the same way as we do on Earth is, of course, there's no gravity so you be floating around. You could technically restrain the astronaut needing CPR and the rescuer to the ground but that would take time and the longer you leave it before you start CPR, the chances of survival decrease quite dramatically.

So there's three sorts of ways to do on the space station which can be initiated immediately. The first one is called the handstand method and, as it sounds, the rescuer would put their feet on the ceiling of the space station and use their legs to push off it, and they push onto the person's chest who'd been lying on the ground.

The other one is called the reverse bearhug which, again, like the name suggests you would go behind the person needing CPR and given sort of a hug and push in on their chest. And the last one's called the Evetts-Russomano method which involves the rescuer putting their left leg over the person’s right shoulder and then their right leg under the person's left arm so sort of wrapped around their back...

Chris - Like a scissor manoeuvre?

Christina - Yeah. And then giving them chest compressions from the front. So in simulated studies during parabolic flights which the plane - the vomit comet - goes up and recreates microgravity and simulations in air.

Chris - Have you been on it?

Christina - No. I'd love to but...

Chris - I'm not sure - I would probably throw up though. I think most  people do, don't they?

Christina - The vomit comet, yeah. I think that's why they call it.

Chris - Even people who are quite resilient still throw up.

Christina - So in these studies the handstand method has been proven to give the best quality compressions. However, the problem is if your small like I am, I probably couldn't do that because I won't be able to reach the ceiling. So in that case the next best one is the Evetts-Russomano method which only had slightly lower quality chest compressions, and the advantage of that as well if your in a position to give ventilation.

Chris - Lee?

Lee - Couldn't they just make a kind of compression chest you know like a corset that just goes on and off, on and off?

Chris - Would that work?

Christina - Yeah. I've been asked that because sometimes in some scenarios on Earth we have to use those if CPR is on going for a long time because the problem with human CPR is that you can fatigue and that can affect the quality of chest compressions.

But at the same time, we still need to know how to do it in a scenario where, again, it might delay time putting this machine on or it might not be available. These things are heavy and expensive as well; we need to bare that in mind when we're travelling to space or on Mars or things like that. The reverse bearhug method isn't great out of all of them. It was the most fatiguing and, as I said, once you get tired the quality gets a bit worse.

Chris - Having had to do a lot of CPR on people in my job, my medical job, it's knackering! And it's knackering when you're on the ground not fighting against all the exigencies of weightlessness. I should think it's probably extremely taxing trying to do that in space?

Christina - Absolutely. So I did a study a couple of years ago and it wasn’t zero gravity, but were simulating Mars and it was exhausting because you weigh less and as you know to give CPR here we rely a lot on our body weight, but because you weigh less you've not got enough strength essentially. So yeah, it's difficult.