Sending a manned mission to Mars poses some of the greatest technological challenges humanity has ever faced: a spacecraft must be maintained over tens of millions of miles of freezing emptiness, sustaining astronauts for years of isolation.
Then, if one of them becomes ill, you have to do first aid standing on your head. Proving that space scientists leave nothing to chance, astronauts now have the answer to the burning question of how to do cardiopulmonary resuscitation in zero gravity.
CPR is the standard treatment for someone whose heart has stopped. However, the vigorous chest compressions needed to restart it are not possible when weightless, as the thrusts would simply propel the first aider through the air. “There is no documented case of a cardiac arrest in space, but the question is not if but a matter of when,” said Jochen Hinkelbein of the University Hospital of Cologne, president of the German Society for Aerospace Medicine. “In the future more and more long-term missions are planned, for example flying to Mars.”
Several tests have attempted to find CPR techniques that work in zero-gravity simulators, ranging from first aiders strapping themselves to the floor to them giving the patient a Heimlich-like reverse bear hug. Professor Hinkelbein will tell the Neuroanaesthesia conference in Geneva today that there is a clear winner. A handstand method, where the first aider braces their feet against the ceiling and pins the patient against the floor, succeeded in moving the chest the required 5cm and achieving 100 compressions a minute.
“Astronauts should know how to do it, they should use the best available [method] and that’s the handstand — but only if you have walls two metres apart,” said Professor Hinkelbein.
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In larger spaces, where they cannot brace against walls, astronauts must revert to what is known as the Evetts-Russomano technique. “This is where the patient floats freely and the other person sits on their chest.” This method does not give as deep a compression, but does give a higher number per minute.
Professor Hinkelbein admits that they are yet to solve the problem of what to do when lifesaving treatment fails. “If you’re not successful and you have a body you can store him or freeze him. The easiest thing to do would be to put him into the waste module and drop him — but that’s an ethical problem not a technical one.”