Doctors have placed humans in suspended animation for the first time, as part of a trial in the US that aims to make it possible to fix traumatic injuries that would otherwise cause death.
Samuel Tisherman, at the University of Maryland School of Medicine, told New Scientist that his team of medics had placed at least one patient in suspended animation, calling it “a little surreal” when they first did it. He wouldn’t reveal how many people had survived as a result.
The technique, officially called emergency preservation and resuscitation (EPR), is being carried out on people who arrive at the University of Maryland Medical Centre in Baltimore with an acute trauma – such as a gunshot or stab wound – and have had a cardiac arrest. Their heart will have stopped beating and they will have lost more than half their blood. There are only minutes to operate, with a less than 5 per cent chance that they would normally survive.
EPR involves rapidly cooling a person to around 10 to 15°C by replacing all of their blood with ice-cold saline. The patient’s brain activity almost completely stops. They are then disconnected from the cooling system and their body – which would otherwise be classified as dead – is moved to the operating theatre.
A surgical team then has 2 hours to fix the person’s injuries before they are warmed up and their heart restarted. Tisherman says he hopes to be able to announce the full results of the trial by the end of 2020.
At normal body temperature – about 37°C – our cells need a constant supply of oxygen to produce energy. When our heart stops beating, blood no longer carries oxygen to cells. Without oxygen, our brain can only survive for about 5 minutes before irreversible damage occurs. However, lowering the temperature of the body and brain slows or stops all the chemical reactions in our cells, which need less oxygen as a consequence.
Tisherman’s plan for the trial was that 10 people who receive EPR will be compared with 10 people who would have been eligible for the treatment but for the fact that the correct team wasn’t in the hospital at the time of admittance.