For the first time, scientists in the US will test a groundbreaking emergency technique in which knife-wound or gunshot victims will be cooled down and placed in suspended animation - a state where people are not alive but not yet dead.
At a hospital in Pittsburgh, Pennsylvania, doctors will try to save the lives of 10 patients who will be kept between life and death in the first suspended animation trials on humans.
The technique, if successful, could be used in medical emergencies giving doctors more time to treat patients with traumatic injury (gunshot, stabbing, etc).
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The procedure involves replacing all of a patient's blood with a cold saline solution, which rapidly cools the body and stops almost all cellular activity.
"We are suspending life, but we don't like to call it suspended animation because it sounds like science fiction," said Samuel Tisherman, a surgeon at the UPMC Presbyterian Hospital, who is leading the trial.
"So we call it emergency preservation and resuscitation," he said.
The technique of suspended animation was first trialled on pigs in 2002 by Hasan Alam, working with his colleagues at the University of Michigan Hospital, 'New Scientist' reported.
The animals were sedated and a massive haemorrhage induced, to mimic the effect of multiple gunshot wounds. Their blood was drained and replaced by either a cold potassium or saline solution, rapidly cooling the body to around 10 Degress Celsius.
After the injuries were treated, the animals were gradually warmed up as the solution was replaced with blood.
Usually the pig's heart started beating on its own, and despite the pig being dead for a few hours, there was no physical or cognitive impairment.
"After we did those experiments, the definition of 'dead' changed," said surgeon Peter Rhee at the University of Arizona in Tucson, who helped develop the technique.
"Every day at work I declare people dead. They have no signs of life, no heartbeat, no brain activity. I sign a piece of paper knowing in my heart that they are not actually dead. I could, right then and there, suspend them. But I have to put them in a body bag. It's frustrating to know there's a solution," Rhee said.
The technique will be tested on 10 people, and the outcome compared with another 10 who were not treated this way because the team was not on hand.
The technique will be refined then tested on another 10, said Tisherman, until there are enough results to analyse.