Suspended animation has allowed many a sci-fi character to travel to a distant corner of space in a state of dormancy, only reanimating once they’ve arrived at their otherworldly destination. Now, the concept is being tested as a way to save the lives of acute trauma patients, with at least one person being placed in suspended animation in the US so far.
When a person suffers a severe trauma like a stab or gunshot wound, they can lose so much blood that their heart stops beating, which makes standard CPR futile. Instead, surgeons open the chest and attempt to reroute blood to the heart and brain, but this often fails to save lives.
“You’ve got someone who’s got an injury, it’s fixable, but you’ve not got time to fix it,” Professor Samuel Tisherman, of the University of Maryland School of Medicine, told an audience at the New York Academy of Sciences symposium on November 18.
So how do you buy more time? This is where the concept of suspended animation comes in, although as Tisherman pointed out during his lecture, doctors are trying to “get away from the sci-fi notion of suspended animation,” calling it emergency preservation and resuscitation (EPR) instead.
In a recent interview, Tisherman told Helen Thomson at New Scientist magazine that his team has tested out EPR on at least one person, describing it as “a little surreal”. However, he did not say how many people had survived.
EPR involves rapidly cooling the body down so that the brain is at a chilly 10-15°C (50-59°F), far below its usual 37°C (98°F). This is done by pumping the body full of very cold salty water.
“We came up with this idea that the fastest way we could cool the whole body, particularly the brain and the heart, was just to flush the body with cold fluid, and saline’s what we use,” Tisherman said at the symposium.
Being very cold slows bodily processes and chemical reactions right down, meaning that organs like the brain require much less oxygen than they would otherwise. Once in this cooled-down state, the patient can be taken to the operating room, where surgeons have up to two hours – rather than a matter of minutes – to get to work and repair the life-threatening damage. Once complete, the patient is resuscitated using a cardiopulmonary bypass, a machine that takes over the function of the heart and lungs.
The technique has proved successful on animals like pigs, so with approval from the FDA, Tisherman’s team is taking it to human subjects. Since people whose hearts have stopped due to acute trauma are unlikely to survive, consent by the patient is not required. However, the team printed ads in local newspapers telling readers how to opt-out of the trial if they so wished.
The plan is to test EPR on 10 patients, using a further 10 as controls. These controls will be patients who arrive at the hospital when Tisherman’s full team is not there, meaning that EPR can’t be carried out.
EPR does have its drawbacks; it is possible to suffer cell damage when the body is warmed up and blood flow is restored. Exactly why this happens isn’t completely clear, but certain medications might be able to counter the effects. The ultimate aim is for patients to survive without any significant neurological deficits.
“We certainly hope that this kind of approach, basically just trying to stop the clock, buy time, maybe with hypothermia, maybe with drugs… will allow us to save the trauma patients that are currently dying in front of us,” Tisherman told the symposium.
“Hopefully in the future we’re going to have patients survive that otherwise would not.”[H/T: New Scientist]