Doctors Have Placed Humans on Brink of Death in State of Suspended Animation for First Time

Doctors in the U.S. say they have placed humans on the brink of death in a state of suspended animation for the first time.

The technique—known as emergency preservation and resuscitation (EPR)—is being trialled at the University of Maryland Medical Center in Baltimore on patients who arrive with injuries such as stab or gunshot wounds and have gone into cardiac arrest, as well as having lost more than half their blood, New Scientist reported.

Normally, patients in this condition only have a less than 5 percent chance of living and surgeons only have a window of few minutes to save them.

However, EPR could help to buy doctors some precious time. It involves replacing all of a patient's blood with an ice-cold saline solution which rapidly cools their body temperature down to between 50 and 59 degrees Fahrenheit.

This puts a pause on nearly all their brain activity and stops the heart. Patients are then taken to be operated on in this state of suspended animation before being warmed up again a maximum of two hours later.

When our bodies are operating at normal temperatures, the cells inside need a constant supply of oxygen to stay alive. This oxygen is supplied by the blood which is pumped around the body by the heart. So, if the heart stops, irreversible brain damage will occur within about five minutes because the brain is not being provided with the oxygen that it needs.

But the cells inside the bodies of patients who have been placed in suspended animation require much less oxygen to stay alive because the low temperatures have slowed down the chemical processes taking place within them. This means that patients can remain alive, even though their lack of heartbeat and brain activity would normally be enough to classify them as "dead."

The full results of the research likely won't be ready until the end of next year, but leader of the trial Samuel Tisherman, from the University of Maryland School of Medicine, discussed the team's progress at a New York Academy of Sciences symposium on Monday.

According to Tisherman, at least one person has been placed in suspended animation as part of the trial so far, although he didn't disclose how many people survived after undergoing EPR.

"We are learning a lot as we move forward with the trial," Tisherman told New Scientist. "Once we can prove it works here, we can expand the utility of this technique to help patients survive that otherwise would not."

"I want to make clear that we're not trying to send people off to Saturn," Tisherman said. "We're trying to buy ourselves more time to save lives."

It is important to note that there are inherent problems with placing people in suspended animation. The longer cells in the body go without oxygen, the more damage they suffer. Furthermore, the re-warming process itself can also cause damage to cells.

The team think that a mixture of drugs could be used to mitigate this cell damage, but Tisherman says that more research is needed to understand this process.

Ariane Lewis from NYU Langone Health, who is not involved in the trial, described the suspended animation research as significant while also noting that the project was still in its early stages.

"We have to see whether it works and then we can start to think about how and where we can use it," Lewis told New Scientist.

Normally, doctors conducting medical trials require the consent of patients to try out new treatments. But in this case, the U.S. Food and Drug Administration approved the trial without the need for patient consent on the basis that the injuries involved are likely to be fatal and no alternative treatments are available.

The team advertised the trial among the local community and have given people the option to opt out via the project's website.