Suspended animation is a staple of science fiction. Need to take a 200 year trip to another star system? Go to sleep in some sort of high-tech coccoon and wake up at your destination. We saw it in Star Trek, 2001, and many other places. Doctors at the University of Maryland have reprtedly put at least one patient in suspended animation, and it isn’t to send them to outer space. The paper (behind a paywall, of course) is available if you have the medical background to wade through it. There’s also a patent that describes the procedure.
Trauma surgeons are frustrated because they often see patients who have been in an accident or have been shot or stabbed that they could save if they only had the time. A patient arriving at an ER with over half their blood lost and their heart stopped have a less than 5% chance of leaving the ER without a toe tag. By placing the patient in suspended animation, doctors can gain up to two hours to work on injuries that previously had to be repaired in mere minutes.
Normally once your heart stops, your brain will irreversibly damage in about 5 minutes due to lack of oxygen. The heart meanwhile can survive for about 20 minutes. Doctors are replacing all of a patient’s blood with ice cold saline. This causes brain activity to stop and slows or stops chemical reactions that normally cause damage. Technically, the patient is dead.
Surgeons then have about two hours to do their thing before warming up the patient and restarting his or her heart. The FDA approved the study which plans to put up to ten people in suspended animation. The patients won’t have to consent because they have fatal injuries with no alternative treatment. However, the team did place ads in local newspapers with a web site that allows people to opt out if they don’t want the procedure in the future.
The thawing out remains problematic. As the temperature rises, chemical reactions can cause cellular damage. It appears that the longer you are dead, the worse this damage can be. Doctors hope to find a drug cocktail to help prevent these reperfusion injuries. The goal temperature is 10C and upon rewarming, they bring the patient up to 34C, about 3 degrees low and wait for the body to recover over a 12 hour period in most cases.
Working on pigs, they have been able to keep them cold for 3 hours and revive them. The report isn’t clear on exactly how many of the patients have been frozen and successfully thawed out, nor does it share how well the thawed out patients recovered. Presumably, that will be in the paper they publish next year.
We don’t suggest trying this at home, but it does lead to some interesting questions about your brain and conciousness in general. A few hours won’t get Kahn to Ceti Alpha V, but it could be a start of developing technology that could enable long space flight.