At a hospital in Pittsburgh, surgeons are now allowed to place patients into a state of suspended animation. If a patient arrives with a traumatic injury, and attempts to restart their heart have failed — if they’re on the doorstep of death — they will have their blood replaced with a cold saline solution, which stops almost all cellular activity. At this point, the patient is clinically dead — but if the doctors can fix the injury within a few hours, they can be returned to life from suspended animation by replacing the saline with blood. Or at least, that’s the theory. The technique of suspended animation (or “emergency preservation and resuscitation” as non-sci-fi doctors prefer to call it) was first trialed on pigs in 2002. Hasan Alam, working with his colleagues at the University of Michigan Hospital, drugged up a pig, created a massive hemorrhage to simulate the effect of a massive gunshot wound, and then replaced its blood with a cold saline solution, cooling the pig’s cells to just 10 Celsius (50F). After the injury was treated, the pig was gradually warmed back up by replacing the saline 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. Now, it’s time to try it out on humans.