When doctors are trying to stop someone from dying of catastrophic blood loss, what they really need is more time. Time to find the flow, time to clamp and suture without worrying about blood loss depriving the body of oxygen or about organ failure, brain damage or cardiac arrest. In Mosaic, as part of a comprehensive story on the science of human hibernation, science journalist Frank Swain writes about one way trauma surgeons are giving themselves more time to save a person's life—they are getting ready to start, essentially, shutting down the patient's body.
It's already accepted practice for surgeons to cool people down to temperatures as low as 59 Fahrenheit. At this point the heart will stop, giving the surgeons time to work. But this new, experimental technique, called “emergency preservation and resuscitation" and devised by University of Pittsburgh's Dr. Sam Tisherman, involves going even colder, says Swain, “chilling [patients] to such a degree that the entire body enters a kind of suspended animation.”
During this time, they will have no heartbeat, no breathing and no discernible brain activity. In fact, they’ll have no blood, either – it will be drained and replaced with ice-cold saline, the only way to cool a human fast enough to avoid tissues becoming damaged as they struggle to remain functioning. Tisherman calls this state “hypothermic preservation”.
This sounds a little like science fiction; it's real enough, though, that it's supported by the U.S. Army. Inducing something akin to human hibernation is by no means easy or straightforward, and the benefits are offset by considerable risk. Yet, Swain says that the technique already works for dogs, and will be tested on people as part of a clinical trial at the Massachusetts General Hospital in Boston.