In sci-fi films like "Avatar," the futuristic notion of suspended animation is often portrayed by turning humans into living icicles.
But in reality, sustaining someone in a state between life and death hasn't been possible. Until now.
In an effort to save lives, surgeons at the University of Pittsburgh Medical Center will soon attempt the scenario for a select few critically injured patients, cooling their bodies down until there are no signs of brain activity nor pulse. The technique gives surgeons more time to repair otherwise fatal injuries before returning the patients' bodies to a normal temperature—bringing them, so to speak, "back to life."
While sci-fi writers have their own term for the phenomenon, David King, a surgeon at Massachusetts General Hospital who helped develop the groundbreaking method, prefers the term “emergency preservation.”
“We're not stopping all internal body processes, but we're slowing them down dramatically," King says.
Technically, the patients will still be alive, though just barely.
Despite the countless medical advances of our time, blood loss remains one of the biggest challenges doctors face, responsible for 40 percent of hospital deaths that occur in any given day, according to the nonprofit National Trauma Institute. Victims of gunshot wounds, stabbings and automobile accidents die most often not from the severity of their injuries, but from rapid blood loss; likewise, the leading cause of death for soldiers in combat is massive blood loss within the first five to 20 minutes of injury.
Beginning this month, 10 trauma patients will receive the experimental procedure. Medics and first responders will apply conventional methods to try to restart the hearts of all patients that go into cardiac arrest as a result of excessive bleeding. It's only when these efforts fail that surgeons will intervene to test the new technique, swapping out the patient's blood with a cold saline solution (held at 50 degrees Fahrenheit) through a catheter tube inserted into the aorta, the heart's main artery.
This stops blood flow, and thus, bleeding, while keeping organs running.
"Everything [cellular metabolism] slows down so much that the existing amount of substrate is enough to support the ongoing low metabolic rate for some period," King says.
The aim, initially, is to chill and preserve the heart and brain as the patient's body temperature is gradually brought down to the same level, a process that takes about 15 to 20 minutes. An hour later, once injuries are fixed, surgeons pump blood back into the body, restart the heart and allow the body's temperature to rise back to a normal level, which usually takes about two hours.
In a sense, "emergency preservation" is a kind of medically-induced hibernation. Ground squirrels, for instance, naturally drop their body temperatures to near below freezing to slow their metabolism during the winter months. Circulating saline solution through a human body achieves a similar effect: lowering body temperature causes cellular processes to scale back to a state in which organs can, for a short amount of time, subsist on their own.
The results of the experimental procedure will be compared to the outcomes of 10 patients with similar conditions who received only traditional treatments. If the outcomes are encouraging, more patients will receive the treatment.
The trial is being conducted under a federal legal exemption that allows for experimental procedures without consent in the case of life-threatening emergencies. Nearby residents, however, can opt out by wearing a special bracelet available through the hospital; the researchers have also held town hall discussions to spread public awareness of the study.
The procedure, developed and tested successfully as far back as the year 2002 through experiments using pigs, has a 90 percent success rate and hasn't turned up any noticeable signs of neurological damage. But this marks the first time the procedure will be tried on humans.
"Right now, we don't have any therapies for traumatic arrest," King says. "We understand there might be some side effects, but it's tolerable if the alternative is death."
But the extent of such damage, along with any resulting long-term health consequences, remains unclear.
“We conducted cognitive assessments in animals and they did well, but human brains operate differently." King says. "So it's an unreasonable expectation that there won't be any brain damage and the short answer is we don't know what those would be."
King says patients' health conditions can also further complicate the degree with which the procedure can be effective.
"Labs animals are healthy, disease-free," King point out. "But in the real world, when you have a 62-year-old man hit by a car, has heart disease, diabetes and whatnot, has to have this procedure, I wouldn't expect a similar outcome."
While “cells still suffer a bit" with the procedure, "it's a lot less than they would than when you were warm.”
And taking the risk could mean the difference between dying and holding on to life.