For the first time, scientists have used therapeutic suspended animation to purposefully induce hypothermia and slow organ functions in patients with traumatic injuries, such as gunshot and stab wounds. The procedure, called emergency preservation and resuscitation (EPR), prolongs the amount of time that surgeons have to operate on a patient by up to two hours, reports Helen Thomson for New Scientist. At least one patient was put into suspended animation for surgery, but the nature of their injuries and whether they survived have not been announced. The clinical trial is still ongoing.
When a person sustains an acute trauma injury, surgeons typically have mere minutes to stitch up the wound before the victim suffers from severe oxygen or blood loss. Patients who lose more than half their blood often experience cardiac arrest and typically have about a five percent chance of survival, Thomson reports. Some wounds that might otherwise be easily tended can’t be patched up before a patient dies from bleeding out.
In an EPR procedure, surgeons pump ice-cold saline into the aorta (the main artery exiting the heart) at a rate of at least a gallon per minute. Once the body temperature has lowered to 50 to 60 degrees Fahrenheit, blood circulation and brain activity slows dramatically, giving the surgical team extra time to operate. After the wounds are stitched, surgeons pump blood back into the patient using a heart-lung bypass machine, increasing the temperature incrementally until their body is warm enough to circulate blood independently.
At a New York Academy of Sciences symposium on November 18, Samuel Tisherman, a professor of surgery at the University of Maryland School of Medicine, updated the medical community on his research team’s progress with EPR. Tisherman leads an EPR trial at the university’s Shock Trauma Center in Baltimore.
“This is cutting-edge science, and if it turns out to be something, it could have a massive impact on the way we treat people,” says Marko Bukur, a trauma surgeon at New York University’s Bellevue Hospital Center who is not affiliated with the trial.
In a 2017 article in the Journal of Trauma and Acute Care Surgery, Tisherman and his team reported that EPR was effective on large animals. Pigs were successfully cooled, operated on and resuscitated—and sustained brain function afterward.
But taking a carefully planned lab experiment to a trauma care unit presents serious ethical considerations.
The trial is set to include ten patients who will undergo EPR and ten who receive standard care. Eligibility requirements limit who can be a trial participant. For example, patients must not display signs of spinal or brain damage, and they must have a pulse within five minutes of entering the EPR process. The trauma center must also be outfitted to accept eligible patients when they come. Having a readily available bypass machine and perfusionist who is able to run it is expensive, Bukur says.
“Just the fact that they got one patient successfully enrolled and got them on bypass is pretty remarkable,” Bukur says. “But I don’t think we should say it’s a success or a failure based on one patient alone.”
Intertwined with that is the medical community’s long history of using disadvantaged communities for experimental technology. More than 90 percent of gunshot victims in Baltimore are men and of those, 90 percent are black men, most under the age of 30, according to the Baltimore Sun. Because of the demographics in neighborhoods near the Shock Trauma Center, it is “a virtual certainty” that participants in the experimental trial will be “black, low-income, and male,” as Nicola Twilley reported for the New Yorker in 2016.
“The news articles present the surgery as therapy for patients, but it is not. It is research with subjects and the focus is not on benefitting the subjects but rather putative future patients,” explains Harriet Washington, a bioethicist at Columbia University, in an email to Smithsonian magazine. “This deception embodies the ‘therapeutic illusion’ in which subjects are led to believe that they are the beneficiaries of cutting-edge medical science when in reality that are being used to serve the needs of others.”
Among the many complications of the study are the unknown effects of suspended animation on long-term health. Our brains usually only function for about five minutes without oxygen, according to New Scientist. If the brain and the rest of the body are chilled, however, biochemical reactions are slowed, and the body can go for longer periods of time without oxygen.
Still, oxygen deprivation may pose long-term damage to the brain as well as other vital organs. As the body warms again and blood is restored, chemical reactions with the oxygen can damage tissues. Serious cases can result in multi-organ failure, especially if a major tissue area is affected and the patient is dependent on a bypass machine for a long time. Tisherman tells New Scientist that his team is considering a “cocktail of drugs” that may minimize reperfusion injuries and extend the length of time a patient can be suspended.
The trial is expected to be completed next year, and the results could determine whether putting badly injured patients into suspended animation before surgery becomes a widespread practice at hospital trauma centers around the country.
“We felt it was time to take it to our patients,” Tisherman tells New Scientist. “Now we are doing it, and we are learning a lot as we move forward with the trial. Once we can prove it works here, we can expand the utility of this technique to help patients survive that otherwise would not.”
Editor’s Note, December 12, 2019: This story has been updated to include new quotes from Harriet Washington.