Suspended animation in humans successfully tried for the first time

By Dr. Ananya Mandal, MDNov 25 2019

Researchers from the University of Maryland School of Medicine, for the first time have put a patient in “suspended animation” successfully. Using this method, they lowered the body temperature of the human patient for the first time. This would help surgeons to prolong the time of surgery to correct traumatic injuries. The plan of their feat was published in the latest issue of the New Scientist last week.

Team of surgeons. Image Credit: Gpointstudio / Shutterstock

The trial has been named Emergency Preservation and Resuscitation (EPR) for Cardiac Arrest From Trauma (EPR-CAT) that started since 2010 works with the principle of lowering the body temperature and cooling the body when there is a severe traumatic injury such as a knife injury or a gunshot injury. These patients tend to lose a large amount of blood rapidly that causes cardiac arrest, explain the researchers. Usually the chances of survival are low. When the heart goes into an arrest, the surgeons have a few minutes to stop the bleeding and reverse the patient before there is a more permanent damage. This lowers the chances of survival to 2 to 5 percent say the researchers. Sometimes even if the patient survives, his per her brain may suffer from a permanent damage due to the cardiac arrest and loss of blood causing coma or paralysis etc. In this trial the team attempted to rapidly cool the body of the patient so that some extra time could be obtained while the surgeons can operate on the patient.

Main investigator of the trial Samuel Tisherman said that this “induced hypothermia” places the patient in a form of suspended animation while they can work. The temperatures are lowered by around 27 degrees Celsius to around 10 degrees Celsius (50 degrees Fahrenheit) using iced solution of saline. This puts all the processes of the body on hold and slows down metabolism. Overall the oxygen requirement of all the cells is also reduced substantially and this buys some time before lowered oxygen due to the blood loss can damage the organs.

Researchers have been working with this model of induced hypothermia for a while now. Human trials have never been conducted before however. The experiments had shown success with dogs and other large animals however. For the dogs, the team had pumped out all of the blood and their blood vessels were pumped up with cold saline solution. After three hours of remaining in such suspended state, the scientists had replaced the saline with blood again and managed to bring the dogs back from the dead with no brain damage or any other organ damage. In 2017 Tisherman and his colleagues published a paper in Journal of Trauma and Acute Care Surgery, that looked at the results of EPR on large animals. They tried their technique on pigs successfully at the time.

For this new trial on humans the researchers would be enrolling 20 patients at Shock Trauma Center in Baltimore. Of these 10 would be given EPR or the induced hypothermia therapy while 10 would be treated traditionally. This trial has a lot of ethical concerns. One of the most important concerns was the fact that severe trauma patients would not be able to provide consent to participate in the trial. The Food and Drugs Administration (FDA) approved of this study only if the patients did not have an alternate treatment available for them and also members of the family and community must agree to be part of the study.

Tisherman has presented the plan of the study at the New York Academy of Sciences this week and has revealed that they have successfully tried their process on one patient now. The results of the study are expected by December 2020 says the team. He called the process “surreal” at the New York Academy of Sciences symposium. He has not yet revealed the outcome of their procedure and if the patient they tried it on, was doing well. One of the greatest worries with this process is the possibility of damage to the cells after the patient has been warmed up.

Tisherman spoke on the study to New Scientist saying, “We felt it was time to take it to our patients. 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.” His talk was titled “suspended animation”. He said, “I want to make clear that we’re not trying to send people off to Saturn. We’re trying to buy ourselves more time to save lives.” This last statement was in context of the NASA trying to send people for interstellar travel while in hibernation mode.

Kevin Fong, a consultant anaesthetist at University College London hospital, who has worked with induced hypothermia before but is not involved in the present study said, “Emergency preservation and resuscitation is an attempt to protect a dying patient by dramatically dropping their body temperature and forcing their physiology into slow motion. It can take a situation in which there are mere seconds to save someone’s life and smear that out into many minutes.” He added, “The cardiothoracic surgeons have been doing something very similar for decades, but this is about moving that technique forward, into the emergency department or perhaps maybe even out into the field. In emergency medicine we’re always trying to blur the line between life and certain death, to create something that looks like hope where none previously existed. If EPR works, it’ll be a game-changer.” Marko Bukur, a trauma surgeon from New York University’s Bellevue Hospital Center, not involved in this study, also said, “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.”