First human trials for “suspended animation” to start this month
Dr. Samuel Tisherman, a surgeon at UPMC Presbyterian, spoke with New Scientist earlier this year and said, “We are suspending life, but we don’t like to call it suspended animation because it sounds like science fiction. So we call it emergency preservation and resuscitation.”
The technique was first devised by Dr. Peter Rhee, of the University of Arizona in Tucson, and tested on pigs in 2000. The pigs were wounded to mimic multiple gunshot wounds. Their blood was then replaced with a cold saline solution to cool their bodies down, and their wounds were treated. All the pigs of the control group died, but the pigs that were put into suspension had a 90 percent survival rate once their bodies warmed up. The surviving pigs did not exhibit any physical or cognitive impairment.
Cooling the body is key to this new trial. Prior to brain or heart surgery, doctors will sometimes cool a patient’s body using ice packs and circulating the blood through an external cooling system. Doing so gives surgeons more time to perform surgery. Unfortunately, this process is not possible for victims of injuries resulting in extreme blood loss, such as a stabbing or gunshot wound. Such injuries only give doctors minutes to stop the bleeding and restart the heart. That’s where emergency preservation and resuscitation comes in.
The hospital is ready to start the trials; they’re just waiting for the right patients. These patients will have been victims of cardiac arrest after severe traumatic injury, likely resulting in an open chest cavity and massive loss of blood. Such an injury would normally only have a seven percent survival rate.
Similar to the pigs, the process starts with cooling the body and inducing hypothermia. The patient’s blood will be removed and replace with a cold saline solution to lower the body’s temperature to 10 degrees Celsius. This will slow down bodily functions. The lower the temperature, the less oxygen the body needs to function. The patient will then be taken to an operating room, and due to the preservation, the surgeons will have up to 2 hours to fix the injury. Once the operation is successful, the saline will be replaced with blood. The new blood will warm the body slowly. If the heart does not restart itself the patient will need to be resuscitated.
The trials will be done on 10 patients who meet the criteria. The results will be compared to another control group of 10 patients that will inevitably not be able undergo the process due to the unavailability of the surgical team. The first phase of the trial will be used to refine the technique, and the process will repeat until there is enough data to determine its effectiveness.
Approving the technique for the hospital has been a difficult ordeal. Neither the patient nor the family can give consent to the trial, as it will be in the event of a medical emergency. The US Food and Drug Administration considers the situation to be exempt from informed consent, as the injuries would likely prove to be too fatal, with no alternative treatment. The trial has been subject to a campaign of advertisements in newspapers and discussions with groups in the community to educate the populace. People are given the chance to opt out of the trial through an online website.
Tisherman hopes to apply emergency preservation and resuscitation to other medical conditions. For now, the technique only preserves life for a few hours. “We’re trying to save lives, not pack people off to Mars,” said Tisherman. “Can we go longer than a few hours with no blood flow? I don’t know. Maybe years from now someone will have figured out how to do it, but it will certainly take time.”
By Alfredo Dizon, eParisExtra