Chilling study pushes medical boundaries
PITTSBURGH — Trauma patients arriving at an emergency room here after a gunshot or knife wound may find themselves enrolled in a startling medical experiment.
Surgeons will drain their blood and replace it with freezing salt water. Without heartbeat and brain activity, the patients will be clinically dead.
And then the surgeons will try to save their lives.
Researchers at the University of Pittsburgh Medical Center have begun a clinical trial that pushes the boundaries of conventional surgery — and, some say, medical ethics.
By inducing hypothermia and slowing metabolism in dying patients, doctors hope to buy valuable time in which to mend the victims’ wounds.
But scientists have never tried anything like this in humans, and the unconscious patients will not be able to consent to the procedure. Indeed, the medical center has been providing free bracelets to be worn by skittish citizens here who do not want to participate should they somehow wind up in the ER.
“This is ‘Star Wars’ stuff,” said Dr. Thomas M. Scalea, a trauma specialist at the University of Maryland. “If you told people we would be doing this a few years ago, they’d tell you to stop smoking whatever you’re smoking, because you’ve clearly lost your mind.”
Submerged in a frozen lake or stowed away in the wheel well of a jumbo jet at 38,000 feet, people can survive for hours with little or no oxygen if their bodies are kept cold. In the 1960s, surgeons in Siberia began putting babies in snow banks before heart surgery to improve their chances of survival.
Patients are routinely cooled before surgical procedures that involve stopping the heart. But so-called therapeutic hypothermia has never been tried in patients when the injury has already occurred, and until now doctors have never tried to replace a patient’s blood entirely with cold salt water.
In their trial, funded by the Department of Defense, doctors at the University of Pittsburgh Medical Center will be performing the procedure only on patients who arrive at the ER with “catastrophic penetrating trauma” and who have lost so much blood that they have gone into cardiac arrest.
At normal body temperatures, surgeons typically have less than five minutes to restore blood flow before brain damage occurs.
“In these situations, less than one in 10 survive,” said Dr. Samuel A. Tisherman, the lead researcher of the study. “We want to give people better odds.”
Tisherman and his team will insert a tube called a cannula into the patient’s aorta, flushing the circulatory system with a cold saline solution until body temperature falls to 50 degrees Fahrenheit. As the patient enters a sort of suspended animation, without vital signs, the surgeons will have perhaps one hour to repair the injuries before brain damage occurs.
After the operation, the team will use a heart-lung bypass machine with a heat exchanger to return blood to the patient. The blood will warm the body gradually, which should circumvent injuries that can happen when tissue is suddenly subjected to oxygen after a period of deprivation.
If the procedure works, the patient’s heart should resume beating when body temperature reaches 85 to 90 degrees. But regaining consciousness may take several hours or even days.
Tisherman and his colleagues plan to try the technique on 10 subjects, then review the data, consider changes in their approach, and enroll another 10. For every patient who has the operation, there will be a control subject for comparison.
The experiment officially began in April and the surgeons predict they will see about one qualifying patient a month.
It may take a couple of years to complete the study. Citing the preliminary nature of the research, Tisherman declined to say whether he and his colleagues had already operated on a patient.
Each time they do, they will be stepping into a scientific void. Ethicists say it’s reasonable to presume most people would want to undergo the experimental procedure when the alternative is almost certain death. But no one can be sure of the outcome.
“If this works, what they’ve done is suspended people when they are dead and then brought them back to life,” said Dr. Arthur L. Caplan, a medical ethicist at New York University. “There’s a grave risk that they won’t bring the person back to cognitive life but in a vegetative state.”
But researchers at a number of institutions say they have perfected the technique, known as Emergency Preservation and Resuscitation, or EPR, in experimental surgeries on hundreds of dogs and pigs over the last decade.
As many as 90 percent of the animals have survived in recent studies, most without discernible cognitive impairment — after the procedure, the dogs and pigs remembered old tricks and were able to learn new ones.
“From a scientific standpoint, we now know the nuts and bolts and that it works,” said Hasan B. Alam, chief of general surgery at the University of Michigan Medical Center, who has helped perfect the technique in pigs.
“It’s a little unsettling if you think of all the what ifs, but it’s the same every time you push into new frontiers,” he added. “You have to look at risk and balance it against benefits.”
Trauma accounts for more years of life lost than cancer and heart disease combined, and it is the leading cause of death in people up to age 44, according to the Centers for Disease Control and Prevention. Surgeons are eager for new techniques that would help better the odds in emergency situations. Black males are disproportionately victims of homicide, especially gun violence, and most of the patients likely to fit the study criteria in Pittsburgh are African-American males, according to officials at the medical center.
In order to obtain an exemption to federal informed consent rules, the hospital held two town hall meetings on the university campus, placed advertisements on buses, and made sure the news got in newspapers catering to minority readers.
Officials posted information about the study on a website, acutecareresearch.org, and conducted a phone survey in the neighborhoods most at risk for “involuntary enrollment” in the trial. Still, a taxi driver, grocery clerk and security guard — all African-American men approached at random — said they had never heard of the trial, though they work within a couple of miles of the hospital.
They also did not object. “I don’t have a problem with it, if it saves lives,” said Charles Miller, a 52-year-old security guard.
Just 14 people have so far requested “No EPR” bracelets, according to the medical center.
Nearly a half-dozen trauma hospitals may join the trial and begin testing the hypothermia procedure on dying patients, including the University of Maryland Medical Center in Baltimore.
Scalea, who will head the effort there, said he hopes to receive final regulatory approval by the end of the year.
He recalled a recent stabbing victim who died on his operating table.
“He might have lived if we could have cooled him down,” Scalea said.