PITTSBURGH : Patients with trauma arriving at an emergency room 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 saltwater. Without heartbeat and brain activity, the patients will be clinically dead. And then the surgeons will try to save their lives, the New York times reported.

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.

“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 in which a penetrative wound has already occurred, and until now doctors have never tried to replace a patient’s blood entirely with cold saltwater.

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.”

The experiment officially began in April and the surgeons predict they will see about one qualifying patient a month.

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.