A “neural tourniquet” doesn’t sound like a thing that should work. Even its inventors admit it.
“It’s a real leap of faith: ‘I know, we’ll stimulate a nerve to control bleeding!’” says Chris Czura, a vice-president of the Feinstein Institute for Medical Research, on Long Island.“When you say this to surgeons, they look at you funny.”
But 15 years of research by the Feinstein team has built up ample evidence for this example of bioelectronic medicine, which uses neural stimulation to prevent or stop life-threatening hemorrhages. Now the researchers are launching a major clinical trial to show the world that their strange idea doesn’t just work, it can save lives.
This tech is nothing like typical tourniquets, which have been used since Alexander the Great’s military campaigns in ancient Persia. When one of Alexander’s soldiers was wounded, his physicians tied a rope around the soldier’s limb above the wound, compressing the blood vessels and stopping the blood flow. And the technique hasn’t changed much since then. In today’s emergency medicine, first responders still do much the same.
With the neural tourniquet, there’s no rope and no physical compression of the blood vessel. Instead, doctors press a handheld device against the skin (Czura won’t say exactly where, citing proprietary info) to stimulate the vagus nerve, which transmits information between the brain and the major organs. The nerve stimulation conveys a signal to the spleen, where the platelet blood cells that form clots receive their instructions. This signal “primes” the platelets, prepping them to form clots if they encounter a wound anywhere in the body.
“This grabs control of the mechanism the brain uses,” Czura says. “The body has this natural physiologic pathway to control bleeding, and this just ramps it up.”
An earlier study in pigs found that the neural tourniquet reduced bleeding time by 40 percent and volume of blood loss by 50 percent. And it worked quickly. Within three minutes of jolting the pig’s nerve, the researchers measured an increase in an enzyme associated with clotting at the site of injury, while enzyme levels remained steady elsewhere in the body. Animal studies have also shown that the tech worked for both external and internal injuries.
Czura and his colleagues say the neural tourniquet could be useful for battlefield medicine, emergency response, surgery, and postpartum care. The tech is being developed by a company called Sanguistat, the Feinstein Institute’s second spin-off. (IEEE Spectrum covered its first spin-off, SetPoint Medical, in a feature article about vagus nerve hacking.)
The tech will get its first tryout as a treatment for postpartum hemorrhage, the leading cause of maternal death around the world: In Africa and Asia, it kills close to 80,000 women each year. In partnership with the Bill Gates-backed Global Good Fund, the Feinstein and Sanguistat researchers are launching clinical trials in the United States and in the developing world (exact locations TBD).
Feinstein researcher and trauma surgeon Jared Huston hopes the neural tourniquet will become a new tool for surgeons. Before an operation, the stimulator could be applied as a protective measure against hemorrhage, he says, in the same way that patients get antibiotics before surgery to protect against infection. Huston would also like to have a better treatment for emergency room patients, noting that he recently had a 30-year-old patient die from blood loss after a motorcycle accident. “If the surgeon doesn’t get in there to stop the bleeding in time, it’s game over,” he says.
A bioelectronic solution to bleeding wouldn’t replace a pharmacological one; it would offer something completely new, Huston says. “I consider bleeding a disease that no one talks about,” he says. “We don’t talk about it because there’s nothing to be done about it—so we sweep it under the rug and hope things go well. But as a surgeon, I can tell you that often things just don’t go well.”