Bijal Rajput was 16 and an emergency medical technician-in-training when she learned how to use a tourniquet, an ages-old technique of tying up a wounded limb to slow severe bleeding. Tourniquets are simple, reliable, sturdy and, in many cases, life-saving.

But Bijal, an ambitious high school student and aspiring doctor, was struck by how “imprecise” the procedure of applying a tourniquet was, with rescuers relying largely on visual cues.

She wondered if there was a better way.

Now 17, Bijal and six of her classmates at the Thomas Jefferson High School for Science and Technology have come up with an idea for a self-adjusting tourniquet that would be affordable enough to be deployed in developing countries — where a wounded person could be hours or days away from a hospital — and simple enough to be used by people without any medical training.

“This is a really simple problem,” Bijal said. “You’ll find all across the world people get cuts and injuries that can be potentially really dangerous. A tourniquet that’s easy to use, that’s automatic, can help them out a lot.”

The team was awarded a $10,000 grant from Lemelson-MIT, a program that encourages and supports inventors and is best known for its signature $500,000 prize for mid-career inventors. The team — whose members include seniors Bijal, Gabriel Margolis, Lavanya Shukla, Dhriti Vij, Junyoung Hwang, Jonathan Zheng, and William Zhang — was one of 14 high school teams selected for grants. The money will help the team move closer to a prototype.

Though experts say the life-saving benefits of using tourniquets far outweigh the risks, Bijal found research that showed that tourniquets, applied too tightly, can sometimes harm patients.

“Based on bad tourniquet usage, patients would end up with complication of circulation and nerve damage,” Bijal said. “You just apply the tourniquet based on what you see and that’s not a very specific procedure.”

Doctors already use automatic tourniquets in surgical settings, but the devices are expensive, large and cumbersome, making them impractical to use in the field. The students proposed using the same ideas already in place in the expensive hospital devices to create a device that’s smaller, cheaper and easier to use. Their device would be similar to a blood pressure cuff — inflating to apply a specific amount of pressure to a limb — and would use sensors and a computer chip to determine exactly how much pressure is needed.

Joshua Schuler, executive director of the Lemelson-MIT program, said it’s impressive that the students are challenging the status quo.

“These students were curious: Why can’t the tourniquet in the field be more like the tourniquet in the hospital?” Schuler said.

Emergency medicine experts said the risks associated with tourniquets are relatively small. When a wounded person risks dying from blood loss, tourniquets pose “a low risk of danger compared to all the good you can do,” said Corey Slovis, the chairman of the department of emergency medicine at Vanderbilt University Medical Center in Nashville, Tenn. The longer the tourniquet is on, the greater the risks. And in the United States, where a person is never too far from a hospital, tourniquets are used briefly.

In developing countries, a wounded person could wait hours or days to get to a hospital. Bijal was inspired in part by a Doctors Without Borders article that chronicled the story of a man in the Central African Republic who lost his leg because a tourniquet was applied too tightly.

The students who developed the proposal said the project is an opportunity to integrate lessons from many classes to solve a real-world problem.

“I just wanted to tie together everything I learned in school,” said 17-year-old Jonathan Zheng. “I just really like in general designing and creating something useful.”