Science News for Students - Spring 2021

COVID-19 victims could breathe easier with these innovations The low-cost technologies could help oxygen-starved patients around the world The coronavirus pandemic left large numbers of people gasping for air. Many patients with COVID-19 wind up needing extra oxygen. Sometimes they even need to be put on machines that breathe for them. But shortages of these ventilators developed as the pandemic first emerged in 2020. That inspired researchers to explore new low-cost ideas to help these patients breathe more easily. Their work might help both big-city hospitals and medical centers in remote parts of the world. More importantly, what they are engineering could help patients long after the pandemic ends. Shannon Yee is a mechanical engineer at the Georgia Institute of Technology in Atlanta. After hearing of shortages, he recalls, his team asked: “How can we design a low-cost ventilator that can be made globally?” His team and colleagues in England looked at how these ma- chines are used. And they thought about which of their parts might be available nearly anywhere in the world. Most ambulance crews use hand- operated “ambu bags” to help patients breathe. Amachine could be added to squeeze them. And unlike a person, it could work nonstop for days. The simple motor and mechanical system that Yee’s team designed inflates and squeezes the bags. A plug-in power adapter or standard 12-volt battery runs it. Add separate tubing and volume controls and this device can breathe for two patients at once. Filters in the tub- By Kathiann Kowalski

This low-cost ventilator was designed by a U.S.-British team. At its heart are breathing bags commonly carried on ambulances.

ing keep each patient’s exhaled air from infecting others. And the system can hook up to an oxygen supply. Kits can be packaged flat for shipping, Yee says. Other patients might be able to breathe on their own, but not easily. Air contains 21 percent oxygen. But air can be enriched with extra oxygen so that each breath can deliver more of the life- sustaining gas. The common process to concentrate oxygen forces air through an expensive mineral-based material called lithiumX- zeolite. Only a few companies make the zeolite needed to do this. Now research- ers with UniSieve in Switzerland have come up with a non-zeolite alternative. They tweaked a filtering membrane their company had already developed. The membrane has teeny, tiny pores. It works as a filter at the molecular level, notes chemist Elia Schneider at UniSieve. To separate oxygen from the nitrogen in air, the pore diameter must be roughly one-third of a nanometer (bil- lionth of a meter). Using this filter, “We can supply concentrated oxygen on demand,” Schneider says. It fits into a cartridge “There are numerous wonderful ideas about how to help people breathe.” —Shannon Yee

about 30 centimeters (12 inches) long and 4.5 centimeters (1.8 inches) across. A compressor squeezes air into one end. The oxygen gets filtered out and the nitrogen molecules exit into the room’s air. Tubing then carries the concentrat- ed oxygen to a patient. Another new system delivers a mix of helium and oxygen. This mix is lighter than regular air, so it takes less effort to breathe it in, explains Sairam Parthasarathy. He’s a lung doctor at the University of Arizona College of Medi- cine in Tucson. The idea has been known for more than 40 years, he says. But helium is pricey. And patients would need a lot of the mix. Before the pandemic, Parthasarathy had talked about the problemwith Marvin Slepian. He heads the univer- sity’s center for biomedical innovation. Their fix: Recycle the helium that people breathe out. But people also exhale car- bon dioxide and it had to be removed. “We ended up putting a carbon- dioxide scrubber in there,” Slepian says. Scrubbers are devices used to remove materials from a gas. “It is off-the-shelf technology,” he says. “There are numerous wonderful ideas about how to help people breathe,” says Yee at Georgia Tech. “It has been really encouraging to see so many people re- spond and so many great ideas coming out of our universities.” ×

STEVEN NORRIS/GEORGIA TECH

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