As countries affected by the coronavirus pandemic expect to run out of ventilators and other equipment, makers are desperately trying to fill the gap with proposals for open-source, do-it-yourself devices.

Most cases of COVID-19—the disease caused by the novel coronavirus—do not require hospitalization. But for people hospitalized with severe infections, coronavirus damages their lungs and makes it hard to breathe in and circulate the amount of oxygen that their bodies need. Ventilators, machines that provide the lungs with oxygen, are proving to be key to treating these people, who seem to comprise around 10 percent of cases.

Governments are already preparing for what a shortage of ventilators could do to their health care systems.

In a call to U.S. governors on Monday that was shared with The New York Times, President Donald Trump told states not to rely fully on the federal government for equipment. “Respirators, ventilators, all of the equipment—try getting it yourselves,” he said, according to The Times. “We will be backing you, but try getting it yourselves. Point of sales, much better, much more direct if you can get it yourself.”

Anthony Fauci, the director of the National Institute of Allergy and Infectious Diseases, said on CNN that the U.S. has stockpiled 12,700 ventilators, but in a worst-case scenario that number might not be enough. In Italy, he added, physicians are having to make “very tough decisions” about whom to treat.

On the other side of the pond, UK Prime Minister Boris Johnson has urged engineering firms

to switch production to manufacturing ventilators, a call echoed by Secretary of State for Health and Social Care Matt Hancock. “If you produce a ventilator, then we will buy it. No number is too high,” he said on Sky News.

Some believe that makers can do their part to solve the shortage. Julian Botta, a third-year emergency medicine resident at Johns Hopkins University who said his views do not reflect those of the university, put together a Google Doc called “Specifications for simple open source mechanical ventilator.” In it, he lays out the key features of the kinds of ventilators used for coronavirus patients. He also proposes a design for an open-source ventilator after seeing that engineers were interested in designing ventilators but didn’t know much about how they worked.

Several other groups have popped up on various points of the design spectrum, from sharing information to drafting and 3D-printing ventilator parts. Newspeak House, a “hackspace for politics” in the UK, started the Coronavirus Tech Handbook to crowdsource information about COVID-19, including links to open-source equipment designs and other resources. Nathan Young, a resident fellow at Newspeak House who helped create the handbook, wrote in a Medium post that if the hub “causes two people to meet and develop a tool that saves a lot of lives, it just might be the most impactful thing I ever do.”

Despite his proposal, Botta said that the specific features of ventilators do not make them inclined for simple DIY replication.

Before he wrote up his idea for a ventilator, he saw designs posted in Facebook groups (similar ones have popped up on GitHub) that amounted to jerry-rigged continuous positive airway pressure (CPAP) machines—these sorts of devices can’t sense how much oxygen is getting into a patient’s lungs and aren't nuanced enough to support people with coronavirus-caused respiratory distress, he said. His idea, in contrast, contains feedback measures and sensors that would trigger alarms in case of malfunction or inadequate oxygen flow.

Another challenge for DIY or open-source ventilator proposals is approval by hospitals and regulatory agencies. As the burden of the pandemic worsens, regions may see deviations from their standards of care, Botta said, giving the example of triage in Italy. Even so, there is not a straightforward path to implementing DIY ventilators in hospitals.

“It would be very, very challenging to get [open-source ventilators] approved, especially if it's being manufactured essentially by home hobbyists, because there's inherently not much consistency in how things are going to be made,” he said.

Gui Cavalcanti, the founder of “Open Source COVID 19 Medical Supplies," a Facebook group formerly known as the “Open Source Ventilator Project," was made aware of these challenges and decided to pivot away from ventilator design.

An engineer by training, Cavalcanti called first responders in San Francisco who told him to focus instead on other equipment necessary to the public health response, like masks and gloves. “They said, ‘Listen, ventilators are not the issue. The issue is literally everything else,’” he said.

Cavalcanti created the Facebook group last week to act as a repository of information and open-source designs for medical supplies, and it has already grown to over 5,000 members. Cavalcanti said that he and the other leaders of the group are working with distilleries and fabricators to produce hand sanitizer.

One member, Trevor Smale, published preliminary open-source designs of a low-tech ventilator that can be pumped by hand to provide oxygen to a patient. Smale and a handful of close friends, he said in an email, combined designs by groups at MIT and Rice University to create a DIY version of a device known by its brand name as an Ambu bag.

"The chaotic fervor and ideation going on all over the place on various forums and social media platforms meant ideas were atomized and difficult to capture," he said. "After getting some very helpful information and positive reinforcement from experienced front line professionals on the Open Source COVID19 Medical Supplies group and researching elsewhere, I knew that a small, simple and automated ventilator would be a valuable commodity, so I started the GitLab project."

Meanwhile, groups in Italy and Hong Kong have 3D-printed face masks to use personally and donate to hospitals. Isinnova, an Italian startup, 3D-printed 100 valves that connected ventilators to coronavirus patients’ oxygen masks after hearing about a shortage from a local hospital.

Cavalcanti said that he does not see Trump’s statement to governors as a call to action for makers. Though he expects that the group will eventually coordinate with local and state governments, “our main megaphone is going to be getting local makers to make things according to vetted plans,” he said.

He added that the maker and open-source movement can be especially useful for people who cannot access high-quality health care in hospitals by nature of where they live or how overloaded the system becomes.