Pitching in to Create a New Kind of Safe Mask

Jan Sliwa, A06, M11, an anesthesiologist at Scripps Mercy Hospital in San Diego, had an idea to help protect emergency and operating room doctors from the COVID-19 virus. It started with snorkeling masks.

By design, the masks offer full-face protection. But there was just one hitch. He needed adapters to connect the snorkel side of the mask to antiviral filters widely used in hospitals. That single device, he thought, would eliminate the worry of coming in contact with contaminated air droplets or vapor.

Innovation, as it so often happens, thrives on collaboration, and in this case, it was bicoastal and fast-acting. The manufacturing of the prototype Sliwa envisioned—as designed by Stanford engineers—happened at a Tufts makerspace thanks to the quick response of William Liu, a junior majoring in mechanical engineering.

Liu had been active at the Nolop Fabrication, Analysis, Simulation, and Testing facility—Nolop for short—and was eager for the challenge. “Engineers are about being engaged and being focused on problem solving,” said Liu. “I wanted to do what I could to help.”

“It was great to see William spring into action,” said Barrett Larson, physician founder and director of the Stanford Anesthesia Innovation Lab, where the adapter was designed. “He worked well with engineers at Stanford to make sure the new prototype was printed to exacting specifications, and delivered the first order to California in a matter of days.”

Sliwa had jumpstarted the project along with Larson—they had been residency roommates—and gave the device his seal of approval when it arrived: “It’s comfortable, seals great, and feels safe,” he said. “No fogging/humidity issues.”  

Sliwa said the face mask will protect doctors and other operating and emergency room personnel from aerosolized virus particles in the air, especially during procedures like intubation and extubation, as well as even simple things like suctioning secretions from a patient’s mouth, he said. “These tasks are a small part of my routine practice as a cardiac anesthesiologist, and in this new age of COVID-19, everything becomes significantly more dangerous and puts me at risk of infection,” he said. 

The masks significantly augment other personal protective equipment—or PPE—by using what’s known as a HEPA filter, widely available in operating rooms around the world. “The HEPA filter is essential for inspired and expired air to be virus free and safe to breathe,” he said. “The filters are ideal because we stock them in large quantities in the hospital, especially in the ICU and operating room. Wearing an N95 mask underneath offers another layer of protection, and the snorkel mask, in turn, protects the N95 from external soiling.”

Now, he said “anyone can take our 3D printable design, print an adapter, grab a HEPA filter, and use their snorkel mask to keep themselves safe from coronavirus infection,” he said.

Sliwa praised the team for their quick turnaround. “As a clinician, you almost never see a device idea come to fruition that quickly. For all us here, William and Barrett are heroes,” he said. “They saw a complex problem and rose to the challenge of finding a simple, easily reproducible, and extremely safe way of fixing it.”

Making Use of Tufts Connections

Sliwa said that once COVID-19 hit hard in Italy, “I saw the writing on the wall for what was about to happen in the United States, and to prepare started reading as much as I could about the virus and the Italian experience,” he reported. “I saw these masks being used there and thought they might be a great reusable PPE option for us.”

He reached out to Larson to come up with one-piece plastic adapters to work with Ocean Reef snorkel diving masks. Customization of the adapters, he reasoned, would allow the masks to attach to hospital standard HEPA filters.

The project traveled across country to Tufts thanks to family ties—Sliwa’s father is Krzysztof Sliwa, professor physics and astronomy at Tufts. Krzysztof Sliwa then contacted the Tufts School of Engineering and their 3D printing lab, and soon reached James Intriligator, professor of the practice in mechanical engineering and Human Factors program director. Intriligator reached out to Liu, who was an undergraduate researcher in the human factors lab, and told him about the project.

Liu received the design file for the adapter on March 29, and was drawn immediately to the challenge of figuring how the adapters could be printed on six Prusa 3D printers.

Before he went into full mass production, Liu completed a test round with ten adapters.

They came out well, so he put the printers to work overnight, manufacturing a total of 120. Not all met exacting specifications, but eighty devices measured up. He hustled them over to a Somerville UPS store and they arrived the next morning at Scripps Mercy Hospital and Stanford.

“What Barrett and William accomplished was a one-piece design that eliminated the need for any gaskets or other points of failure—3D printed from a material that didn’t require any post-processing, thereby eliminating any leaks that might let virus sneak in,” said Sliwa. “They were able to do that in under a week—and well in advance of our expected surges in San Diego and Palo Alto.”

“With our limited stock of N95s, I feel so much safer wearing the snorkel mask with HEPA filter attached, and an N95 underneath for added security,” he said. “The innovation also protects N95 masks from exterior soiling, meaning they can be reused, which is important since PPE is in short supply.”

Larson at Stanford credits the “network effect” with quickly catalyzing the process. “It’s just so amazing to me to see—in a matter of hours—that we had connected all the people we needed to make this happen. It meant we could pump this out very fast.”

After hearing the good news from the Scripps Mercy Hospital, Liu sent twenty-one more adapters to three different locations in California. “Barrett told me that they look very promising,” he said, “and I will keep making more to prepare for future supply.”

At the same time, a scuba diving company has wasted no time scaling up production. Ocean Reef Group has launched large-scale commercial production through injection molding, according to their website. Larson added that others who want to 3D print the adapter can access open source files that will work with an Ocean Reef product, the ARIA, a nose-breathing snorkeling mask.

The Right Person at the Right Place

Brandon Stafford, director of the Nolop makerspace at Tufts, said he was not surprised by the alacrity with which Liu approached the printing challenge; he has the kind of creative mind that Nolop, which opened in 2019 as a community makerspace, seeks to encourage. “He and his roommate, Eric Wu, are forces of nature” as engineers, he said. “They just want to build stuff all the time. Nolop is a very satisfying place for them.”

Indeed, Liu has an abiding passion for what he calls visual thinking. Growing up in Shenzhen, China, that skill was honed as he competed with a top-performing robotics team throughout in middle and high school; for six years in a row that same team was chosen to represent China in the Robocup Junior International Competition.

As Tufts he’s continued to excel as a student leader. He is president of the Engineering Student Council and last year he was selected as one of twenty-five Laidlaw Scholars, giving him the opportunity to work across multiple disciplines under the supervision of Intriligator in the Human Factors Research Lab, a catalyst for a wide range of devices for physical and digital prototyping.

With family in China, Liu was concerned about the spread COVID-19 before most of his classmates; his parents were quarantined for two months earlier in the year. Now, as the disease claims thousands of lives across the United States, and as social distancing restricts his own movements, he said he is just trying to his “small part” to bring hope to others. “I wasn’t able to do anything to help my own family,” he said. “So it’s good that now I try to do something here.”

Liu’s expertise with 3D printing has also made him the go-to person yet another medical device, a surgical mask strap for health-care providers at Tufts Medical Center. The Ear Savers, whose plans are available online, hold the elastic straps of a surgical mask, relieving pressure on ears. “Nurses loved it! I’m on my way to Nolop now to mass produce 500 more,” Liu reported on April 13.  

And by being immersed in the inventive, pragmatic opportunities offered by engineering, Liu has an even clearer picture of what he wants to do next. The unexpected bicoastal partnership came at the time he was finishing up his application for graduate school.

“Tufts,” he said, “is the only school I’m applying to. That’s how much I love it.”

Laura Ferguson can be reached at laura.ferguson@tufts.edu.