Sporting and political pundits often argue that attack is the best form of defense but when it comes to the new coronavirus and COVID-19, the disease it causes, the opposite may be true, at least for now. The healthcare workers who are fighting a 24/7 battle against the pandemic desperately need personal protective equipment (PPE) such as gowns, gloves, goggles and masks to shield themselves against the germ.
This includes N95 respirators, “designed to achieve a very close facial fit and very efficient filtration of airborne particles,” according to the U.S. Food and Drug Administration. But as N95 supplies dwindle, United States authorities like the Centers for Disease Control and Prevention have issued recommended guidelines to healthcare providers for the extended use and limited reuse of the masks.
One way of boosting the lifespan of the N95 respirator is by adding an extra line of defense between it and the patient: A transparent plastic shield that wraps around the face and acts as an additional layer to protect against airborne droplets.
This can be easier said than done, but 3D printing, also known as additive manufacturing, can help. Workers at GE Additive — GE’s additive manufacturing business — have designed a sturdy adapter that can quickly convert a standard hard hat and visor into a battle-ready face shield. “It can offer doctors and nurses, who will be wearing these for many hours on end, additional protection and comfort,” says Josh Mook, a Cincinnati-based innovation executive at GE Additive.
The idea was born out of necessity in Ohio. “Our problem is no different from anyone else,” explains Mike Waterman, process improvement director at TriHealth, which is one of the key healthcare providers in greater Cincinnati with four acute care hospitals and 13,000 employees. “As patient volumes grow, we need to manage critical resources such as isolation gowns, N95 masks and other protective equipment, and operate on the assumption that we may not get as many as we want.”
Workers at GE Additive — GE’s additive manufacturing business — have designed a sturdy adapter that can quickly convert a standard hard hat and visor into a battle-ready face shield. “It can offer doctors and nurses, who will be wearing these for many hours on end, additional protection and comfort,” says Josh Mook, a Cincinnati-based innovation executive at GE Additive. Top and above images credit: GE Additive.
The face shields are desirable for any patient-facing healthcare role, but they also are essential for workers executing procedures that may aerosolize the virus. “That’s anything that kicks droplets up into the air, such as intubation,” says Waterman, referring to the process of inserting an endotracheal tube from a ventilator through the mouth and then into the airway to assist a patient’s breathing.
A TriHealth physician reached out to a contact at GE Additive for advice in March and timing was good. GE Additive had recently assembled a COVID-19 task force, a crack team of a dozen engineers, supply chain experts, and legal and finance gurus who can fast-track projects where the business can make a quick, positive difference.
GE Additive is more than capable of printing out entire face shields from scratch. But manufacturing such large objects takes time. Mook estimated that it would consume around 10 hours to print a single face shield. “We didn’t want to reinvent the wheel,” he says. “So we aimed for a solution that was scalable and cost-efficient.”
The basic components that healthcare professionals were using to make their own face shields included clear visors and lightweight hard hats. GE engineers also noticed something else. The hard hats have a common feature: lateral and frontal tabs above the rim that allow the wearer to mount accessories. “You can click things into it,” Mook says.
It did not take them long to design the missing part: a plastic adapter roughly the size of an index finger and shaped like a tiny boomerang that somebody has tried to make straight. One end of the adapter fits snugly into the lateral tab of a standard hard hat, while a nylon twist bolt at the other end holds the visor fast. “You can connect the helmet and shield in less than a minute,” Mook says. “It fits onto almost any combination of hat and shield.”
“Our problem is no different from anyone else,” explains Mike Waterman, process improvement director at TriHealth, which is one of the key healthcare providers in greater Cincinnati with four acute care hospitals and 13,000 employees. “As patient volumes grow, we need to manage critical resources such as isolation gowns, N95 masks and other protective equipment, and operate on the assumption that we may not get as many as we want.” Image credit: GE Additive.
The adapter not only binds together the shield and hard hat, but it also allows the wearer to easily raise and lower the visor as required. More importantly, the device allows healthcare workers to work more comfortably.
Choosing the material was crucial because clinicians usually clean their solid metal, rubber and plastic kit at high temperatures several times per day. The temperature in the high-level disinfectant wash cycle can reach 195 degrees Fahrenheit, says Katie Terry, a senior performance improvement consultant at TriHealth. “It means we couldn’t just use any hobby material,” Mook says. They settled on a high-temperature acrylonitrile butadiene styrene (ABS), a common thermoplastic polymer that is valued for its strength and heat resistance. ABS plastic, as it’s known for short, is used for protective smartphone cases, luggage and flashlights. “It’s also used to manufacture Lego and serves as the plastic casing at the back of our TVs,” explains Mook. ABS is also an amorphous material. “That means it doesn’t really have a melting point per se,” says the GE engineer. That makes it ideal to weather the cauldron of chemical sterilization.
Engineers use a process called fused deposition modeling to print the adapter. It involves heating a spool of ABS wire to a very high temperature and then depositing the molten material exactly where required, layer by layer. Imagine piping intricate buttercream patterns onto a cake to the nearest tenth of a millimeter, and you’re getting close.
It takes around 15 minutes to print an adapter on the 3D printers, which are around the size of two large refrigerators, but engineers have a way to speed up production. “The cool thing about the design we have is that it can be printed in two orientations: standing up, or flat,” Mook explains. Printing them horizontally, like baking a cookie, uses more surface area and limits output. “It uses up real estate,” says Mook. But if engineers print them vertically, like towers, then they can dramatically increase the output.
If healthcare providers wish to print their own, it’s just a question of obtaining the blueprint for the adapter. Even a small hobby-sized 3D printer can manufacture the device, but if customers require scale, Mook says a standard industry machine can produce hundreds of these adapters per day. “Our ideal is to distribute this model to get this in the hands of healthcare professionals so that it can be utilized wherever it’s needed.”
The feedback from the 10 TriHealth clinicians who have tried the prototype has been positive. And when Waterman and Terry circulated photos of the face shield, the orders came in thick and fast. “Around 310 of the 350 models have already been claimed,” says Waterman. “Everyone wants one: all of our four acute care hospitals, our ORs [operating rooms], our EDs (emergency departments), ENT (ear, nose and throat) group, physicians, GI specialists, cardiologists, ICUs, the ambulance surgery sites, and even pediatricians, because kids keep sneezing and coughing.” Adds Waterman: “They have been in use at the Bethesda North ED for several days now and we are getting good reviews.”
In the meantime, TriHealth is piecing together its PPE jigsaw. “We managed to find 350 helmets from an industrial supply company, so we bought them out,” says Waterman. Face shields have been tougher to source, but they have an insurance plan if their search is fruitless. “Josh and his team could always laser cut some visors.”
Waterman and Terry, who both have engineering backgrounds and boast nearly 30 years of manufacturing experience between them, are also working with GE Additive to finesse the face shield. This includes an extra piece, a hood that will address the gap between the lip of the helmet and the shield to provide additional protection against droplet or liquid ingress.
A long journey may lie ahead of the Cincinnati provider but they are staying positive. “Josh and his team were great: creative and energetic,” says Waterman. “To get creative like this requires collaboration,” says Terry. “We are so grateful that we’re able to do that.”