In March, as the coronavirus pandemic swept through China and began hitting Europe, before stay-at-home orders and worst-case global coronavirus deaths were predicted into the hundreds of thousands of people, medical professionals began to worry about whether there were enough ventilators for all the patients who would need them.


A team of U-M doctors specializing in creating medical inventions through 3D printing started brainstorming. One week after creating sketches in a notebook, they had a working prototype for a new type of device to split one ventilator between multiple patients — in a way that solves one of the primary concerns of that controversial, last-resort practice: the lack of the ability for doctors to make individual oxygen adjustments for each connected patient.


The doctors group, MakeMedical LLC, has applied for a patent on its VentMI device. It has been tested on animals and received authorization from the U.S. Food and Drug Administration for emergency use amid the coronavirus pandemic.


Worst-case scenarios for ventilator shortages haven't materialized, but the Michigan Medicine team's individualized vent-splitter still has potential usefulness going forward. They're making and distributing the devices to interested hospitals only at their cost, not for profit.


"We have a team that prides itself on being able to move quickly on concepts and then in the manufacturing through our use of 3D printing, beating corporations with budgets of hundreds of millions of dollars," said Dr. Glenn Green, a pediatric ear, nose and throat surgeon at Michigan Medicine's C.S. Mott Children's Hospital, a co-developer of the technology.


Ventilators help patients who can't breathe on their own, or who need assistance, to inhale and exhale. The sickest among coronavirus patients frequently have lung complications, including pneumonia, and are in need of the devices.


The concept of splitting a ventilator to serve more than one patient at a time has been understood as possible by the medical community — a Detroit emergency physician, Dr. Charlene Irvin Babcock, helped prove the viability of the concept in research more than 15 years ago.


But there's a key drawback: a split ventilator only delivers one, preset pressure to all patients sharing it, and how one connected person breathes affects the breathing of others.


A doctor, in an overwhelmed emergency room, would have to match similarly sick, similarly sized patients with almost the same lung function, and then be ready to switch them out to other ventilators as their breathing improved or worsened.


"It reaches the point where it's impossible," Green said.


The VentMI device allows doctors to individualize air flows to each connected person, through a regulator similar to that on a scuba diver's air tank.


"A diver who's used half of the air in his tank doesn't want it to deliver only the half the air it did when it was full," he said. "A regulator helps maintain the desired air pressure."


Green credited partner Dr. Kyle VanKoevering with the initial concept. VanKoevering works in the head and neck surgery department at Michigan Medicine and is an associate faculty member in U-M's Department of Biomedical Engineering.


Other partners on the project include Mott pediatric head and neck surgeon Dr. David Zopf, and Owen Tien, founder of the Ann Arbor-based 3D printing company Thingsmiths.


Tien has worked with the Michigan Medical group for about two years on developing various medical devices.


"We have a set of skills that allow us to be pretty quick," Tien said. "The medical side of our team has a high familiarity with 3D printing and rapid manufacturing."


The printer creates the prototypes out of a type of plastic approved for dental devices, he said. MakeMedical has partnered with Grand Rapids company Autocam Medical, which, as of Friday, had created 25 "fully validated, medical-grade aluminum, ready-to-go" devices for any hospital that needs them, Tien said. It took only four weeks from the first conceptual sketches.


While other MakeMedical devices have been for-profit, the VentMI is not.


"The primary goal for this was having a device ready for this crisis, if it was needed," Tien said.


While that projected need for ventilators didn't materialize, the director for the U.S. Centers for Disease Control and Prevention has predicted that a second wave of coronavirus outbreak heading into next winter could hit harder than the current outbreak. Whether that proves true, the VentMI still has practicality going forward, Tien said.


"It's a lot easier to have a box with five VentMIs in a closet than it is to have five ventilators that you don't normally use," Tien said. "This would be a great stopgap measure if you had a rural hospital that encountered a mass casualty event, until you could bring other ventilators in. Or overseas, perhaps in less-developed areas of the world where they only have one ventilator all the time."


It's still not an optimal choice for doctors, Tien noted.


"It's only for use in the direst of circumstances," he said. "But if you have made the decision to split the ventilator, using a device like our VentMI gives the control back to the health provider that they are used to when venting patients."


Hospitals and medical centers interested in obtaining VentMI at-cost may inquire at makemedical.net.