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The Engineers Taking on the Ventilator Shortage

The newest designs are smart, streamlined, and inexpensive. Will they be enough?

On Monday, March 9th, Jake Kittell, a research engineer and machinist who builds scientific equipment for the University of Vermont, in Burlington, came into work fired up. Approaching another engineer, Carl Silver, he said, “We gotta build a ventilator.”

“That sounds great,” Silver replied. “What do we know about ventilators?”

Neither had ever seen one. But the coronavirus pandemic, once an abstraction, had recently made itself felt in Seattle, New York, and other American cities, and doctors had warned that a shortage of ventilators could hasten the deaths of thousands. “You feel like you want to do something,” Silver recalled. The next week, Kittell e-mailed another professor at the university, Jason Bates, with whom they had worked in the past, and whom they knew to be a lung expert. We have a shop, he wrote. Can we build a ventilator?

Well, sure, Bates thought. He’d been working on the same problem for the previous four days.

Bates has wispy white hair and speaks with lucid, cheery confidence. Originally from England, he is a professor of medicine and of biomedical engineering, and teaches in both the university’s engineering department and its medical school. The author of “Lung Mechanics: An Inverse Modeling Approach,” he is one of the world’s foremost experts on ventilator-induced lung injury, or vili. Earlier in his career, at McGill University, in Montreal, Bates and his team invented a computer-controlled ventilator for mice that is still used by researchers. By tuning the machine’s settings and seeing how a mouse’s lungs react under pressure, scientists can study the physiology of lung disease. They can also explore how different styles of ventilation—in which air is moved into and out of the lungs at various volumes, pressures, and rhythms—can help or hurt a damaged lung.

The previous Friday, March 13th, Bates had heard from Matt Kinsey, a pulmonologist at the University of Vermont medical school. A covid-19 patient there had been placed on a ventilator, and the physician in charge had decided to use a technique known as airway pressure release ventilation, or A.P.R.V., in which the device delivers near-constant air pressure, with an occasional quick release. (Try taking a long, slow breath in, then puffing out, quickly but gently; repeat.) Kinsey passed on a text message from the physician: “APRV is da bomb for covid.” Bates said, “I was intrigued by this because I’d been studying A.P.R.V. and trying to figure out how to optimally deliver it.” He suspected that covid-19 inflicted more damage when the lungs were swinging between full inflation and full deflation, and had come to believe that A.P.R.V., by avoiding those extremes, was probably the gentlest ventilation strategy for those suffering from the disease. Now his theory was being put to the test.

The ventilators used in today’s I.C.U.s are expensive, in large part because they are configurable. Newer models have touch screens that allow clinicians to change and track dozens of parameters, carefully adjusting how breaths are delivered. Bates began wondering whether it might be possible to build a pared-down ventilator that did nothing but provide A.P.R.V., to be used when the supply of fancier ventilators ran out. A typical I.C.U. ventilator costs between twenty-five thousand and fifty thousand dollars. Bates replied to Kittell’s e-mail with a document titled “APRV for $10 (okay, maybe $50 . . . ).”

In an included schematic, Bates had sketched a simple device: a box with three holes in it. Gas under pressure—which many hospitals have available from wall outlets—would flow into one hole and out another, to the patient. In normal breathing, exhalation typically takes about two to three times as long as inhalation; in A.P.R.V., the length of exhalation is reduced from several seconds to about half a second, while inhalation can take five seconds or more. To create this modified rhythm, the box’s third hole would be blocked by a rotating disk that also had a hole in it, and that was spun by a motor. When the holes briefly aligned, the machine would exhale through the opening.

By the next day, Silver had built a prototype and sent Bates a video. A rubber glove was attached to the side of a box with some zip ties. The glove inflated, then deflated, then inflated again. “I saw that and everything changed,” Bates said. Soon, the university agreed to fund the device. Kittell and Silver were given free rein in the shop; a lung analogue was brought in from the hospital for testing; a regulatory expert began preparing an emergency report for the Food and Drug Administration, which had created a special approval process for stopgap ventilators; and several local contract manufacturers were lined up so that the device, now known as the Vermontilator, could be mass-produced.

Engineering is quiet, methodical work, not often the stuff of high drama. But for many engineers the coronavirus has been a call to arms. Not since the space race has the whole world been so invested in problems that are fundamentally technical. During the Apollo 13 mission, a buildup of carbon dioxide was slowly poisoning the crew; the nation watched as the astronauts, working with engineers in Mission Control, jury-rigged a filter using duct tape and spare parts. In the film “Apollo 13,” from 1995, an engineer with a pocket protector explains the situation to his colleagues: “The people upstairs handed us this one, and we gotta come through.”

Since February, engineers in industry and academia have been working on designs for cheap, easy-to-build ventilators. Ford has christened its effort Project Apollo. And yet comparisons to the moon landings may understate the complexity of the problem. covid-19 is a mysterious illness, and ventilators admit to many styles of operation. In the best case, the machines keep patients with failing lungs alive, buying time for the body to heal. In the worst case, they can aggravate lung damage. In the course of the pandemic, critical-care specialists have disagreed about how the devices should be operated and at what point in a patient’s decline they should be used; mortality rates for covid-19 patients on ventilators have ranged widely. Manufacturing a ventilator is difficult, especially during a pandemic, when supply lines are unreliable. Different designs negotiate different bargains between cost and functionality. Reaching the moon is challenging enough. It’s harder when no one is sure where the moon is.

The lung is a passive participant in breathing. It’s the diaphragm, a large muscle that cuts the human body horizontally in half, that does the work. When you inhale, your diaphragm pulls down like a piston, creating negative pressure around the lungs, while the muscles of the chest wall pull up and out. Air, drawn in through the nose and the mouth, flows through the trachea and into the bronchial tree, which fans out into the lungs. There, the breath nestles into hundreds of millions of gossamer sacs called alveoli. Blood, meanwhile, has arrived at the rendezvous through a network of capillaries, the smallest vessels in the circulatory system. Under a microscope, the alveoli look like bunches of grapes, and the capillaries like the mesh sacks that hold them. The tissues are so exquisitely thin that oxygen and carbon dioxide can diffuse across them, between air and blood. The contact surface between the two networks, if it were unfolded flat, would be more than half the size of a tennis court.

The alveolar flesh is elastic, and delicate like fruit pulp. It fares poorly when infected. The coronavirus multiplies in the alveolar cells, tearing them apart as it escapes; in the resulting chaos, fluid can leak into the air sacs, capillaries can constrict or clot, and tissues can become inflamed and stiffen. As the infection spreads, the number of healthy air sacs declines, and the exchange of gases becomes less efficient. A patient whose lung function degrades in this way can develop acute respiratory distress syndrome, or ards.

When a covid-19 patient arrives at the hospital with shortness of breath, physicians use a pulse oximeter, clipped to a finger, to monitor her blood-oxygen level, while supplemental oxygen is delivered. If the oxygen level continues to decline, doctors bring in a ventilator. A device that looks like an oversized shoehorn is wedged over the patient’s tongue and used to peel back the epiglottis. Then a tube is fed down the trachea, where a small balloon is inflated to hold it in place. Patients are usually sedated and paralyzed before being intubated; people suffering from covid-19 may have to stay on ventilators for weeks, remaining sedated for the duration, and they are sometimes paralyzed again if their movement makes them hard to manage. It is an extreme intervention that, even when it saves a patient’s life, takes a toll on the body.

At the most basic level, a ventilator is a pump, no different from the plastic resuscitator bags that paramedics squeeze to push air into a patient’s lungs, in lieu of mouth-to-mouth. But, to avoid vili, the lungs must be ventilated with care. Too little air pressure and the alveoli won’t inflate; too much and they’ll distend and get damaged. The balance grows harder to maintain as ards progresses. The lung is like a lattice, with each air sac supporting its neighbors. Damaged alveoli can press up against one another, spreading weakness with each breath; strained alveoli can burst. During exhalation, the insides of the alveoli, which get stickier as they fill with fluid, touch and cling together; inflating them again requires peeling them apart. In lung-physiology circles, this is sometimes called the “Velcro effect.” “If you have that Velcro effect going on with every single breath, breath after breath, that’s incredibly damaging in a fairly short time,” Bates said. “You get in this vicious spiral that’s really hard to get back from.”

With a typical I.C.U. ventilator, a clinician has a few ways to modulate the flow of air. She can adjust the “tidal volume”—the total amount of air to be delivered with each breath. She can designate a target pressure, in which case the ventilator delivers whatever volume is required to generate it. (Imagine filling a bicycle tire: you pump until the tire is firm.) She can also select the degree of peep, or positive end-expiratory pressure—the amount of pressure that’s left in the lungs at the end of each exhalation. Higher peep prevents the air sacs from collapsing. By decreasing the duration of exhalation and maintaining higher inspiratory pressure, A.P.R.V., Bates’s preferred ventilation style, does everything possible to avoid the Velcro effect.

The Vermontilator will likely cost around one or two thousand dollars when it ships—more than ten (or fifty) dollars, but a fraction of the cost of a full-fledged I.C.U. ventilator. It’s so inexpensive because it’s a minimalist device made from around fifteen parts, designed specifically for A.P.R.V. If the Velcro effect is as central to covid-19 as Bates believes it to be, then this is a sound approach. But clinicians and researchers are still debating what kind of lung damage the coronavirus causes; they have come to recognize that it affects patients in unpredictable ways. “One of our mistakes at the beginning of this mass-casualty event was fixation: you come in with an idée fixe,” Sharon Einav, an I.C.U. specialist in Jerusalem who co-authored a set of well-known guidelines for critical-care surges, told me. “People knew ards. The intensive-care community has been discussing ards for the last twenty years. As time passes, we’re discovering that this disease has something more to it.” The Vermontilator is a bet on the nature of the virus that may not pay off.

If we could produce more of the high-end ventilators already in use in hospitals, doctors could choose their own settings. This is the cause now taken up by Ford and General Motors, which have each collaborated with a ventilator-maker—G.E. Healthcare, which licenses a design from Airon, and Ventec, respectively—to scale up manufacturing. In mid-March, Ford kicked off Project Apollo, after the company learned about Airon’s design; a personal introduction to representatives at Ventec led Mary T. Barra, the C.E.O. of G.M., to commit her company to Project V.

Ventec’s vocsn ventilator—the name stands for “ventilator, oxygen, cough, suction, and nebulizer”—was designed to perform the functions of five devices in one. “We are the first and only multifunction ventilator,” Chris Brooks, the company’s chief strategy officer, told me. (The vocsn was approved by the F.D.A. in 2017.) For G.M., Ventec has created a simplified version, without the cough, suction, and nebulizer functions, known as the V+Pro. Even so, Brooks sees it as a fighter jet in a race with prop planes. “There’s been a lot of conversation over the past few weeks with the shortage, a lot of very well-intentioned individuals and groups and very smart people, who have said, ‘Hey, we can create a ventilator,’ and ‘Hey, we’ve developed a ventilator overnight, it’s a hundred-dollar ventilator,’ ” he said. “There’s a reason that there are very high-end, very powerful and precise critical-care I.C.U. ventilators. That truly is what these patients need.”

On March 27th, in a tweet, President Trump urged G.M. to “START MAKING VENTILATORS, NOW!!!!!!”; in a subsequent tweet, he invoked the Defense Production Act to compel the company to do what it had started doing two weeks earlier. Preparing to manufacture ten thousand of Ventec’s ventilators per month, as G.M. plans to do, has required a crash effort. On March 19th, G.M. flew six engineers to Bothell, Washington, to study the vocsn production process. “We took a lot of pictures and a lot of video,” Gerald Johnson, G.M.’s head of global manufacturing, told me. The vocsn has around seven hundred parts; the V+Pro, around four hundred. By e-mailing lists of parts to around seventy of its “Tier 1” suppliers, G.M. was able to secure all of them by the following weekend. The scramble, Johnson said, was “miraculous.” Suppliers had to adapt production lines to new specifications; they had to ask their own suppliers to do the same. The most elusive part, a special DC motor, is being shipped from India, where it is being made in a factory that had closed and had to be reopened.

With the parts secured, a G.M. component-manufacturing facility in Kokomo, Indiana, was retrofitted for ventilators. Two hundred and fifty skilled workers, recruited from within and outside G.M., began work after a week of training. A few dozen Ventec engineers are helping run the operation. At stations, each person takes on a sub-assembly task—plugging in a hose, mounting a circuit board with tiny screws—and then passes a bucket containing the incomplete ventilator to someone else. “Because of the urgency and speed, automation was kept down,” Johnson said.

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