A research group at Yale has successfully developed a new system for splitting a single ventilator among several patients.
The system, called Pressure Regulated Ventilator Splitting or PReVentS, was developed in collaboration by Laura Niklason, professor of anesthesia and biomedical engineering, her research group and the Coalition for Health Innovation in Medical Emergencies, or CHIME. PreVentS is a closed circuit, three vent system that allows a ventilator to be split between two patients, while allowing independent pressure controls, clinical management options and interventions for each patient. The project was originally conceived about four weeks ago, with an open source preprint on the prototype published on April 3. PReVentS is pending regulatory FDA approval, and the researchers are currently in communication with medical device manufacturers to plan how to scale up production after it is approved.
“My group and I have worked to develop a system that should allow the tailoring of ventilator support parameters for different patients,” Niklason said. “Previous ventilator splitting devices have generally provided a way to get ventilator breaths to two patients or more, but they haven’t provided a way to tailor how much ventilator support is provided to each patient. We’ve managed to do that in a system that’s fairly simple and that uses parts that are readily available and off the shelf.”
While the idea of ventilator splitting is being studied by a number of groups, PreVentS is unique in its design to allow independent care for each patient connected to the support, in turn allowing for a higher degree of clinical management options. In traditional splitting systems, individualized air pressure controls — a factor vital to preventing injury to lung tissue in COVID-19 patients — could not be incorporated, thus making the systems unsuitable for multi-day use on COVID-19 patients with ever changing lung and health profiles.
“The issue with traditional ventilator splitting is that if a patient takes a breath on their own, they will actually take air away from the other patient on the circuit,” said Sam Raredon GRD ’20, a student in the Niklason lab and lead graduate student on the project. “If they cough, they will donate air to the other patient on the circuit inappropriately. The purpose of the three vent circuit, as we designed it, is specifically to ameliorate that problem and to make it something that will not happen.”
The prototype developed by Niklason’s group, on the other hand, can be used to split a ventilator between two patients who have entirely different profiles and prevent their breathing from interfering with the other patient. This could be lifesaving during this pandemic, considering the dire shortage of ventilators across the country and the difficulty in quickly manufacturing existing ventilators, as well as that in developing new, inexpensive, free-standing systems.
“The biggest difference is that our ventilators are designed to work under pressure control mode,” Raredon emphasized. “It’s designed to insulate the two patients from each other so that clinicians can individually treat one patient at a time and really throughout that entire process not have to worry about or really have to do any kind of complicated math or adjustments for the other patient. It really keeps the two clinical teams able to operate independently.”
As with much ongoing COVID-19 research, PReVentS was created with the need for rapid development and translation into hospitals in mind. While that consideration now has allowed the product to be in the position to more easily gain FDA approval and be manufactured for use, it added a layer of complexity to the already challenging design process.
“One of the biggest challenges was identifying readily available parts that would all be FDA approvable,” Niklason explained. “The concept of the design was not that difficult but executing the design using parts that are readily available but also would be suitable from an FDA stand point, that was actually the tricky part. And it took a large group of us to identify all those components and figure out the right way of hooking them together.”
Clark Fisher, resident in the department of anesthesiology and collaborator on the project, said the challenge is to design “something that is complex enough to be able to individualize the care of sick patients, but no more complex than it needs to be,” because increased complexity in the design makes mass production more difficult. He noted, however, that PReVentS has found that “sweet spot.”
Given the unique circumstance of the pandemic, traditional paths of moving a product from the research stage to the private sector have been streamlined. In an effort to ensure the nation has enough ventilators, the FDA has been issuing Emergency Use Authorization to allow more flexibility on the types of ventilators that can be used in the United States. Under this context and the urgent need nationwide, PreVentS has the potential to be quickly manufactured.
“We have partnered with a medical device manufacturer who is putting into place procedures to manufacture this at scale,” Niklason stated. “A unique part of the COVID situation is that partners in the private sector were willing to work with us at a very rapid pace which would not normally occur.”
Still, Fisher, Niklason and Raredon all stated that, despite contingent FDA approval, if any truly emergent situations arise at Yale New Haven Hospital, multiple copies of the product are ready for use. Under FDA guidance, during the pandemic, the decision rests with hospitals and clinicians themselves.
Developing a functional system such as this one in merely five weeks is no small feat, but the specific skills of Niklason’s lab have been helpful. Their distinctive combination of expertise in lung physiology and experience building bioreactors for supporting and growing lung tissue, is not too dissimilar from the skills required for building a ventilator. Niklason also credits the University’s culture for the rapid, efficient progress on the project.
“I think this really represents the best of what Yale is about,” she said. “There aren’t too many places that you can pull together such an interdisciplinary project so quickly and have it move forward so well. I think it’s a testament to the culture of innovation that Yale has.”
PreVentS is one of two multi-patient ventilator systems being developed at Yale.
Maya Geradi | firstname.lastname@example.org