A potential ventilator shortage sparked widespread concern as the U.S. COVID-19 outbreak intensified.
The math suggested that not all people with COVID-induced acute respiratory distress syndrome, or ARDS, would have access to the lifesaving machines that help people breathe.
The problem captured the attention of Nebraska engineer Benjamin Terry and Keely Buesing, a University of Nebraska Medical Center trauma critical care surgeon, who have an ongoing research collaboration focused on ARDS. Building on this expertise, they developed a strategy for stacking two patients on one ventilator.
Their approach, a simple configuration that relies on standard tubing and widely available hardware store supplies, is an option for clinicians who need a quick fix for a temporary ventilator shortage.
“My colleagues and I agree that if we’re looking at two patients and their families, we don’t want to have to make a decision as to who gets the ventilator,” said Buesing, associate professor of surgery.
Their setup tackles the core problem with split ventilation – patient mismatch. This is when patients of different sizes, diagnoses or states of disease progression are candidates for sharing a ventilator.
“My colleagues and I agree that if we’re looking at two patients and their families, we don’t want to have to make a decision as to who gets the ventilator,”Keely Buesing
“My colleagues and I agree that if we’re looking at two patients and their families, we don’t want to have to make a decision as to who gets the ventilator,”
The third scenario is most challenging to frontline physicians because the lungs behave differently depending on how sick a patient is. Under split ventilation, the sicker patient’s lungs take in less oxygen because they’re stiffer and harder to inflate. The healthier patient’s lungs take in more than they need, leading to dangerous hyperinflation.
To solve this, the team used a variable flow restrictor. Adding this device to a split ventilator setup enables respiratory therapists to decrease oxygen volume to the healthier patient without undercutting the sicker patient’s needs.
“We’re using the same tubing system you can buy off the shelf and just modifying it a little bit,” said Terry, associate professor of mechanical and materials engineering. “You could essentially do this setup with stuff from Home Depot.”
While sharing a ventilator is never ideal, the researchers said, their device offers a potentially lifesaving strategy in a crisis situation with no other solutions.
Nebraska’s College of Engineering and Office of Research and Economic Development funded this project.
Nebraska news release: NU researchers create system for sharing ventilator
Media mention: ‘A last-ditch effort thing’: NU researchers create system for sharing ventilator (Lincoln Journal Star, 4/19/2020)
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