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Engineers at the University of California, Davis, are working with clinicians to create a simple, inexpensive ventilator. They have developed a prototype and plan to make plans freely available online. Versions could be in clinical use in about six months.

“This is a critical device to have. It provides the vital functions of a ventilator while being completely portable,” said Andrew Li, assistant professor in the Department of Surgery at 51�ԹϺ��� Davis Health.

The device, named “AmbuBox,” is based on the ambu-bag, a handheld ventilation device. Squeezing the bag by hand pushes air into a patient’s lungs.

There is a gap between the handheld ambu-bag and expensive ventilators used in intensive care units, said Tingrui Pan, professor of biomedical engineering at 51�ԹϺ��� Davis. One attempt to fill this gap is MIT’s E-VENT project, but this device involves a number of mechanical moving parts.

“We felt that we could make a system without moving parts, using compressed air to squeeze and inflate an ambu-bag,” Pan said.

Pan’s laboratory works with microfluidics, devices that move fluids through tiny channels for a variety of applications including medical use. The AmbuBox project meant scaling up their work.

“We control the inflation of the bag with air pressure, so we need to control the valves very precisely. We use a similar approach in microfluidics, so it overlaps with our existing studies,” said graduate student Zecong Fang.

Using available and 3D printed parts

The prototype device consists of components already in hospitals including the ambu-bag, some 3D printed components and a circuit board to control the pneumatic system.

“You just need to control two valves to make the system work. It’s very simple but can work reliably,” Pan said.

The team describe their prototype as “version zero” and hope to have a version available for clinical use in six months.

While the national need for ventilators seems to have abated for now, it’s likely that there will be surges in cases in the future as restrictions are lifted, Li said.

“Ideally, we’ll be able to bring these under control through public health measures, but it’s better to be prepared. Clearly, there’s still a deficit in the total number of ventilators in the U.S. overall,” he said.

The expensive ventilator systems in hospital use offer many more functions for specific high-needs patients. By using a simplified device like the AmbuBox ventilator, doctors could provide basic functions for most patients while reserving more sophisticated equipment for patients who really need it, Li said. 

Additional team members are Ruoyu Zhang, graduate student in electrical and computer engineering; Henry Mai; and Hongcheng Wang, a visiting scholar in the Department of Biomedical Engineering.