Invention Awards: An Inexpensive, Portable Ventilator

An inexpensive portable ventilator designed to save lives during a pandemic

Air Supply

Matthew Callaghan's OneBreath is portable and just a fraction of the cost of conventional ventilators, making it ideal for use during a pandemic.

Check out today's featured Invention Award winner, OneBreath, a portable ventilator that saves more lives for less cost.

Four years ago, when Matthew Callaghan was a surgery intern at the University of California at San Francisco, the medical world was buzzing over the prospect of a global flu pandemic. One of the biggest potential problems was logistical: Because 95 percent of the ventilators in the U.S.—which keep critically ill patients breathing when their respiratory system is unable to function—are already in use, thousands of patients would die for lack of available life support. Ventilators cost hospitals from $3,000 up to $40,000 for state-of-the-art models, making it impractical for most hospitals and clinics to stockpile them for emergencies.

Invention: OneBreath
Inventor: Matthew Callaghan
Cost: $160,000
Time: 4 years
Is It Ready Yet? **1 2 3 4 5

Callaghan, now a postdoctoral fellow in Stanford University's biodesign program, knew that in a pandemic situation, hospitals would have to come up with triage procedures that would leave some to die. If he could develop a reliable, no-frills ventilator, it would eliminate many such heart-wrenching decisions. "I thought, these ventilators cost 40 grand, and they just push air around. It isn't complicated engineering. You don't need all the bells and whistles." That thought was the impetus behind the OneBreath, the ventilator Callaghan invented with a small team of fellow Stanford biodesign students. The device is just a fraction of the cost of a low-end conventional ventilator, runs on a 12-volt battery for six to 12 hours at a time, and is smaller than a toolbox so it can be easily deployed wherever needed.

Whereas most ventilators use expensive flow sensors, servo motors and other specialized components to push air in and out of the lungs, Callaghan started from scratch with a basic pressure sensor, typically used in devices like blood-pressure meters, that cost about $10. As an air compressor forces air into the chest, the sensor, connected to a tube inserted into the mouth, measures the airway pressure. Software uses the pressure sensor's data to calculate the volume of breath in the lungs—this allows the ventilator to sense when the patient needs to take another breath, at which point the software directs the compressor to supply the air through a valve system. If the patient is beginning to be able to breathe on his own, the software instructs the compressor to supply less air, a feature that helps recovering patients gradually begin to breathe independently again. Other low-cost compressors don't have this kind of fine-tuned ability to adjust to individual needs.

How OneBreath Works

Software calculates how much air is in the patient's lungs based on data from a sensor, and then directs a compressor to deliver more air through a valve system.Paul Wootton

Callaghan also replaced the single permanent air valve on expensive respirators, which requires time-consuming cleaning between patients, with two—one that is exposed to patient air, and one that never comes into contact with it. When the inner valve opens as the patient inhales, air forces the outer valve closed, keeping air that the patient expels from contacting the pristine inner valve. The contaminated outer valve can be thrown out and replaced with a new one.

A round of successful tests on pigs wrapped up last December, and the FDA is expected to review the device for humans this fall. The OneBreath should not need to undergo clinical trials, Callaghan says, since it performs the same air-moving function as existing ventilators. He anticipates that the U.S. government will want to stockpile the device for use during pandemics, but clinicians who have been privy to the OneBreath's development are excited about its prospects elsewhere as well. "Lots of second- and third-world countries have precious little access to ventilators at all," says Stephen Ruoss, the medical director of Stanford Respiratory Care Services. "This is a slickly engineered solution."
Regardless of whether the device turns out to be a moneymaker, Callaghan thinks watching critically ill patients improve will make his efforts worthwhile. "In routine use of this, you're going to save lives. You don't want people to think, 'Am I going to have to duke it out for a ventilator with someone else?'"