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The machine provides a form of oxygen therapy called ‘continuous positive airway pressure’ or CPAP, which has been one of the main tools available to medical staff for treating serious cases of coronavirus infection where patients are struggling to breathe unaided.
In a
paper published today in the journal
Frontiers in Medical Technology, researchers describe the creation of a pilot device that could help treat the ongoing Covid surges in low and middle income countries.
They used the principles of “frugal innovation” to design and develop the breathing aid – aiming to create a device that was both simple and robust enough to meet clinical demands in poorer-resourced health settings.
The components for the device cost around £150, compared to £600 for a conventional CPAP machine, and more than £30,000 for a ventilator used in an intensive care unit.
“By adopting the approach of frugal innovation, we have been able to redesign an important piece of medical equipment so it can function effectively in poorer resourced healthcare settings,” says Nikil Kapur, Professor of Applied Fluid Dynamics at the University of Leeds and the supervising academic on the project. “We have stripped away unnecessary complexity and ensured the device will work in settings where oxygen supplies are scarce and need to be conserved. The prototype is an important step in developing a device that will create greater access to critical-care technology and help save lives.”
One key innovation was the use of a simple electric fan to generate the required air flow – overcoming the lack of access to supplies of pressurised air and oxygen. This provides a safe flow of air without requiring expensive control systems of high-pressure air. The airflow needs to be sufficient to open the patient’s airways so oxygen can get into the tiny air sacs in the lungs. The machine can generate four different levels of air pressure.
“The Leeds prototype has been specifically made to work with oxygen concentrators, which have a low flow of oxygen and at low pressure,” says Dr Pete Culmer, Associate Professor in the School of Mechanical Engineering at Leeds and the study’s lead author. “The fan or CPAP blower is connected to what is known as a breathing circuit. That circuit is made up of a filter to catch viruses and bacteria in the air flow, tubing, face mask, a valve which controls the flow of oxygen from the oxygen concentrator, and an expiration outlet.”
“In the UK, CPAP has been effective as the mainstay of respiratory treatment for severe Covid-19 and helps to keep patients from needing advanced ICU care such as ventilators,” says Dr Tom Lawton, Consultant in Critical Care and Anaesthesia at Bradford Teaching Hospitals NHS Foundation Trust and a member of the research team. “In many countries, resource limitations mean that even CPAP is difficult to come by and more severe disease frequently leads to death. Simple CPAP devices, designed to operate in a resource-limited setting, can help reduce global healthcare inequality and save lives both now with Covid-19 and potentially with other diseases in the future.”
A small trial of the device involving ten healthy volunteers demonstrated that it could be used safely without adverse changes in oxygen or carbon dioxide level, and with no adverse events reported.
The next step is a trial with sick patients at a hospital in Uganda in September. There is a desperate need for CPAP machines in low and middle income countries, according to Edith Namulema, an epidemiologist in Uganda who is involved in the project. “It is only the regional referral and the national referral hospitals that have access to CPAP,” she says. “Yet patients first present to the lower-level facilities when they have breathing difficulties and by the time they arrive to the regional referral centres, in some cases, it is too late. The ability to hook a patient onto ventilation when they need it potentially saves many lives and reduces the hospital stay.”
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