Prototype breathing device created for COVID-19 patients in poor countries

© The University of Leeds

Experts have developed a low-cost and easy-to-use prototype breathing device, designed specifically for poorer-resourced healthcare settings.

Created in response to the surge of COVID-19 cases in low- to middle-income countries, the breathing device provides a form of oxygen therapy called continuous positive airway pressure (CPAP), which has proved effective in helping patients struggling to breathe because of moderate to severe COVID-19.

The breathing aid is the product of a collaboration by engineers, scientists, and doctors from the University of Leeds, Leeds Teaching Hospitals NHS Trust, Bradford Teaching Hospitals NHS Foundation Trust, Medical Aid International, and the Mengo Hospital in Uganda.

Pilot evaluation

A pilot evaluation involving ten healthy volunteers has been completed on the device. From this, the researchers concluded that the device “can be used safely without inducing hypoxia (low levels of oxygen in tissues) or hypercapnia (build-up of carbon dioxide in the bloodstream) and that its use was well tolerated by users, with no adverse events reported.”

The research has been published in the journal Frontiers in Medical Technology.

Explaining the development process behind the device, researchers said that they used the concept of “frugal innovation” to create the breathing aid. This ensured that it remained simple, whilst being robust enough to meet clinical demands in poorer-resourced health settings.

Simple and low cost

A key component to the device is a basic electric fan used to generate air-flow, similar to the fans used to cool electronic devices. The prototype device cost around £150 to make, which is significantly lower than the cost of conventional CPAP machines that start from around £600. A ventilator in an intensive care unit can cost more than £30,000.

Nikil Kapur, Professor of Applied Fluid Dynamics at the University of Leeds and the supervising academic on the project, said: “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.

“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.”

Dr Tom Lawton, Consultant in Critical Care and Anaesthesia at Bradford Teaching Hospitals NHS Foundation Trust and a member of the research team, said: “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.

“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 recent UK study, known as the Recovery-RS Trial, has highlighted how CPAP can provide a valuable intervention for COVID-19, and the World Health Organization is encouraging the rapid development of low-cost breathing aids that could be deployed in poorer-resourced healthcare systems.

For that to be possible, the devices must operate with low-pressure oxygen systems. Unlike in richer countries, clinics and hospitals in poorer settings may not have access to centralised oxygen supplies, where oxygen is piped under pressure to wards, or a steady supply of oxygen cylinders.

Instead, they rely on what are known as oxygen concentrators – machines the size of a suitcase that take in ambient air, strip out the nitrogen, and provide a supply of oxygen at low pressure.

How the machine works

Dr Pete Culmer, Associate Professor in the School of Mechanical Engineering at Leeds and the study’s lead author, said: “The Leeds prototype has been specifically made to work with oxygen concentrators, which have a low flow of oxygen and at low pressure.

“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.”

The device’s fan system provides a safe air flow supply without the need for the more complex and costly control systems of a high-pressure air source. This offers a simple and robust way to generate the sufficient airflow required to open the patient’s airways, so that oxygen can reach the tiny air sacs in the lungs without the risk of adverse effects. The oxygen concentrator is used to enrich this airflow with oxygen, conserving valuable supplies. The device can generate four different levels of air pressure, dependent on clinical need.

The clinical trial found that desirable oxygen saturation levels in the blood – between 96% and 100% – were maintained in the healthy volunteers. The CO2 range at the end of exhalation was between 3.6 and 4.9 pKA, again within accepted healthy limits.

Ugandan trial

A trial of the device involving sick patients is planned to begin at the Mengo Hospital in Kampala, Uganda, in September 2021.

Dr Edith Namulema, an epidemiologist in Uganda involved in the research project, said there is a desperate need for CPAP machines in low- to middle-income countries.

Dr Namulema said: “It is only the regional referral and the national referral hospitals that have access to CPAP. 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.

“Also, as a country, we have about 500 ICU beds for 42 million Ugandans which is very few.”


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