The Politecnico team, which is coordinated by Professors Simone Cinquemani, Luigi De Nardo and Paolo Rocco, along with Professors Matteo Corno, Beniamino Fiore and Raffaele Dellacà, has designed a mechanical ventilator that could support hospitals in new health emergencies. Cinquemani said, “During the early phases of the epidemic, we had to deal with a limited availability of ventilators, which are complex, expensive machines with a long manufacturing process. This project was launched to address a scenario in which a massive and unexpected number of people in respiratory distress requiring ‘hands-on’ assistance can be treated with an easy-to-use machine that has the technology to replace medical staff, thus buying time and allowing everyone to be put on a ventilator. Breath4U can save lives by using an ambu bag that is rhythmically compressed by the hands of trained people or by a ventilator that replaces those hands.”
The device has been designed and developed in collaboration with Whirlpool Corporation, which has recently signed a framework agreement with Politecnico to work together on research projects. “This is one of many cases in which the company wants to create synergy between its innovation needs and our capacity of provisioning the necessary skills for mechanical, electronical and computational design,” added Cinquemani. “The project was challenging due to its multidisciplinarity and required us to use clinical and biomedical competences. Another challenge was how quickly we had to work: in one month we went from a blank page to a layout that was easy and fast to build.”
Breath4U is light and easy to install, with simple components that are available on the market even during a lockdown. Manufacturing a single device should cost about 1,000 euros, while a traditional ICU ventilator tends to cost from 10 to 40 thousand euros.
The mechanical part is composed of a classic ambu bag that is automatically compressed by two motorized clamps applying controlled pressure. The clamp movement is determined by a series of measurements taken in the field, e.g. the patient’s blood pressure and breathing volume, maximum air pressure, etc. The ambu bag is connected to a respiratory mask via a plastic tube, as the prototype has been designed for non-invasive intubation.
The clamp movement is managed by control electronics. “I was responsible for developing the control law using only standard electronic components that are readily available,” said Corno. The control system allows the machine to have two functions. The first is simply volume control for patients who are not breathing autonomously. Doctors or medical staff can set the respiratory parameters, i.e. number of breaths per minute and volume to be administered, via a graphic interface. The machine can then deliver air at the speed and volume indicated, ensuring that safety limits regarding the amount of pressure that compromised lungs can tolerate are not exceeded.
Corno continued, “Designing a control law for assisted breathing was much more complex, as the machine must ‘listen’ to the patient to know when they begin inhaling. Breath4U measures the pressure difference between the end of one expiration and the start of the next inspiration. Respiratory-compromised patients are not able to create enough negative pressure to inhale all the air they need; thus, the machine helps them by measuring the amount needed.”
After being assembled, the prototype was first tested in the TechRes – Laboratory of Respiration Technologies of Politecnico di Milano using a device that acted as a patient’s lung . Several units were sent to certifying bodies to be assessed for safe use in hospitals, while others are being tested at the Fondazione Poliambulanza in Brescia (Dr. G. Natalini), the Santa Maria della Misericordia Hospital in Perugia (Dr. M. Renzini) and the Provincial Hospital in Macerata (Dr. F. Corradetti).
The project will be finalized in the next weeks. Once completed, it will be available as an open source technology for anyone looking to speed up the device production.
This article was first published on 26 July by Politecnico di Milano.
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