Systematic Design, Control, and Parametric Testing of an Automated Resuscitator Bag Mechanical Ventilator

Abstract

The COVID-19 crisis has revealed and exacerbated a shortage of mechanical ventilators in hospitals around the world, regardless of their government’s resources. Where some countries can respond to the situation by ordering more high-end ventilators, the price is often too high for low- and middle-income countries (LMICs) and securing them can be difficult. The goal of this work is to design, prototype, and test a low-cost ventilator, called ETH breathe, based on the automated compression of a resuscitator bag. A holistic and systematic design approach is taken to create a compact and adaptable device that can safely meet the current requirements. This is achieved by using 72% standard parts out of 33 (72%) and prioritizing compactness in the mechanical design. The control system is developed to provide both continuous mandatory ventilation (CMV) and spontaneous breathing support or assist control (AC), which significantly extends the potential use cases beyond patient sedation. The prototype is tested for accuracy, modularity, and oxygen response using a full physiological artificial lung. The results show for the first time in literature that the design operates within the defined requirements, based on emergency government regulations, and can be used with different sizes of resuscitator bags and different positions of the flow sensor. This provides a sound basis for further development of a low-cost, portable mechanical ventilator for potential use in LMICs.