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 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 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.

Design and Analysis of a Low-Cost Electronically Controlled Mobile Ventilator, Incorporating Mechanized AMBU Bag, for Patients during COVID-19 Pandemic

“…As per the International norms, these designs are validated with the use of certified test lungs extended period of time [ 56 ]. Du Pasquier et al discussed the work of a novel design of a ventilator of affordable cost on the basis of automatic compression of a resuscitator bag [ 48 ]. The device is made of widely available parts.…”

“…The device is made of widely available parts. The control process of the device is to give continuous mandatory ventilation (CMV) and spontaneous breathing assistance [ 48 ]. Also, Chatburn and Mireles-Cabodevila deliberated the method of interaction between the ventilator and the human subject [ 57 ].…”

“…Mechanization of AMBU bag unit has been pursued by many researchers across the world using various mechanisms such as cam-and-follower [ 47 ], slider-crank [ 49 , 50 ], rack and pinion [ 51 ], dual-cam [ 54 ], and several complex kinematic and pneumatic systems [ 48 , 52 , 53 ] leading to a number of patents and effectivity analyses. In most of these mechanisms, the AMBU bag is subjected to nonuniform clamping force as being pressed between one moving clamp and one fixed clamp.…”

Testing of pandemic ventilators under early and agile development

“…In this study, the protocol was applied for testing three novel PDVs and one clinical approved ventilator as reference: the GirVent (Girtec AG, Nänikon, Switzerland), the High Energy Ventilator (HEV, CERN, Geneva, Switzerland) ( 8 ), and the breathe (ETH, Zurich, Switzerland) ( 9 ). The three PDVs selected represent the three different most commonly used functional principles.…”