Construction and Performance Testing of a Fast-Assembly COVID-19 (FALCON) Emergency Ventilator in a Model of Normal and Low-Pulmonary Compliance Conditions.

Luke A White,Ryan P Mackay,Giovanni F Solitro,Steven A Conrad,J Steven Alexander

doi:10.3389/fphys.2021.642353

Luke A White, Ryan P Mackay + Show 3 more

Open Access

https://doi.org/10.3389/fphys.2021.642353

Copy DOI

Abstract

IntroductionThe COVID-19 pandemic has revealed an immense, unmet and international need for available ventilators. Both clinical and engineering groups around the globe have responded through the development of “homemade” or do-it-yourself (DIY) ventilators. Several designs have been prototyped, tested, and shared over the internet. However, many open source DIY ventilators require extensive familiarity with microcontroller programming and electronics assembly, which many healthcare providers may lack. In light of this, we designed and bench tested a low-cost, pressure-controlled mechanical ventilator that is “plug and play” by design, where no end-user microcontroller programming is required. This Fast-AssembLy COVID-Nineteen (FALCON) emergency prototype ventilator can be rapidly assembled and could be readily modified and improved upon to potentially provide a ventilatory option when no other is present, especially in low- and middle-income countries.HypothesisWe anticipated that a minimal component prototype ventilator could be easily assembled that could reproduce pressure/flow waveforms and tidal volumes similar to a hospital grade ventilator (Engström CarestationTM).Materials and MethodsWe benched-tested our prototype ventilator using an artificial test lung under 36 test conditions with varying respiratory rates, peak inspiratory pressures (PIP), positive end expiratory pressures (PEEP), and artificial lung compliances. Pressure and flow waveforms were recorded, and tidal volumes calculated with prototype ventilator performance compared to a hospital-grade ventilator (Engström CarestationTM) under identical test conditions.ResultsPressure and flow waveforms produced by the prototype ventilator were highly similar to the CarestationTM. The ventilator generated consistent PIP/PEEP, with tidal volume ranges similar to the CarestationTM. The FALCON prototype was tested continuously for a 5-day period without failure or significant changes in delivered PIP/PEEP.ConclusionThe FALCON prototype ventilator is an inexpensive and easily-assembled “plug and play” emergency ventilator design. The FALCON ventilator is currently a non-certified prototype that, following further appropriate validation and testing, might eventually be used as a life-saving emergency device in extraordinary circumstances when more sophisticated forms of ventilation are unavailable.

Highlights

The COVID-19 pandemic has revealed an immense, unmet and international need for available ventilators
The use of programmable microcontrollers such as “Arduino” or “Raspberry Pi” and peripheral input devices necessitating the development and use of specialized coding or programming was deliberately avoided. Even within such constraints, the prototype ventilator should maintain adequate functionality sufficient for emergency use; in particular, the control and setting of PIP, PEEP, respiratory rate (RR), and inspiratory: expiratory (I:E) ratio. Based on this simplified design strategy, we developed and assembled a prototype ventilator (Figure 1A) which was installed in a 3D printed housing (STL printing files available upon request) using computer aided design software (Fusion 360, Autodesk, San Rafael, CA, United States) and 3D printed (TAZ Workhorse; Lulzbot, Fargo, ND, United States) using polylactic acid filament (2.85 mm PLA+; eSUN R, Shenzhen, China)
The pressure and flow waveforms generated during the ten consecutive respiratory cycles were highly uniform during each benchtop test for both the Fast-AssembLy COVIDNineteen (FALCON) prototype and CarestationTM (Figure 4 shows representative waveforms and Supplementary Figure 1 shows waveforms generated during all 36 test conditions)

Summary

Introduction

The COVID-19 pandemic has revealed an immense, unmet and international need for available ventilators. We designed and bench tested a low-cost, pressure-controlled mechanical ventilator that is “plug and play” by design, where no end-user microcontroller programming is required. This Fast-AssembLy COVIDNineteen (FALCON) emergency prototype ventilator can be rapidly assembled and could be readily modified and improved upon to potentially provide a ventilatory option when no other is present, especially in low- and middle-income countries. Support groups around the world rapidly responded by developing low-cost “homemade” mechanical ventilators for use in emergency surge crisis situations such as the COVID-19 pandemic (Albert et al, 2020; Blacker et al, 2020; Galbialta et al, 2020; Garmendia et al, 2020; King et al, 2020; Pearce, 2020; Zuckerberg et al, 2020; MIT Emergency Ventilator, 2020a)

Methods

Results

Conclusion