Simple Ventilators for Emergency Use Based on Bag-Valve Pressing Systems: Lessons Learned and Future Steps
, Cornelius Mach 2, Goretti Hernandez-Cardoso 1, Bhushan Savalia 2, Jochen Taiber 2, Armando Ruiz-Marquez 1, Karl Kesper 3, Srumika Konde 2, Caroline Sommer 2, Julian Wiener 2, David Geisel 2, Franziska Hüppe 2, Gunter Kräling 4, Peter Mross 5, Johnny Nguyen 2, Thomas Wiesmann 6, Björn Beutel 7,8 and Martin Koch 2Round 1
Reviewer 1 Report
Thank you very much for the opportunity to review you paper entitled "Simple ventilators for emergency use based on Bag-Valve pressing systems: Lessons learned and future steps." Given the pandemic, this topic of significant interest and there are many variations of the design for bag valve pressing systems. A couple minor points to consider:
- How is tidal volume assessed in a real patient using this simple bag valve pressing system. Certainly it can be titrated up and down, but is there any mechanism by which one can measure tidal volume in an intubated patient? Certainly in a subgroup of COVID-19 patient populations, ensuring true lung protect ventilation may be important.
- What safety mechanisms are in place to detect disconnects, leaks in the circuit, etc?
- How does your system detect vent dyssynchrony?
- As the patient's lung's compliance change, how will your tidal volumes change?
- Is this system ideal for patients who do not require lung protective ventilation?
- How does this system deliver pressure support and detect patient breaths? What additional sensors are necessary so that the eARM system can do this?
- What are the barriers that should be addressed to move this from proof of principle to reality?
- How is this design better/different than the other designs for bag valve pressing systems (ie. the MIT group published in Intensive Care Medicine)?
Author Response
Please see attachment
Author Response File: 
Author Response.pdf
Reviewer 2 Report
In this work by Castro-Camus et al. the researchers provided mechanical design proof-of concepts for two ventilator systems claiming they are beneficial for dealing with COVID-19 pandemic. This work seems to be neither an original article nor a review article; seems like somewhere in between to me. The authors focused on the mechanical designing of new kinds of ventilator systems which looks like a mere proof-of-concept to me. This work lacks clear experimental evidence and whether these designs will find a place in the market will depend a lot on clinical trials. Therefore, I do not find any significant immediate impact of this work related to the global pandemic. Besides, I agree that the ventilators are playing an important role in battling this global health pandemic, however, I am skeptical about how these new designs are better compared the existing ventilator systems apart from being low cost. A Table comparing the pros and cons of the proposed two ventilator system set-ups and the existing ventilator systems (commercially available or under FDA-approval process) is missing. The article contains only schematic of the microcontrollers and the system set-up without actual evidence of how the real-time system looks like. This works seems like the authors tried to provide a proof-of-concept of a system without taking into consideration long term plans. As the mechanical designs seem promising, I can recommend for publication only after several rounds of brainstorming thought processes from the author’s part on the afore-mentioned comments.
Author Response
Please see attachment
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
The authors have taken the reviewer's comments quiet seriously and I do recommend publication at this stage of the manuscript.
