Back storyThe story of our effort to help hospitals that need ventilators.
This project began on March 16, 2020, when Dr. William Whetstone contacted Dr. Thomas Greany, stating that conditions looked grim regarding current forecasts of COVID-19 cases in the San Francisco Bay area. In addition, that a nationwide shortage of ventilators was anticipated. Whetstone asked Greany whether he thought a field ventilator could be designed and built quickly to provide basic respiratory support for multiple patients to prevent a situation of having to deny any person rescue ventilation in the event of a shortage of FDA approved hospital ventilators.
Dr. Whetstone is a CU-trained engineer, currently a Clinical Professor of Emergency Medicine at UCSF; and an emergency physician at San Francisco General Hospital. He completed his medical degree at the University of Colorado Health Sciences Center and his Emergency Medicine residency at the University of Michigan. Dr. Greany is a CU-trained engineer/dentist and Assistant Professor at CU’s Anschutz Medical Campus. He has practiced as an engineer and dentist most of his career.
Fifteen days after the initial conversation took place, Greany delivered a prototype unit (1:1 I/E respiration mode only) to Whetstone in San Francisco. On April 1, the unit successfully demonstrated simultaneous, asynchronous 1:1 I/E air flow to two manifolds of four patient ventilator ports each (eight total). Dr. Whetstone recommended an additional 1:2 I/E ventilation mode be added if possible. Greany modified the design the same day to include this new mode, introducing the need for a second digital relay timer and solenoid valve (this design was later simplified through the use of a more sophisticated programmable logic controller- see the Rev 2 notes). The 1:2 I/E model allowed for addition of a third manifold of four patients (twelve total).
The following day, in response to new data received from UCSF regarding evolving COVID-19 protocols, a method of rapidly converting from 1:2 I/E to CPAP mode was configured. CPAP mode does not require valves or logical timers, and may be useful for patients in avoiding non-invasive ventilation. Finally, a method of integrating 100% oxygen from stationary hospital-supplied, or portable tanks was configured, which can improve outcomes for patients whose inflamed lungs cannot efficiently accomplish respiratory function. Low flow (~2.5 Liters per minute) CPAP can be delivered to eight patients simultaneously via the prototype unit with a quick tubing re-route through normally open solenoid valves. If done, oxygen cleaned solenoid valves should be substituted for those used in the prototype. Depending on the availability of 100% oxygen under field conditions, higher flow can be delivered to additional patients. For CPAP mode on the prototype, valve timing is disabled.
This site documents the design of Dr. Greany’s resulting three-mode field ventilator Prototype; as well as the subsequent Rev 2 modifications which added respiratory modes; enhanced safety; improved reliability; and added flexibility for extended continuous duty service life. Rev 2 modifications were made in collaboration with an outstanding RK Mission Critical team in Aurora, Colorado; and six Rev 2 Field Ventilators were built in their facilities.
Either revision of the ventilator can supply simultaneous rescue ventilation for up to 12 patients at variable flow rates to accommodate individual tidal volume needs, although Rev 2 would certainly recommended for its improved safety; respiratory mode flexibility; and anticipated service life. The site also provides plans for building, operating, and troubleshooting the prototype units. Manual operation of flow distribution in the event of solenoid failure as presented for the prototype has been eliminated in Rev 2. This is because the Rev 2 solenoids are anticipated to have a much greater service life than those used in the prototype. Photos and videos documenting the Rev2 build are supplied; however the Rev2 power module and programming will require approval by and interaction with the authors of this site.
Please note: this emergency field ventilator is not intended to replace clinically validated FDA-approved traditional hospital ventilators, which provide additional flexibility, monitoring and user interface improvements. Nor should this site be construed as an authorization or recommendation to use the field ventilator device in clinical applications. The decision to do so rests entirely with physicians supervising the care of the patients.
Dr. Greany, Dr. Whetstone and the RK Mission Critical team acknowledge that design refinements are certainly possible beyond Rev 2. Individual component and system longevity cannot be estimated or extrapolated from short term testing; nor can clinical performance of the device or patient outcomes be predicted. But with little time to prepare for the possibility of a nationwide shortage of ventilators, this device may provide emergency ventilation to patients who may otherwise receive nothing. The primary purpose of this website is to enable others to innovate and improve based on this multi-patient design with the hope of helping to save lives. It is further hoped that the design may provide a basis for patient ventilation at a reasonable cost in developing countries, where ventilators may not be available. Such derivative works will be based on extensive feedback and testing from the medical community.
The rapid design, build, and deployment of this project could not have been accomplished without the technical input and support of multiple ER physicians and respiratory therapists in Colorado and California. Ken Lambrecht (another CU-trained engineer) also helped Greany brainstorm, assisted in the documentation of this project, and created this website. Thanks to Haidar Malhas, a hydraulics engineer living in Ghana for input on pressure relief. The leadership, planning, supply chain, technical and build teams at RK Mission Critical have been extraordinary in their individual roles.
Our hope is that the critical national shortage of rescue ventilators identified during the COVID-19 pandemic, which exposes a strategic vulnerability; as well as the realization that developing nations have no ventilators at all will find a potential solution in this Field Ventilator device. Through testing and refinement, we hope that this device will provide a real solution that can be readily produced at reasonable cost.
Finally, a special thanks to all of the ER physicians, nurses, respiratory therapists and other health staff who are putting themselves in harm’s way every day to provide critical care to those suffering from the COVID-19 virus.
Thank you to everyone involved in helping out during this crisis!
The content on this website is being released in this manner to maximize the potential public benefit during this urgent need for measures to respond to the COVID-19 crisis, including promoting potential ventilator manufacturing methods.
The content has not been reviewed or approved by the U.S. Food and Drug Administration (FDA). Interested readers are encouraged to contact the FDA and review available FDA materials, including their guidance on ventilators as well as the Department of Health and Human Services (DHHS) declaration of liability immunity for medical countermeasures against COVID-19.
PLEASE NOTE: The content has not been peer reviewed. The Authors make no representations or warranties of any kind (express or implied) relating to accuracy, safety, usefulness, usability, marketability, performance, or otherwise of the content released here. The Authors disclaim all express and implied warranties of merchantability and fitness of the content for a particular purpose, and disclaims all express and implied warranties regarding non-infringement of any patent, copyright, trademark, or other rights of third parties in the content or use of the content, or in the making, using, or selling products or services by any person or entity.
People or entities attempting to use the content in any way, including creating products or offering services, assume all risk and responsibility related to those uses, including all legal and regulatory compliance, safety, efficacy, performance, design, marketability, title, and quality. The Authors assume no liability related to the actions of third parties and in respect of any infringement of any patent, copyright, or other right of third parties.
The content has not been used in testing with humans at this time.
The Authors’ names and logos are trademarks or other exclusive property of the Authors. Readers of the content shall not use the name or logo of any Author in any way for publicity, advertising, or other commercial purposes, including linked to the reader’s products or services. Readers of the content shall not make statements or representations that, in Author’s sole judgment, deliberately or inadvertently claim, suggest, or give the appearance or impression of a relationship with or endorsement by that Author.
The Authors are proud of their affiliation with the University of Colorado as alumni and, in the case of Dr. Thomas Greany, as a professor at the Anschutz Medical Campus. The Authors express their appreciation to the University of Colorado for its support of this project.