Specifications for a Pandemic Ventilator for Coronaviris COVID-19

Someone mentioned the BARDA specifications in one of the comments.  I was not familiar with that so I checked it out and they are specifications for a solicitation for a ventilator to be stockpiled that could be used for a mass casualty or all-hazards event, but specifically for a pandemic influenza outbreak.
The link to the HHS solicitation is here:

I took the liberty of adapting these specifications somewhat, considering that the COVID-19 outbreak is not dangerous for children and I also eliminated references to cost and replaced them with parts availability and ability of the design to be replicated and modified as needed.

Here is my list:

• Be able to be constructed by readily available components
• A filtration device to reduce or prevent the spread of virus into the air
• Only needs to accommodate adults.  Critical illness in children in this pandemic is rare and any cases that do arise can be accommodated by reallocation of existing commercial devices.
• Intuitive user interface for ease of use so that inexperienced health care providers with limited or no respiratory support training, can safely and easily use the device.
• Weight and size is a minor issue at this point.
• Closed-loop inspiratory pressure control system that can operate with minimal time and attention from staff.
• Accommodate breathing circuits and with universal connectors appropriate to patient population.
• Adequate shielding for radio frequency interference (RFI), electromagnetic interference (EMI), and conductive interference, such as a power surge, and must be demonstrated and tested in appropriate environments.
• Open source, well documented software that can be modified to easily use alternative processors, blowers and sensors
• Real time integrated O2 and CO2 monitoring may be optional as these could possibly be also accomplished with stand-alone devices, but respiratory rate is not
• Parts list and repair and troubleshooting manual
• Easily recognizable and operational audible and visible alarm systems
• Accommodate a heat and moisture exchanger (HME) or humidifier.

Meet an evaluation testing program(s) and other testing:

·         Operational, usability, and functional performance tests for adult patient populations.

·         Electromagnetic (EMI), radio-frequency (RFI) and conductive interference testing

·         Review of executed software validation protocols.

·         Usability performance for ease of use and set up type testing for inexperienced health care providers with limited or no respiratory support training and outlines all recommended characteristics and specifications incorporated into the design of the ventilator.

·         Full functional testing of the ventilator.

·         Functional testing in a clinical environment in all modes of operation under simulated use conditions in the simulated environment in which the device is expected to be used by inexperienced health care providers with limited or no respiratory support training.

·         Testing in a non-clinical environment for ease of set up and performance,

·         Differentiation of audible and visible alarm failure modes .

Other Resources for Specifications and testing:

·         ASTM F 1100-90 (Standard Specifications for Ventilators Intended for Use in Critical Care),

·         ASTM F 1246-91 (Standard Specification for Electrically Powered Home Care Ventilators, Part 1-Positive-Pressure Ventilators and Ventilator Circuits)

·         IEC 6061-2-12(Standard for Critical Care Ventilators).

Is there anything I should add or leave out?

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In my last post I assumed that most developed countries would have similar ratios of ventilators to population.  Then I wondered if any of these  BARDA HHS ventilators have actually been deployed.  I found a recent source of ventilator numbers in the

Cladex Ventilator Fact Sheet. 

from May 3, 2018, and here are their numbers:

865,000 US residents would be hospitalized during a moderate pandemic (as in 1957 and 1968) 

64,875 would need mechanical ventilation

9.9 million during a severe pandemic (as in 1918).       

742,500 would need mechanical ventilation

US acute care hospitals own approximately 62,000 full-feature mechanical ventilators.   

28,883 of these ventilators (46.4%) can be used to ventilate pediatric and neonatal patients. 

an additional 98,000 ventilators that are not full-featured but can still provide basic function.

Based on these numbers, the maximum number that can be potentially ventilated is around 160,000.

The US has 20.5 ICU beds with mechanical ventilation capability per 100,000 population

Canada has 8.7 ICU beds with mechanical ventilation capability per 100,000 population

Australia & New Zealand have only 5.4 ICU beds with mechanical ventilation capability per 100,000 population

In addition, the CDC Strategic National Stockpile has an estimated 8,900 ventilators as of 2010. 

Ventilators are stored and kept as managed inventory.

Various other factors constrain the capacity of the US healthcare system from providing ventilation therapy. Using mathematical models, one study found that the limiting factor during a pandemic-level crisis would be the number of respiratory therapists—maxing our ventilator therapy capacity at around 135,000—significantly lower than the estimated 742,500 needed

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Here is some information for Canada
Ontario has released a document Ontario’s Critical Care Ventilator Stockpile September 2019
It states that Ontario has 209 additional ventilators stockpiled, 50 of which are for neonates
This would be somewhere around 15% surge capacity

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If you want to know which ventilator designs to emulate when designing a pandemic ventilator in order to make it easy for staff to learn and use the device, this paper published by the CDC

Stockpiling Ventilators for Influenza Pandemics

gives some very useful info for stockpiling of ventilators for a pandemic.
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Here is a really interesting article from National Geographic
U.S.has only a fraction of the medical supplies it needs to combat coronavirus

Here are some excerpts:

“In a severe pandemic, we certainly could run out of ventilators, but a hospital could just as soon run out of respiratory therapists who normally operate these devices,” says Toner. The Bureau of Labor Statistics estimates that the U.S. employs 134,000 respiratory specialists, or approximately 20 of these technicians for every hospital in America.

The actual demand and supply for health care equipment during this outbreak will depend on myriad variables, one of which is an outbreak’s attack rate. As of this moment, that is a mystery for COVID-19.

The attack rate is what percentage of a population catches an infectious disease overall. If a hundred people live in a city, and a virus’ attack rate is 20 percent, then 20 citizens would be expected to get sick. Both the CDC papers and Toner’s models rely on attack rates ranging from 20 to 30 percent, a standard estimate for severe pandemics.