COVID Ventilators

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  1. 3/24/20 - FDA defines mitigation strategy


  • 2010 survey reported U.S. hospitals had 62,188 full-featured mechanical ventilators on hand, but the numbers varied widely by state - [1]
  • Doctors decide selection criteria for allocating limited medical equipment - [2]. Sadly - “This is a shift to caring for the population, where you look at the whole population of people who need care and make a determination about who is most likely to survive, and you provide care to them,” she said. “Those that have a less good chance of survival — but still have a chance — you do not provide care to them, which guarantees their death.”
  • Most severe cases require ICU care, of which there are 200k beds in the USA.
  • The Johns Hopkins Center for Health Security estimates that 38 million Americans will need medical care for COVID-19, including as many as 9.6 million who will need to be hospitalized – about a third of whom might need ICU-level care. In a February presentation to the American Hospital Association, Lawler estimated that as many as 96 million Americans could be infected. - from ''


  1. MIT List of ventilator projects - [3]
  2. Polish version - [4]
  3. Y Combinator - open discussion - [5]
  4. Vice - [6]
  5. Global ventilator hackathon and need for EMTs & Firefighters - [7]
  7. 1 Million Ventilators - is this an open source project?
  8. See other efforts at [8]
  9. Incentive challenge at Ennomotive - [9]
  10. Other efforts listed by Ennomotive - [10]
  11. Ifixit - repair manuals crowdsourcing - [11]
  12. TPU 3D Printed mask - [12]

Designs, Prior Art, Patents, Industry Standards

  1. Manley ventilator explained, 1960 design - [13]
  4. Bag Valve Mask ventilator - Gitlab - [14]
  5. Brescia design - [15]


  • Ventilator specialist Ventec. GM Collaborating with Ventec?

DARPA Request

From: Vandenbrande, Jan <> Sent: Thursday, March 19, 2020 8:31 PM To: Vandenbrande, Jan <> Subject: I may need your help to build ventilators


As you are probably aware, the president of the US has initiated the Defense Production Act which gives priority to the production of equipment of national safety in response to the current corona virus pandemic. I have been tasked to understand what we can do to ramp up production of ventilators, leveraging additive manufacturing at scale and idle manufacturing plants. The US may need an additional 10,000-100,000 ventilators in a couple of weeks, though other predictions indicate we may need more (750,000).

I am still in the process of understanding what the bottlenecks are, but would like to initiate your thinking processes on what you could possible contribute after you familiarize yourself with ventilator design. Here is a UK link that gives some ideas of the specs:

If you are already engaged in some way, let me know. Lots of efforts are underway, but they may not be enough. I am open to accelerating production of existing devices but also open to old designs/open source/off-the-shelf (e.g., Arduino, robot components) that we can build quickly. Demand will not be met with a single solution.

At this point this is just a heads up email. I hope to have more details in the next 24 hours after I talk to a couple OEMs. But if you have clever ideas, who I should talk to in your organization or others, let me know. Feel free to propagate this email.


BCC’ed to DARPA contractors on my programs, past collaborators and other clever people.

Jan Vandenbrande - Program Manager - DARPA Sciences Office - (571) 218 4553

UK Ventilator Spec


There is a detailed list of requirements on the application form itself, with a quick overview noted below. The RMVS must…

Be reliable. It must work continuously without failure (100% duty cycle) for blocks of 14days — 24 hours a day. If necessary, the machine may be replaced after each block of 14 days x 24 hours a day use.

Provide at least two settings for volume of air/air O2 mix delivered per cycle/breath. These settings to be 450ml +/- 10ml per breath and 350ml +/- 10ml per breath.

Provide this air/air O2 mix at a peak pressure of 350 mm H2O.

Have the capability for patient supply pipework to remain pressurised at all times to 150mm H20.

Have an adjustable rate of between 12 and 20 cycles/breaths per minute.

Deliver at least 400ml of air/air 02 mix in no more than 1.5 seconds. The ability to change the rate at which air is pushed into the patient is desirable but not essential.

Be built from O2 safe components to avoid the risk of fire and demonstrate avoidance of hot spots.

Be capable of breathing for an unconscious patient who is unable to breathe for his or herself. Ability to sense when a patient is breathing, and support that breathing is desirable but not essential.

Be able to supply pure air and air O2 mix at a range of concentrations including at least 50% and 100% Oxygen. Oxygen shortages are not expected, but the ability to attach a Commercial Off The Shelf (COTS) portable O2 concentrator machine may be a useful feature.

Support connections for hospital Oxygen supplies — whether driven by piped or cylinder infrastructure

Be compatible with standard COTS catheter mount fittings (15mm Male 22mm Female)

Fail SAFE, ideally generating a clear alarm on failure. Failure modes to be alarmed include (but are not limited to) pressure loss and O2 loss

[Click here], for more information and to apply. Legal - [16]


Foul Play

  • Lacking right of repair - [18]

Canada Challenge

  • $200k prize for ventilator - [19]


  • HEPA filters filter 100 nanometer particles effectively, with H13 and H14 grade filters - [20]. These are more effective than N95 masks.
  • HEPA filters are made either of borosilicate glass or PP -[21].
  • HEPA fibers are 0.5-2 microns. [22] Human hair - 17-50 microns - [23]

PAPR vs N95

  • Both require training.
  • PAPR disadvantages - Their disadvantages include difficulties in communicating due to their bulk and noise, the inability to use a stethoscope and a requirement for electricity (batteries) to ensure proper airflow rates into the hood. After use, filters are considered to be contaminated with infectious material; therefore, they pose a potential risk to individuals reprocessing reusable respirators - [24]
  • The decision to use a PAPR for aerosol-generating procedures (AGPs) without a program in place can lead to more self-contaminations than using appropriate PPE with a fit-tested N95 mask. - Ie, you must be trained to PAPR
  • PAPR is more effective than N95 disposable mask [25]

Are Ventilators Needed?

  • Most transmission occurs from germs landed on surfaces, but aerosols and droplets also contain the virus
  • Thus, someone who sneezes on you can transfer the virus to you
  • Why are face masks not recommended, then? Because touching one's mouth or eyes is a much greater probability? What is the ratio for surface transmission vs aerial transmission? 10000:1? 10:1?
  • See transmission via aerosols - [26]
  • Can live in air for up to 3 hours? [27]
  • Yes, up to 3 hours in air. “You would need to touch contaminated secretions to become infected, or to be within six feet of a sick person who is coughing or sneezing [28]