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* Automated Ambubag device controlled by a pi 4 and actuated by two NEMA 17 stepper motors
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* Touch screen interface
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* Structure is entirely 3D printed
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* Parts cost is currently ~$150
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![Capture](uploads/8d6d16c0fe9c0196a9f34170c1543b9c/Capture.PNG)
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... | ... | @@ -34,7 +35,6 @@ This project, both hardware and software, is available to all for use without re |
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[LCAEV-0.1-parts.zip](uploads/5fba291c5bb63026536299bb34f95456/LCAEV-0.1-parts.zip)
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### Non-Printed Components
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* 1x Raspberry Pi 4 (any version)
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* https://www.amazon.com/Raspberry-Model-2019-Quad-Bluetooth/dp/B07TD42S27/
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... | ... | @@ -89,184 +89,19 @@ This project, both hardware and software, is available to all for use without re |
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# Research
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Research captured here:
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[[Ventilator Research]]
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## Current Ventilation Methods
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* Invasive
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* Noninvasive
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* Cuirass
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* Continuous Positive Sirway Pressure (CPAP):
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* cannula?
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## Ventilation Modes
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* Assist Control (AC): driven by patient on top of set rate, constant volume
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* Synchronized Intermittent Mandatory Ventilation (SIMV): same as AC, but variable volume depending on patient draw
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* Pressure Support: driven by patient, provides extra pressure, but nothing that's not triggered and no set volumes (last step before extubation)
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## Notes on Ventilation
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* typical respiratory rate: 8-20 breaths per minute
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* the compliance of lungs can vary over time, so pressure needs to be monitored
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* You dont want to exceed a peak inspiratory pressure over 50cmh2o. A mean airway pressure over 30cmh2o. Or a plateau pressure over 30cmh20. The pressures needed vary on lung compliance(stiffness of lungs). So in order to maintain flow varying pressures are needed.
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* Random from the slack
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* Of all our projects: Go hard with Ventilators. They WILL be used.
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* Strength of Ventilators (vs just a volunteer/nurse with Ambubag) is maintaining a stable precise PEEP (and other params) - almost impossible with just an Ambubag. The automation (and precise control) helps a lot.
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* Manometer (pressure sensor) is only thing they really need with ventilators - and they may have a lot more in stock than ventilators (he doesn't know but suspects), so may not even need to manufacture these
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* C02 censors aren't really needed - they have enough ways to do that already. (daily blood tests are done already anyway)
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* Ventilator supply vs doctor time/expertise supply: bottleneck is ventilators. They WILL be used. Intubation time/patient care is no big deal compared to not having the ventilator.
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* more
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```
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Hi all, I'm an anaesthetist and ICU doctor from the UK. I love all the enthusiasm but wanted to share this across several groups as I think we should be focusing on the reason I joined this group in the first place which was to create plans for a simple mass producible ventilator.
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Basically what we need for covid are plans for mass producible invasive ventilators that can supply high concentration 02 from hospital supplies with high levels of peep (up to 20cmh20). If these can be at least partially 3d printed then all the better.
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Hospitals will take whatever they can get once it gets bad and in the UK alone we are going to need 1000s of new ventilators. If it works then there will be a place for it. Yes staffing will be an issue, but we are expecting to adapt and stretch existing personnel. We can't do this without the right hardware however. 02 supply in many hospitals also far outstrips the available ventilator supply at present.
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Ideally any device would be simple, robust and mechanical (minimal electronics). Covid patients are not difficult to ventilate so any ventilator types/modes would work but they do need peep and high 02 as oxygenation is the problem. We don't need anything near as sophisticated as current ICU vents for the majority of patients.
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Otherwise vents could be pressure or flow limited with time or volume cycling. Normal vent settings are rates of 10-25bpm, inspiratory: expiratory ratio of 1:2, volumes of 200-600ml and max inspiratory pressures of 30-40cmh20, with peep up to 20cmh20. Supply pipeline pressures are 440kpa for 02 and air, with tubing needing to fit 15/22mm connectors.
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Hope that makes sense. If you are able to disseminate these requirements to as many people in the groups with relevant skills or experience that would be really helpful. Thank you for taking part in this and for your enthusiasm to help!
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```
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* even more
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Research captured here: [[Ventilator Research]]
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```
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Q: [Told him about the various projects we're looking at, and asked what would be most useful to him]
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A: Ventilators. All the way.
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Q: Yeah? You'll use them even if they're DIY?
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A: we can say now that we won't use them, but when the choice is to let grandma die or try the diy ventilator, the choice seems clear to me. a lot of things are going to change dramatically very soon.
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Q: How are you for Ambubag - will those run out? Lotta designs making automated squeezers for those with sensors
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A: Yes. Ambubags are less of a concern as far as I know, but there may come a time when we need a few hundred volunteers to come in and pump the bags day and night until recovery, if there are no ventilators. My one hope for this front is that someday soon there will be a large contingent of people recovering from this virus who are then immune and can start helping run the hospitals etc
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Q: What's the big gain of a ventilator vs Ambubag for you? Both can do PEEP with the Ambubag valve, yes? Or are those in shortage too?
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A: PEEP would be almost impossible to control with an ambubag
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Q: Interesting. Why - lack of sensors of patient lung pressure?
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A: Exactly. You'd have to control the pressure yourself. By hand. You'd struggle mightily to keep a constant peep by hand. That is the advantage of ventilators - every parameter can be precisely controlled, and you can decicide which parameter to use as the dominant factor in the ventilatory pathway.
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Is it important to always have a tidal volume of 500ml or is it preferable to use pressure control so that the lung tissue never experiences pressure >25mmhg despite lower tidal volumes - for example
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Q: PEEP, tidal volume, rate, o2% - any more?
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A: expiratory time. though that one is more for specialized situations where lung compliance/chest wall compliance is at issue. COPD, trauma - not important for covid. Most of those patients if not all have normal lungs at baseline
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Q: What's the biggest nuisance factor to doctor time?
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A: definitely charting. then applying PPE
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Q: Can we help there? how's charting go?
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A: Actually, scribes would probably help quite a bit there. recording your assessments and the plan for each patient. by hand, usually in great detail, for every single patient - every single day...
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Q: Would you assume that will possibly fall by the wayside very soon, as paperwork becomes less important than doctor time?
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A: sadly, it actually is important. As teams change and new staff comes in having good documentation really is important. To understand why each decision was made etc. But it will certainly be streamlined.
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Q: If we had an app that tracked the patient's info + ventilator data + whatever, would that just add to the noise or help?
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A: Those already exist. they just spent a billion dollars implementing one on [Vancouver island] - aaaaaaand nobody can figure out how to use it.
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Q: what if e.g. there was simply an app just for coronavirus patients?
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A: it probably would help... the issue would be getting it to dovetail with current systems, and teaching people to use it.
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The one nice thing with the coronavirus patients is that their management is actually quite simple - until they go to the ICU: apply oxygen. You could almost automate tx for patients with moderate disease: put on the face mask and oxygen sat monitor and have it self titrate to O2 sat > 93%
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Q: Do you guys apply oxygen because its the best treatment for mild caes, or becaue the risk of aerosoled virus from ventilators is too high unless they really need it - in which case they go to the ICU?
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A: best treatment. intubation actually prevents 98% of resp droplets and almost renders a patient non-infectious (well, if the intubated person is on a vent) because their breath just goes into the machine and not into the world at large. if you're bagging them then that's a whole different kettle of fish
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Q: Alright good. so it wouldn't change that part if there were more ICU-like beds (e.g. if we could make triage negative pressure rooms)
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A: yes
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Q: Vent sensors: is lung pressure (manometer) sufficient? Do you need blood CO2 tracking too? Or is that a nice to have?
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A: Nah, they can track blood CO2 levels through a variety of external monitors, blood tests. which they'll do daily anyway in the ICU. definitely the manometer is needed though
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Q: Will manometers run out? same rate as vents?
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A: Not sure to be honest. Not in the hospital much at the moment. But certainly manometers would be easier to get a hold of than full vents
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Q: If you guys somehow had a lot more ventilators, would they all still get used - or is the intubation and care such a pain that the real bottleneck is doctors/expertise?
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A: definitely they'd get used. intubation takes like 10 minutes, and could be done one after another if need be
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```
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* moar
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```
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UK Government (Michael Gove) is sharing now their Need for Manufacturing new ventilators, the mechanical ventilator requirement is becoming more clear.
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The lung and chest muscles being tired, the mechanical ventilator helps get the oxygen and provide facilitator for getting oxygen to blood.
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A lot of designs have come out of articles - how long some one on a machine is 24hrs/7 days a week - total reliability is a must.
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Questions being asked/
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Q/ Do we have to produce ventilator device and ancillary equipment
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A/ Looking at the just the requirement set
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Q/ How do we get the largest number of ventilators into the system
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a/ a standard- not being too creative but up the scale quickly
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Q: O2 uptake measurement per patient
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A:
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Q: Volume control and Pressure control
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A: Both important- pressure or volume limit would need to be set - Pressure would be more important than volume if pushed
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Q: Waiver for standards for this purpose
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A: Write to us to confirm your consideration
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Q: it is a must that the machine will breathe for unconscious patient
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A: if unconscious should breath with low drive, and cope with the pressure can drive
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mandatory for unconscious drive
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Q/ Filtration and Humidification
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A/ not required - provided in a circuit within the consumable
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Q/ monitoring functions Pressure vs Time And not included in scope
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A/ need to decide - how much is going into the patient and what is coming out, focus on the black box of ventilator
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Q/ Oxygen supplies
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A/ making device more efficient for use of oxygen
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Q: what are you looking for full devices or components
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A: looking for both component and full devices
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Q/ License or build to print
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A/ established ventilator devices are incredibly complex against the spec set out, looking at learning from them and sharing
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Q/ where are we in ordering components
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A/ as designs emerge - we need to secure a supply chain with match maker service in Government
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Q/ standard of equipment
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A/ will be published
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Normal rules of business don’t apply - as many safe and effective ventilators and help rather than hinder- can we preauthorise devices
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Q/ is there a range of PPE for aviola collapse?
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A/
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Q/ have you considered establishing a Project Management team
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A/ PA consulting and BEIS coordination
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Q/ Units required
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A/ working on assumptions of 20,000 devices in the Health System
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if more produced they will be used subject to MSRA guidance
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Don’t worry about over producing
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Bill of materials 50-60 items
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Assembly and design for manufacturing
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Selection in 2 days for final design - down select Wednesday
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```
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* moreee
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* [Mar_16_2020_Cabahug_ChongHuaHospital_EmergencyRequest_.pdf](uploads/a9da890ddc699eeb099c445378164ca3/Mar_16_2020_Cabahug_ChongHuaHospital_EmergencyRequest_.pdf)
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## Path forward
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Ideal to do something noninvasive as invasive requires anesthesia.
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Requirements
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* cheap (as cheap as you can, certainly sub $1k)
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* parts easily/readily available
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* easy to assemble
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* dirt simple to use
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* variable settings
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* can run for weeks
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Questions:
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* what type to use?
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# Design Log
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Progress and stumbles captured here:
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[[Design Log]]
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## Similar Efforts
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Progress and stumbles captured here: [[Design Log]]
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* OSV VBM: https://gitlab.com/TrevorSmale/OSV-OpenLung
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* Automates bag valve mask ventilators
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* still in development
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* Rice: https://www.youtube.com/watch?v=1t2t8d8xtD0&
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* Automates bag valve mask ventilators
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* MIT Umbulizer: http://news.mit.edu/2019/umbulizer-sloan-health-care-innovation-prize-0225
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* Automates bag valve mask ventilators
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* costs $2k
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* Pakistan?: http://www.technologyreview.pk/pakistani-engineer-braves-tragedy-to-develop-low-cost-ventilator/
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* Automates bag valve mask ventilators
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# Contact
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## Resources
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We would love to hear from you with your needs and/or feedback! Drop us a line at: lcaev.contact@gmail.com
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* explanation of mechanical ventilation: https://www.youtube.com/watch?v=i6hmGVBbIJk
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* flash animation of ventilator: https://www.hamilton-medical.com/.static/HAMILTON-T1/start.html
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* News article on ventilator shortage: https://abcnews.go.com/Health/demand-ventilators-spikes-coronavirus-looms/story?id=69597233
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* gas-driven ventilator: http://www.diamedica.co.uk/english/product_details.cfm?id=1561
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* FormLabs may be willing to print things
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* AtomusPrinting may be willing as well: https://www.atomusprinting.com/
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