|
Very clever, but too simple?
--
Art Greenberg
art@...
|
https://youtu.be/LJK_s3d9wQM
|
It's clever yet too simple and too complicated at the same time?
These simple fixed cycle machines would work with health lungs but not as an ARDS ICU ventilator.
I wish all the clever people and teams around the world would collaborate more on machines that would actually do the job.
I've tried to . Please have a look. I'm keen to receive review and feedback.
Erich Schulz,?mbbs, mba, fanzca 0410 277 408
On Wed, 8 Apr 2020 at 07:13, Art Greenberg < art@...> wrote: Very clever, but too simple?
--
Art Greenberg
art@...
|
This is about the only potential application I can see for a bag squeezer - a patient who is paralysed and has healthy lungs. You could never wean a patient using that kind of ventilator and that is the challenge with the Covid19 pandemic. We need to get patients in and out of ICU as fast as possible. Erich Schulz,?mbbs, mba, fanzca 0410 277 408
|
The China bag squeezer is quite ingenious with 3rd world local parts.?
A nice "bag squeezer" from Vanderbilt??
Nice DIY negative pressure Curiass ventilator effort -
https://youtu.be/pvrUQCMa3a8
|
arrrgg
so many under spec solutions!!! I took to twitter to have a little rant on the topic.
I'm really hoping that we can get all these clever teams to start collaborating.
It seems to me that so many teams are starting with underspecified MVPs.
I'm still trying to figure out what can be done about achieving the goal of inter-team collaboration. I'm not sure my twitter rant will achieve much.
Erich Schulz,?mbbs, mba, fanzca 0410 277 408
On Wed, 8 Apr 2020 at 16:38, < quad@...> wrote: The China bag squeezer is quite ingenious with 3rd world local parts.?
A nice "bag squeezer" from Vanderbilt??
Nice DIY negative pressure Curiass ventilator effort -
|
Erich, Sorry about your frustrations. This world has become too visually oriented and YouTube definitely contributed to this effect on people. While we see so many variations of mechanical AMBU (BVM) bag squeezers, most people do not understand that this type of "dumb" device is only appropriate for a short-term? ambulatory mitigation of breathing assistance. It may work well with lungs that are fully or at least mostly functional. However, due to lack of feedback from the patient's physiology and in the case of COVID-19 infection, an escalating series of defects in the lung functionality, a dumb device may kill the patient, instead of sustaining their lives. Most people are not aware that even with the most sophisticated ventilators, pulmonary knowledge-based supervision of the machine (at least setting its mode of operation) must be exercised to match the dynamics of the patient's lungs.
I believe that in his group we have people who can combine cross disciplinary knowledge to the point where we can bridge over the gaps of the functionality that must be augmented on-top of dumb air-supply devices. This augmentation must be using sensors and signal analysis to match the air delivery system to the dynamics of the patient's condition,?including CO2 exhalation levels. Modern, cheap and off the shelf electronic modules and components (sensors, actuators,microprocessors,etc.) must be used to an advantage and open source software can glue all the parts together. I agree with you that exact specifications must be used as guides to implementation. I hope that everyone on this group had read your documents. Thanks you for going to the effort of producing them.?
--Ron N7TFZ
arrrgg
so many under spec solutions!!! I took to twitter to have a little rant on the topic.
I'm really hoping that we can get all these clever teams to start collaborating.
It seems to me that so many teams are starting with underspecified MVPs.
I'm still trying to figure out what can be done about achieving the goal of inter-team collaboration. I'm not sure my twitter rant will achieve much.
Erich Schulz,?mbbs, mba, fanzca 0410 277 408
On Wed, 8 Apr 2020 at 16:38, < quad@...> wrote: The China bag squeezer is quite ingenious with 3rd world local parts.?
A nice "bag squeezer" from Vanderbilt??
Nice DIY negative pressure Curiass ventilator effort -
|
Hi there, Greetings to all heroes..?
I am a senior electrical engineer with some previous experience about car tyre nitrogen inflator systems and microcontrollers. I am new to your group and sorry if I might missed or misunderstood any e-mails..
Constructing David's? rubber exhalation valve seemed not handy for me. And an adjustable inspiratory pause is possible?only with? a controllable exhalation valve. (I 've already built a very simple 2 solenoid-valve ventilator with a compressor just?for POC purposes.? Since my? exhalation valve was 1/2 '? the airway pressure was high. I am almost about to order 1' valves although they are a little bit costy.)
And Now I am totally confused since I also noticed those increasing number of automated? AMBU (BVM bag) projects you mentioned. They seem to be a clean / complete solution with manual peep valves, over pressure protection, exhalation with a proven security.?
@Erich, @Dr.Flywheel, do you think that if we integrate pressure sensor ,O2 sensor to an automated BVM bag,? may that?correspond most of the specs of a real ventilator.
Listing UFHealth Ventilator Engineering Specs below, I am looking forward to?hear?your answers to analyse which one of specs below,? can not correspond in any circumtances?with an automated BVM bag.
Tidal Volume: Yes? (not precisely but maybe calibrated/tuned.) Respiratory Rate: Yes? I:E Ratio: Yes PEEP Valve: Yes (On the mask)
Anti-asphyxia valve: Yes? (on the mask)
Over-Pressure Valve:Yes? ?(on the mask)
Plateau pressure: (with ambu bag squeezing speed trajectory ?)
Peak pressure:(with ambu bag squeezing speed trajectory ?)
Inspiratory Pause: ? (may need a solenoid valve)
Spontaneus Breathing: ? (check valves)
In-built blender: ?
Oxygen Sensor: (Can be placed)
Thanks for your answers and for this great group.. Best Regards,
Baskan
Dr. Flywheel < Dr.Flywheel@...>, 8 Nis 2020 ?ar, 20:34 tarihinde ?unu yazd?:
Erich, Sorry about your frustrations. This world has become too visually oriented and YouTube definitely contributed to this effect on people. While we see so many variations of mechanical AMBU (BVM) bag squeezers, most people do not understand that this type of "dumb" device is only appropriate for a short-term? ambulatory mitigation of breathing assistance. It may work well with lungs that are fully or at least mostly functional. However, due to lack of feedback from the patient's physiology and in the case of COVID-19 infection, an escalating series of defects in the lung functionality, a dumb device may kill the patient, instead of sustaining their lives. Most people are not aware that even with the most sophisticated ventilators, pulmonary knowledge-based supervision of the machine (at least setting its mode of operation) must be exercised to match the dynamics of the patient's lungs.
I believe that in his group we have people who can combine cross disciplinary knowledge to the point where we can bridge over the gaps of the functionality that must be augmented on-top of dumb air-supply devices. This augmentation must be using sensors and signal analysis to match the air delivery system to the dynamics of the patient's condition,?including CO2 exhalation levels. Modern, cheap and off the shelf electronic modules and components (sensors, actuators,microprocessors,etc.) must be used to an advantage and open source software can glue all the parts together. I agree with you that exact specifications must be used as guides to implementation. I hope that everyone on this group had read your documents. Thanks you for going to the effort of producing them.?
--Ron N7TFZ
arrrgg
so many under spec solutions!!! I took to twitter to have a little rant on the topic.
I'm really hoping that we can get all these clever teams to start collaborating.
It seems to me that so many teams are starting with underspecified MVPs.
I'm still trying to figure out what can be done about achieving the goal of inter-team collaboration. I'm not sure my twitter rant will achieve much.
Erich Schulz,?mbbs, mba, fanzca 0410 277 408
On Wed, 8 Apr 2020 at 16:38, < quad@...> wrote: The China bag squeezer is quite ingenious with 3rd world local parts.?
A nice "bag squeezer" from Vanderbilt??
Nice DIY negative pressure Curiass ventilator effort -
|
Thanks Ron - I am feeling much better after my little rant.
The documents are very much living so I would welcome review and contributions (for example links to resources and discussion around individual components) - I am particularly hoping that the may be useful for facilitating sharing of knowledge between groups.
Erich Schulz,?mbbs, mba, fanzca 0410 277 408
Erich, Sorry about your frustrations. This world has become too visually oriented and YouTube definitely contributed to this effect on people. While we see so many variations of mechanical AMBU (BVM) bag squeezers, most people do not understand that this type of "dumb" device is only appropriate for a short-term? ambulatory mitigation of breathing assistance. It may work well with lungs that are fully or at least mostly functional. However, due to lack of feedback from the patient's physiology and in the case of COVID-19 infection, an escalating series of defects in the lung functionality, a dumb device may kill the patient, instead of sustaining their lives. Most people are not aware that even with the most sophisticated ventilators, pulmonary knowledge-based supervision of the machine (at least setting its mode of operation) must be exercised to match the dynamics of the patient's lungs.
I believe that in his group we have people who can combine cross disciplinary knowledge to the point where we can bridge over the gaps of the functionality that must be augmented on-top of dumb air-supply devices. This augmentation must be using sensors and signal analysis to match the air delivery system to the dynamics of the patient's condition,?including CO2 exhalation levels. Modern, cheap and off the shelf electronic modules and components (sensors, actuators,microprocessors,etc.) must be used to an advantage and open source software can glue all the parts together. I agree with you that exact specifications must be used as guides to implementation. I hope that everyone on this group had read your documents. Thanks you for going to the effort of producing them.?
--Ron N7TFZ
arrrgg
so many under spec solutions!!! I took to twitter to have a little rant on the topic.
I'm really hoping that we can get all these clever teams to start collaborating.
It seems to me that so many teams are starting with underspecified MVPs.
I'm still trying to figure out what can be done about achieving the goal of inter-team collaboration. I'm not sure my twitter rant will achieve much.
Erich Schulz,?mbbs, mba, fanzca 0410 277 408
On Wed, 8 Apr 2020 at 16:38, < quad@...> wrote: The China bag squeezer is quite ingenious with 3rd world local parts.?
A nice "bag squeezer" from Vanderbilt??
Nice DIY negative pressure Curiass ventilator effort -
|
Hi Baskan
Not sure if you've had a chance to review my documents - I'd be very happy to have a senior engineer review them and link to resources and comment etc.
I'll not respond re the exhalation valve (although the I personally think it's pretty simple and clever). I discuss alternatives in the docs.
I need to add a section on "the case against the bag squeezer" - I covered this a bit in my on twitter, and bit in the docs.
The key problem I see is that I don't believe BVMs as being robust enough (not just the bag but also the very delicate valves) to deal with the duty cycles in a sick COVID patient with damaged, stiff and vulnerable lungs. (I just picked up the one on the floor in my study, and yup opinion unchanged!). Robustness requires coping with 20 cycles a minute for weeks, and operating at 35cmH2O - remember that an ambu bag lives in someones hand which migrate around the bag over time spreading the stress. A mechanical squeezer won't fiddle and is going to stress the one point till it fails.
Also I see the nearly all bask squeezers as being hard to modify to be dynamic and to synchronise with the random actions of a patient.
I like the features of this group's design as I can see how it could be integrated into a fully specified ventilator.
I think the essential requirements missing from this design are: * able to deliver pulses of gas up to 120l/min (this design probably achieves this)
* ability to sense and respond rapidly (in a supportive manner) to patient respiratory effort (including coughing) * easy to use with a touch screen (ie plug in a laptop and get the kids to write some nice software)
With the right design I think a far more durable and powerful replacement can be assembled for the same cost as an ambu bag - the thing we would shed is lightness and portability - but they aren't necessary features in a Covid pandemic.
Hope that makes sense. Would value feedback! cheers Erich
Erich Schulz,?mbbs, mba, fanzca 0410 277 408
On Thu, 9 Apr 2020 at 06:44, Baskan Kalezade < bkalezade@...> wrote:
Hi there, Greetings to all heroes..?
I am a senior electrical engineer with some previous experience about car tyre nitrogen inflator systems and microcontrollers. I am new to your group and sorry if I might missed or misunderstood any e-mails..
Constructing David's? rubber exhalation valve seemed not handy for me. And an adjustable inspiratory pause is possible?only with? a controllable exhalation valve. (I 've already built a very simple 2 solenoid-valve ventilator with a compressor just?for POC purposes.? Since my? exhalation valve was 1/2 '? the airway pressure was high. I am almost about to order 1' valves although they are a little bit costy.)
And Now I am totally confused since I also noticed those increasing number of automated? AMBU (BVM bag) projects you mentioned. They seem to be a clean / complete solution with manual peep valves, over pressure protection, exhalation with a proven security.?
@Erich, @Dr.Flywheel, do you think that if we integrate pressure sensor ,O2 sensor to an automated BVM bag,? may that?correspond most of the specs of a real ventilator.
Listing UFHealth Ventilator Engineering Specs below, I am looking forward to?hear?your answers to analyse which one of specs below,? can not correspond in any circumtances?with an automated BVM bag.
Tidal Volume: Yes? (not precisely but maybe calibrated/tuned.) Respiratory Rate: Yes? I:E Ratio: Yes PEEP Valve: Yes (On the mask)
Anti-asphyxia valve: Yes? (on the mask)
Over-Pressure Valve:Yes? ?(on the mask)
Plateau pressure: (with ambu bag squeezing speed trajectory ?)
Peak pressure:(with ambu bag squeezing speed trajectory ?)
Inspiratory Pause: ? (may need a solenoid valve)
Spontaneus Breathing: ? (check valves)
In-built blender: ?
Oxygen Sensor: (Can be placed)
Thanks for your answers and for this great group.. Best Regards,
Baskan
Dr. Flywheel < Dr.Flywheel@...>, 8 Nis 2020 ?ar, 20:34 tarihinde ?unu yazd?: Erich, Sorry about your frustrations. This world has become too visually oriented and YouTube definitely contributed to this effect on people. While we see so many variations of mechanical AMBU (BVM) bag squeezers, most people do not understand that this type of "dumb" device is only appropriate for a short-term? ambulatory mitigation of breathing assistance. It may work well with lungs that are fully or at least mostly functional. However, due to lack of feedback from the patient's physiology and in the case of COVID-19 infection, an escalating series of defects in the lung functionality, a dumb device may kill the patient, instead of sustaining their lives. Most people are not aware that even with the most sophisticated ventilators, pulmonary knowledge-based supervision of the machine (at least setting its mode of operation) must be exercised to match the dynamics of the patient's lungs.
I believe that in his group we have people who can combine cross disciplinary knowledge to the point where we can bridge over the gaps of the functionality that must be augmented on-top of dumb air-supply devices. This augmentation must be using sensors and signal analysis to match the air delivery system to the dynamics of the patient's condition,?including CO2 exhalation levels. Modern, cheap and off the shelf electronic modules and components (sensors, actuators,microprocessors,etc.) must be used to an advantage and open source software can glue all the parts together. I agree with you that exact specifications must be used as guides to implementation. I hope that everyone on this group had read your documents. Thanks you for going to the effort of producing them.?
--Ron N7TFZ
arrrgg
so many under spec solutions!!! I took to twitter to have a little rant on the topic.
I'm really hoping that we can get all these clever teams to start collaborating.
It seems to me that so many teams are starting with underspecified MVPs.
I'm still trying to figure out what can be done about achieving the goal of inter-team collaboration. I'm not sure my twitter rant will achieve much.
Erich Schulz,?mbbs, mba, fanzca 0410 277 408
On Wed, 8 Apr 2020 at 16:38, < quad@...> wrote: The China bag squeezer is quite ingenious with 3rd world local parts.?
A nice "bag squeezer" from Vanderbilt??
Nice DIY negative pressure Curiass ventilator effort -
|
i would caution against any design that is based on wireless technology. More than once, one ofmy?residents has been logging ANOTHER PATIENT IN ANOTHER OPERATING ROOM. You have no idea how dumb doctors can be.? ?And then you got the nurses too!! Furthermore, you add a whole nother set of RISKS and elecgtromagnetic?sgtandards that have to be listed and studied.? ? I think that's a real mistake in my humble opinion.
What is really impressing me is the professionalism of our professional coders who are working right down to the itty bitty failure methods of sensors that have been used for years and years and are made in the hundreds of millions -- and they are STILL working on what to do if that sensor fails to respond.? ?That is extremely good engineering.? ?My hat is off to them!!!
Hi Baskan
Not sure if you've had a chance to review my documents - I'd be very happy to have a senior engineer review them and link to resources and comment etc.
I'll not respond re the exhalation valve (although the I personally think it's pretty simple and clever). I discuss alternatives in the docs.
I need to add a section on "the case against the bag squeezer" - I covered this a bit in my on twitter, and bit in the docs.
The key problem I see is that I don't believe BVMs as being robust enough (not just the bag but also the very delicate valves) to deal with the duty cycles in a sick COVID patient with damaged, stiff and vulnerable lungs. (I just picked up the one on the floor in my study, and yup opinion unchanged!). Robustness requires coping with 20 cycles a minute for weeks, and operating at 35cmH2O - remember that an ambu bag lives in someones hand which migrate around the bag over time spreading the stress. A mechanical squeezer won't fiddle and is going to stress the one point till it fails.
Also I see the nearly all bask squeezers as being hard to modify to be dynamic and to synchronise with the random actions of a patient.
I like the features of this group's design as I can see how it could be integrated into a fully specified ventilator.
I think the essential requirements missing from this design are: * able to deliver pulses of gas up to 120l/min (this design probably achieves this)
* ability to sense and respond rapidly (in a supportive manner) to patient respiratory effort (including coughing) * easy to use with a touch screen (ie plug in a laptop and get the kids to write some nice software)
With the right design I think a far more durable and powerful replacement can be assembled for the same cost as an ambu bag - the thing we would shed is lightness and portability - but they aren't necessary features in a Covid pandemic.
Hope that makes sense. Would value feedback! cheers Erich
Erich Schulz,?mbbs, mba, fanzca 0410 277 408
On Thu, 9 Apr 2020 at 06:44, Baskan Kalezade < bkalezade@...> wrote:
Hi there, Greetings to all heroes..?
I am a senior electrical engineer with some previous experience about car tyre nitrogen inflator systems and microcontrollers. I am new to your group and sorry if I might missed or misunderstood any e-mails..
Constructing David's? rubber exhalation valve seemed not handy for me. And an adjustable inspiratory pause is possible?only with? a controllable exhalation valve. (I 've already built a very simple 2 solenoid-valve ventilator with a compressor just?for POC purposes.? Since my? exhalation valve was 1/2 '? the airway pressure was high. I am almost about to order 1' valves although they are a little bit costy.)
And Now I am totally confused since I also noticed those increasing number of automated? AMBU (BVM bag) projects you mentioned. They seem to be a clean / complete solution with manual peep valves, over pressure protection, exhalation with a proven security.?
@Erich, @Dr.Flywheel, do you think that if we integrate pressure sensor ,O2 sensor to an automated BVM bag,? may that?correspond most of the specs of a real ventilator.
Listing UFHealth Ventilator Engineering Specs below, I am looking forward to?hear?your answers to analyse which one of specs below,? can not correspond in any circumtances?with an automated BVM bag.
Tidal Volume: Yes? (not precisely but maybe calibrated/tuned.) Respiratory Rate: Yes? I:E Ratio: Yes PEEP Valve: Yes (On the mask)
Anti-asphyxia valve: Yes? (on the mask)
Over-Pressure Valve:Yes? ?(on the mask)
Plateau pressure: (with ambu bag squeezing speed trajectory ?)
Peak pressure:(with ambu bag squeezing speed trajectory ?)
Inspiratory Pause: ? (may need a solenoid valve)
Spontaneus Breathing: ? (check valves)
In-built blender: ?
Oxygen Sensor: (Can be placed)
Thanks for your answers and for this great group.. Best Regards,
Baskan
Dr. Flywheel < Dr.Flywheel@...>, 8 Nis 2020 ?ar, 20:34 tarihinde ?unu yazd?: Erich, Sorry about your frustrations. This world has become too visually oriented and YouTube definitely contributed to this effect on people. While we see so many variations of mechanical AMBU (BVM) bag squeezers, most people do not understand that this type of "dumb" device is only appropriate for a short-term? ambulatory mitigation of breathing assistance. It may work well with lungs that are fully or at least mostly functional. However, due to lack of feedback from the patient's physiology and in the case of COVID-19 infection, an escalating series of defects in the lung functionality, a dumb device may kill the patient, instead of sustaining their lives. Most people are not aware that even with the most sophisticated ventilators, pulmonary knowledge-based supervision of the machine (at least setting its mode of operation) must be exercised to match the dynamics of the patient's lungs.
I believe that in his group we have people who can combine cross disciplinary knowledge to the point where we can bridge over the gaps of the functionality that must be augmented on-top of dumb air-supply devices. This augmentation must be using sensors and signal analysis to match the air delivery system to the dynamics of the patient's condition,?including CO2 exhalation levels. Modern, cheap and off the shelf electronic modules and components (sensors, actuators,microprocessors,etc.) must be used to an advantage and open source software can glue all the parts together. I agree with you that exact specifications must be used as guides to implementation. I hope that everyone on this group had read your documents. Thanks you for going to the effort of producing them.?
--Ron N7TFZ
arrrgg
so many under spec solutions!!! I took to twitter to have a little rant on the topic.
I'm really hoping that we can get all these clever teams to start collaborating.
It seems to me that so many teams are starting with underspecified MVPs.
I'm still trying to figure out what can be done about achieving the goal of inter-team collaboration. I'm not sure my twitter rant will achieve much.
Erich Schulz,?mbbs, mba, fanzca 0410 277 408
On Wed, 8 Apr 2020 at 16:38, < quad@...> wrote: The China bag squeezer is quite ingenious with 3rd world local parts.?
A nice "bag squeezer" from Vanderbilt??
Nice DIY negative pressure Curiass ventilator effort -
|
Pulmonary medicine is a specialty and requires many years of studying, internship and practical experience. The human body heart/lung system is very complex. I will leave it to the experts to guide us in how we can assist with better solutions, even if such emergency?solutions are less than ideal. I am not such an expert!.?
The following?note reflects my understanding of the problems that the medical emergency is encountering. The text is simplified to allow more people to understand the current situation:
From first hand testimony?(relative who works as ER Primary Dr.) I got report of cases where patients who were treated at the ICU with mechanical?ventilators, died while their blood oxygen levels were presumably "normal". At the same time hematology test indicated?that these patients had very high blood CO2 and nitrogen levels. This phenomenon remained unexplained for a while, until a recently (an emergency) published paper (not peer reviewed yet) provided a rather convincing analysis.
Apparently, the COVID-19 RNA is binding with the special molecules within normal human hemoglobin (Porphyrin) to lock the iron that sits at the center of that molecule, from being accessible to binding with air contained within the lungs. Note that hemoglobin in the lungs serves to both absorb oxygen from inhaled air, as well as remove CO2 from the bloodstream into exhaled air. If the Porphyrin molecule is locked by the virus, the effectiveness of both O2 absorption and CO2 exhaust is severely hampered unless the human body produces increasing quantities of new hemoglobin that the virus did not have the opportunity to affect.
While the above situation is rather complex, this is just one of the examples of how unsupervised mechanical ventilation may be counter productive, particularly since the action of the virus proteins are not fully understood. In addition, introducing pressurized air into the patient lungs, though helpful in enabling dissolved oxygen flow to reach lung tissue that is surrounded by blocking fluids (in infected patients), there is a great risk that?over-pressure will rupture the jeopardized thin tissue of the?Alveoli (lung air sacs) and cause complete collapse.
Any mechanism that is not allowing the patient's own lungs participate in the assisted ventilation?is therefore very dangerous. In the case of COVID-19 infection, it seems like besides exhaled air volume, pressure and PEEP, real-time monitoring of exhaled CO2 levels becomes extremely?important?too. Regardless, the patient condition may deteriorate while being mechanically ventilated, necessitating immediate medical personnel attention and possible recovery action. Accurate real-time monitoring of key physical indicators withing?the ventilation system seems to be key to life saving success.
For further information I suggest to look at these linked resources, as well as the attached paper:
--Ron N7FTZ
On Wed, Apr 8, 2020 at 1:44 PM Baskan Kalezade < bkalezade@...> wrote:
Hi there, Greetings to all heroes..?
I am a senior electrical engineer with some previous experience about car tyre nitrogen inflator systems and microcontrollers. I am new to your group and sorry if I might missed or misunderstood any e-mails..
Constructing David's? rubber exhalation valve seemed not handy for me. And an adjustable inspiratory pause is possible?only with? a controllable exhalation valve. (I 've already built a very simple 2 solenoid-valve ventilator with a compressor just?for POC purposes.? Since my? exhalation valve was 1/2 '? the airway pressure was high. I am almost about to order 1' valves although they are a little bit costy.)
And Now I am totally confused since I also noticed those increasing number of automated? AMBU (BVM bag) projects you mentioned. They seem to be a clean / complete solution with manual peep valves, over pressure protection, exhalation with a proven security.?
@Erich, @Dr.Flywheel, do you think that if we integrate pressure sensor ,O2 sensor to an automated BVM bag,? may that?correspond most of the specs of a real ventilator.
Listing UFHealth Ventilator Engineering Specs below, I am looking forward to?hear?your answers to analyse which one of specs below,? can not correspond in any circumtances?with an automated BVM bag.
Tidal Volume: Yes? (not precisely but maybe calibrated/tuned.) Respiratory Rate: Yes? I:E Ratio: Yes PEEP Valve: Yes (On the mask)
Anti-asphyxia valve: Yes? (on the mask)
Over-Pressure Valve:Yes? ?(on the mask)
Plateau pressure: (with ambu bag squeezing speed trajectory ?)
Peak pressure:(with ambu bag squeezing speed trajectory ?)
Inspiratory Pause: ? (may need a solenoid valve)
Spontaneus Breathing: ? (check valves)
In-built blender: ?
Oxygen Sensor: (Can be placed)
Thanks for your answers and for this great group.. Best Regards,
Baskan
Dr. Flywheel < Dr.Flywheel@...>, 8 Nis 2020 ?ar, 20:34 tarihinde ?unu yazd?: Erich, Sorry about your frustrations. This world has become too visually oriented and YouTube definitely contributed to this effect on people. While we see so many variations of mechanical AMBU (BVM) bag squeezers, most people do not understand that this type of "dumb" device is only appropriate for a short-term? ambulatory mitigation of breathing assistance. It may work well with lungs that are fully or at least mostly functional. However, due to lack of feedback from the patient's physiology and in the case of COVID-19 infection, an escalating series of defects in the lung functionality, a dumb device may kill the patient, instead of sustaining their lives. Most people are not aware that even with the most sophisticated ventilators, pulmonary knowledge-based supervision of the machine (at least setting its mode of operation) must be exercised to match the dynamics of the patient's lungs.
I believe that in his group we have people who can combine cross disciplinary knowledge to the point where we can bridge over the gaps of the functionality that must be augmented on-top of dumb air-supply devices. This augmentation must be using sensors and signal analysis to match the air delivery system to the dynamics of the patient's condition,?including CO2 exhalation levels. Modern, cheap and off the shelf electronic modules and components (sensors, actuators,microprocessors,etc.) must be used to an advantage and open source software can glue all the parts together. I agree with you that exact specifications must be used as guides to implementation. I hope that everyone on this group had read your documents. Thanks you for going to the effort of producing them.?
--Ron N7TFZ
arrrgg
so many under spec solutions!!! I took to twitter to have a little rant on the topic.
I'm really hoping that we can get all these clever teams to start collaborating.
It seems to me that so many teams are starting with underspecified MVPs.
I'm still trying to figure out what can be done about achieving the goal of inter-team collaboration. I'm not sure my twitter rant will achieve much.
Erich Schulz,?mbbs, mba, fanzca 0410 277 408
On Wed, 8 Apr 2020 at 16:38, < quad@...> wrote: The China bag squeezer is quite ingenious with 3rd world local parts.?
A nice "bag squeezer" from Vanderbilt??
Nice DIY negative pressure Curiass ventilator effort -
|
Ron
What you are bringing up are the findings that now more and more are coming out of the field.? It is probably not a pneumonia? type of infection? that leads to the ARDS in the first place.? Many findings now points towards the? blocking of transport of Oxygen and CO2? into and out of the red blood cells is the start of the very rapid transition into ARDS.? ?Perhaps, as you point out, we need to pay attention to this in our design.?
Rolf K9DZT?
|
This paper is interesting but hopefully I can contextualise it for you.
Most of this is outside the control of the ventilator. If a surge ventilator gets the basics right and meets standard ARDS ventilator specifications then as the clinical protocols evolve (I am seeing daily changes based on rapidly increasing experiences), then the ventilator will cope.
Ie, things a ventilator can and should be able to control: - pressure wave form (resp rate, TV, PEEP, IE ratio, slope)
- synchronisation with patients' own respiratory efforts (as detected by pressure/flow sensors)
- information on pressures and volumes available to the clinicians (ideally integrated, although potentially a sensor housing could connect to an external monitor)
Then ventilator should also (this isn't hard) be able to interface with mechanisms that control - temperature and humidity of gas (via a standard OSA CPAP humidifier)
- FiO2 (hopefully incorporated into the ventilator, or adjustable by an external blender)
- gas analysis (confirming actual FiO2, and capnography) - this is traditionally a separate monitor connected via a fine hose at the patient end
All the rest of it is stuff the ventilator cannot control.
Hope that makes sense in terms of defining the boundary between the engineering challenge and the clinical one. e
Erich Schulz,?mbbs, mba, fanzca 0410 277 408
On Thu, 9 Apr 2020 at 09:48, Rolf Ekstrand < rekstrand@...> wrote: Ron
What you are bringing up are the findings that now more and more are coming out of the field.? It is probably not a pneumonia? type of infection? that leads to the ARDS in the first place.? Many findings now points towards the? blocking of transport of Oxygen and CO2? into and out of the red blood cells is the start of the very rapid transition into ARDS.? ?Perhaps, as you point out, we need to pay attention to this in our design.?
Rolf K9DZT?
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I think I solve all the Problems for a Cheap Ventilator,
The EPV100 will save you a lot of time and money?
This paper is interesting but hopefully I can contextualise it for you.
Most of this is outside the control of the ventilator. If a surge ventilator gets the basics right and meets standard ARDS ventilator specifications then as the clinical protocols evolve (I am seeing daily changes based on rapidly increasing experiences), then the ventilator will cope.
Ie, things a ventilator can and should be able to control: - pressure wave form (resp rate, TV, PEEP, IE ratio, slope)
- synchronisation with patients' own respiratory efforts (as detected by pressure/flow sensors)
- information on pressures and volumes available to the clinicians (ideally integrated, although potentially a sensor housing could connect to an external monitor)
Then ventilator should also (this isn't hard) be able to interface with mechanisms that control - temperature and humidity of gas (via a standard OSA CPAP humidifier)
- FiO2 (hopefully incorporated into the ventilator, or adjustable by an external blender)
- gas analysis (confirming actual FiO2, and capnography) - this is traditionally a separate monitor connected via a fine hose at the patient end
All the rest of it is stuff the ventilator cannot control.
Hope that makes sense in terms of defining the boundary between the engineering challenge and the clinical one. e
Erich Schulz,?mbbs, mba, fanzca 0410 277 408
On Thu, 9 Apr 2020 at 09:48, Rolf Ekstrand < rekstrand@...> wrote: Ron
What you are bringing up are the findings that now more and more are coming out of the field.? It is probably not a pneumonia? type of infection? that leads to the ARDS in the first place.? Many findings now points towards the? blocking of transport of Oxygen and CO2? into and out of the red blood cells is the start of the very rapid transition into ARDS.? ?Perhaps, as you point out, we need to pay attention to this in our design.?
Rolf K9DZT?
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Marcelo Varanda