This is not a regular press release nor this is an article to point out discrepancies in the global efforts being done for achieving a low-cost ventilator design for mass-production.
Rather this is an article to share our findings so far on the matter and point everyone in the right direction so that maximum energy and time can be spent on the right things instead of reinventing the wheel.
The whole world is talking about COVID-19. It has turned our world upside down in just a matter of weeks, and the human race is scrambling to adapt to this new pandemic.
COVID-19 is spreading through the world population at unbelievable speed.
Pakistan had its first 1000 cases in 30 days, second 1000 cases in 7 days, third 1000 cases in 5 days, fourth 1000 cases in 3 days, fifth 1000 cases in 4 days!
Let’s hope we begin flattening the curve soon!
Reduced ability to breath
For the majority of COVID-19 positive people, the symptoms are mild. For the others, the virus activates the immune reaction of the body to disproportionate levels resulting in a whole spectrum of lower respiratory tract symptoms. The mildest presentation might be primary or secondary pneumonia, while the extreme form might be fibrosis of lungs giving rise to a rapidly life-threatening situation where the lungs cannot perform their basic function that is inflation and deflation to pump air in and out to make the transfer of oxygen and carbon dioxide in and out of the blood. This necessitates not just hospitalization but shifting to mechanical support of respiration with the help of ventilators.
As of TODAY, we do not have a cure for COVID-19. Most of the patients get well on their own. Most of those hospitalized with moderate symptoms have to be supported by the available symptomatic treatment that includes antivirals, steroids, antihistamines, antibiotics, and many other medicines. Plasma transfusion from recovered donors at this stage might be of help as well. However, the real problem is to save the lives of extremely sick patients who need mechanical ventilation.
The shortage of ventilators
All over the world – hospitals are experiencing a huge load of COVID19 patients. And we don’t have enough ventilators to cope with the crisis.
This has led to an international movement of calling all capable of manufacturing ventilators to join the fight against this common enemy.
Pakistan has nearly 3844 ventilators out of which as many as 1000 ventilators are defective. The National Disaster Management Authority (NDMA) has put in an initial requirement of 10,000 ventilators for meeting the emergency. A country of our size should at least have 150,000 to 200,000 ventilators ideally.
Time is quickly running out… our intensive care units for COVID-19 response are empty right now in Pakistan but soon would be overloaded in the coming weeks.
To best of our knowledge, the ambitious undertaking by Pakistan Airforce (PAF) for producing ventilators at PAC (Pakistan Aeronautical Complex) Kamra has the capability of producing 1000 units per month; efforts are underway to scale-up the production.
This design is by Dr. Mujeeb U Rehman and a non-exclusive manufacturing agreement has been signed with PAC, Kamra.
Another undertaking by Project Management Organization (PMO), Pakistan Ordinance Factory (POF) and NESCOM (National Engineering and Scientific Commission) are also underway.
The PakVent1 by NESCOM is under clinical trials at CMH.
We hope that it sails through the DRAP (Drug Regulatory Authority of Pakistan) approval process quickly and the mass-production is started to meet the demand.
These initiatives would take time to scale-up to meet the need.
This, however, won’t come even close to fulfilling the demand that is yet to peak. There is this impending doom looming over us that soon hospitals in countries even like the US will experience what Italy has already experienced — An overwhelming flood of patients.
The crowd-sourcing and the open-source movement
Hundreds and Thousands of enthusiastic engineers who want to help out are volunteering around the globe with their expertise to develop a low-cost ventilator that any manufacturing facility could adapt to build.
Every single design; we have come across till now, centers around one key bit of technology: A BVM, or bag valve mask, more commonly referred to as an Ambu Bag.
BVM are plastic bags that a clinical care practitioner can manually deflate with their hands. It’s what a first responder would use if a patient wasn’t breathing, instead of giving mouth to mouth resuscitation.
It’s a cheap and easy way to force air into the lungs. All these designs are just robotic arms that can squeeze this bag at a set frequency endlessly.
They, of course, can be manufactured quickly and in great numbers.
Ventilators are not just air pumps!
Ventilators aren’t just air pumps that force air into a patient’s lungs.
One of the primary problems facing doctors currently is managing a side effect of mechanical ventilation, barotrauma (baro = pressure; trauma = wound).
Without proper management of pressure, volume, air temperature, and humidity; mechanical ventilation can cause great harm to the lungs and may even cause death.
This is very serious business!
How do the lungs operate?
We first need to understand how the lungs function under normal circumstances.
Two muscle groups typically act to control breathing. The diaphragm, which is a large muscle that separates the abdomen from the chest, and the intercostal muscles which are the muscles that reside between the bones of your rib cage.
When you breathe in your diaphragm contracts, which causes it to move toward the abdominal cavity, while the external intercostal muscles between the ribs also contract which lifts the rib cage outwards. Both of these actions
increase the volume of the thoracic cavity, the cavity that your lungs reside in.
The increase in volume causes a corresponding decrease in pressure, which allows air outside the body at atmospheric pressure to fill the lungs and equalize the pressure.
The key thing to note here is that negative pressure drives inhalation. The lungs don’t inflate like a balloon. They expand and equalize with atmospheric pressure. On an exhalation, the process reverses with a small spike above atmospheric pressure to push the air out again.
Simple but bad ventilator designs
Mechanical ventilation cannot work like this by just pumping air.
It has to force air into the lungs from the outside and essentially blow the lungs up like a balloon. If this is not tightly controlled the air pressure could work against the diaphragm and the intercostal muscles and end up increasing the pressure in the alveoli above their typical max pressure.
The alveoli are tiny thin air sacs in the lung that are in contact with blood vessels to allow oxygen and carbon dioxide to diffuse between the blood and the lungs. To do this they have to be extremely thin and because of that, they are very delicate pieces of tissue.
Over expanding them will lead to inflammation at best or rupture at worst. This is what barotrauma is.
To make this worse, those suffering from acute respiratory distress syndrome, like those affected by COVID-19, are more at risk of suffering from this side effect of mechanical ventilation, as the alveoli that are filled with fluid prevent air from entering them, causing the pressure to elevate even higher in the functioning alveoli. The last thing we want to do is damage the healthy tissue of a patient suffering from damaged lung tissue.
That is the opposite of helping.
To avoid this! Doctors need to carefully choose their settings on a ventilator.
The primary guidance for this is to limit the volume and pressure of air entering the lungs.
So, any low-cost ventilator will need a method to control these settings.
Designs like this one, which can only vary it’s volume output, as far as we can tell, by connecting the pushrod closer to the center of rotation of the cam. There is no variable control here. This device would likely do more harm than good.
Irresponsible PR campaigns
Several massive multi-million dollar companies, who present these designs as their own have done zero research into what is needed from a ventilator and just built something as quickly as possible to get some positive PR for their company.
How did BVM based designs begin?
As far as we can tell, the earliest design that proposed using these BVM was from an MIT student project in 2010. This paper has been online for quite a while and if people are truly copying it, they are leaving out some clever design ideas that make it more functional.
Their design included a spirometer, which measures the air flow rate out of the BVM, by integrating this value they can calculate the volume of air delivered.
This then feeds into a controller which can vary how tightly the BVM was squeezed to change the volume of air delivered. This gave the device a nice range of tidal volumes ranging from 200 milliliters to 750.
This is a better design and may be useful in a do or die situation. But, it is not perfect.
In the MIT design, the breaths per minute controller are simply set on a time-based frequency, ranging from 5 to 30 breaths per minute.
This is called a mandatory breath. It’s entirely determined by the machine. You will take a breath whether you like it or not. This would be uncomfortable and requires the patient to be heavily sedated to the point of paralysis, but it can also exacerbate barotrauma if the patient’s diaphragm and intercostal muscles are resisting the inhalation.
High-performance ventilators can provide mandatory breathing, however, they also provide assisted ventilation.
Their breath sequences are normally triggered by the patient. They are still able to breathe. They just need help because they are exhausting themselves with the effort. To do this, the machine needs some way of triggering the breath cycle and ending it too, based on observations of the patient. This can be done in several ways.
It can be pressure triggered, where a sensor detects a drop in airway pressure indicating the thoracic cavity is expanding. It can be flow triggered, where a sensor detects airflow into the lungs, or it can be triggered by a sensor detecting electrical activity of the diaphragm, indicating that the diaphragm
is contracting to expand the thoracic cavity.
This also requires very fast microprocessors to detect and react to the triggers. We have seen no low-cost ventilators incorporating this vital component of ventilator design so far. And it truly is a vital component.
A very difficult part of the ventilation process is weaning people off it. A ventilator that requires someone to be sedated to the point of paralysis makes it very difficult to get them breathing naturally on their own
Some of the weaning techniques include: SIMV synchronized intermittent mandatory ventilation; PSV pressure support ventilation; VS volume support; VAPS(PA) volume assured pressure support (pressure augmentation); MMV mandatory minute ventilation; APRV airway pressure release ventilation.
There is a multitude of other design considerations to be made with ventilators.
Ventilator Induced Lung Injury (VILI) and Prevention
As you’ve already read, COVID-19 patients frequently develop an acute respiratory distress-like syndrome, or ARDS, which not only fills the alveoli with fluid, making gas exchange harder but also increases the likelihood of the alveoli collapsing shut at the end of every breath out.
This is because diseased areas of the lung don’t produce surfactant normally. Pulmonary surfactant is a clever substance produced by alveolar cells that coats their inner surface and one of its key jobs are keeping these tiny sacs open when the lungs are deflated, which is what happens in healthy lungs.
But in ARDS, when you breathe out, those alveoli collapse shut and sometimes whole sections of the lung collapse, called atelectasis. Trying to force them open with every breath requires more pressure and hugely increases the risk of barotrauma.
We use positive end-expiratory pressure or PEEP, to try to prevent the barotrauma.
Positive-End-Expiratory Pressure (PEEP)
Imagine you’ve got your head out of the window of a fast-moving car with your mouth open, don’t do this, by the way, you have a constant air pressure exerted on your airway, making it ever so slightly harder to breathe out. That’s PEEP.
PEEP is a constant positive pressure that prevents those alveoli collapsing at the end of each breath and also helps open up — or recruit — collapsed areas of the lung.
In COVID-19 we are seeing patients requiring very high levels and tight control of PEEP to maintain their oxygen levels and protect the lungs and this is something that a basic bag-squeezing vent cannot achieve.
From the mechanisms we have seen so far, we are very much concerned about the possibility of baro and/or volu-trauma.
When the rubber meets the road!
Most of these patients are on a ventilator for a few weeks at the moment. A basic bag-squeezer might be adequate for the first day or so when a patient is deeply sedated, but simply won’t work as you try to ease off the sedatives.
Additionally, your upper airways warm and humidify air entering the lungs, but they are taken out of the equation by the endotracheal tube which goes directly into the lower airways. Without the warming and humidifying features of modern ventilators, lung tissue will get rapidly damaged.
It’s not the gun… but the man behind the gun!
And while we do need more ventilators, what’s even more valuable are the intensive care nurses and respiratory therapists to work them, but they take significantly longer to produce.
REPEAT: Ventilators are not just air pumps
So, as you can probably tell by now, there is a lot more to ventilation than just pumping air into a patient.
Tight regulation of Pressure, volume, oxygen percentage control, and humidification would all require more complicated mechanics than these simply BVM pumps.
DRAP Requirements and Approval
Federal Minister for Science and Technology, Chaudhry Fawad Hussain said Pakistan Engineering Council (PEC) has approved two designs of the ventilators out of 48 received to date.
In a tweet, the federal minister said the selected two designs of the ventilators have been sent to the Drug Regulatory Authority of Pakistan (DRAP) for final approval.
This shows that designing a ventilator fit for proper use is no joke.
Just take a look at the specifications put forward by NDMA for the ventilators as well as the acceptance testing procedure for fast track approval of ventilators by PEC. The requirements and acceptance criteria are well defined and require pretty much advance measurement and control systems.
BlueEast’s path journey so far
We have been closely studying the major open-source and closed-source ventilator design initiatives for the last several weeks.
We originally embarked on three tracks:
- Designing our ventilator
- Following MIT E-Vent design for possible collaboration and mass-production at our parent company’ factory
- Licencing the ventilator design for mass-production at our parent company’s factory
Designing our ventilator
We made digital prototypes and experimented with Ambu-bags and made a few of our designs.
Here are sketches of some of our early designs:
Our prototype consisted of a stepper motor pushing sheet metal clamps up and down to squeeze the Ambu-bag. The design is simple, no need for position encoders. The motor has to have high durability to sustain the duty cycles. The breath rate and the force with which the Ambu-bag could be squeezed was adjustable through a micro-controller.
This design needed access to sheet-metal fabrication facilities and raw material. Since this design was made in the first week of lock-down, we were highly skeptical about the degree of success in making the physical prototype in the highly constrained situation. As a design back-up, we also started on a 3D printer friendly design. Ironically, 3D printers are hard to come by because of restrictions on imports by the government. The government should give a second thought on why is it restricting the imports of the 3D printers?
The second design consisted of a design minimum parts and that too could be 3D printed.
It just needed guide-rods and custom design of the Ambu-bag to fit into a compact design. Again the stepper motor mounted at the base was needed to compress the Ambu-bag.
No need for position encoders just make sure no steps are missed by the motor by using clever firmware and electronics.
The breath rate and the force with which the Ambu-bag could be squeezed was adjustable through a micro-controller.
As we made progress and researched more on the ventilators and the minimum requirements needed for successful mechanical ventilation by the ICUs and respiratory therapists – it became clear that ventilator design is a serious business and the simple designs being worked-on were going to do more harm than benefit.
It would take more time and energy to design our ventilator that fulfills the requirements of an emergency ventilator. For now, we have stopped all efforts in this regard. But in the process learned very valuable insights into ventilator designing.
We started keeping a watch on several global collaborations for an open-source and/or crowd-sourced design for a low-cost ventilator.
Soon we found that most promising efforts were from MIT on an Emergency Ventilator Design Toolbox.
This is a very promising design. However, work is still going on to refining the design and fulfilling the minimum requirements. We are keeping a close watch and gathering all the new information that is arising. Especially the work on Assisted Breathing is still underway and being finalized and tested.
However, it is clear that to mass-produce it at Orient, there would be a significant engineering effort required to make the production transition based on the parts and materials that can be made available in this part of the world.
Licensing existing designs
Our engineering team also remained on the look-out for manufacturers who would be licensing their designs or existing products.
We found two very high potentials.
We are in talks with Dr. Mujeeb U Rehman.
He has principally agreed to collaborate with us but cited that his team is heavily engaged with PAC, Kamra and would only be able to collaborate once the team gets free with their previous engagement.
We agreed to stay in touch with him.
Meanwhile, we have downloaded all the design specifications given by Medtronic PLC. The data is huge and is being organized for a proper production transition and sourcing activity. The plan is to start mass-manufacturing at Orient for the ventilators.
We are aware that ventilators are a matter of life and death and are thus are fully focused on the durability and the reliability of the design. Once the design is complete, we plan to take the design to PEC (Pakistan Engineering Council) and DRAP (Drug Regulatory Authority of Pakistan) that operate on strict guidelines and standards.
Many designs presented to them beforehand have been rejected because they lacked the proper documentation for certification. Only 3 designs out of 48 submitted with PEC have been approved so far and forwarded to DRAP for clinical trials and final approval.
We will keep our improvements open-source and help other serious people in setting up the mass-production of our improved ventilators. We would be making periodic public updates about our progress as we proceed.
We also want to be upfront on the fact that BlueEast, as well as our parent company Orient Group of Companies would be donating our services as well the ventilators mass-produced in this time of need to the public and private hospitals in Pakistan.
Abdul Rehman Talat (CEO BlueEast and Director Orient Electronics) commented that “We are not ventilator experts; we are chipping in our financial and engineering resources to help the nation in this time of need. We would discontinue our pro-bono work and mass-production of the ventilators when we as a nation get out of this situation and WHO degrades COVID-19 from its current pandemic status.”
We are in it together!
Designing a ventilator fit for purpose with cheap and easy to manufacture components is a difficult job, but we are positive a viable product will come to light soon.
Especially as this is not a new problem. Poorer countries have been struggling with the lack of cheaper medical supplies for years has helped fuel innovation and passion for young engineers.
We are all in this together, and we again hope this article doesn’t come across as a teardown of well-intentioned engineers trying to help.
It’s much easier to point out the flaws in design than to put in the time to design something yourself. This is just an attempt to point people in the right direction.
Inspiring future generations of engineers and living innovation is the mission of BlueEast and our parent company, Orient Group of Companies.
Calling in all the help we can get!
If you have an idea or a skill that you want to pitch-in to fight COVID-19, we would love to have you on-board.
Please write to us at email@example.com
We are in this together!
As we make progress, updates will be shared about the lessons learned so far and the achievements made….