OXY-ALL Emergency Ventilator

OXY-ALL Emergency Ventilator by Tanmay Benjwal, Indranil Kundu, Kunal Pandey, Dhruv Chakravarty Nath is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.

Based on a work at https://www.instructables.com/OXY-ALL-Emergency-Ventilator/.

1. Micro-controller ( Arduino )
2. Servo Shield
3. 16x2 LCD display
4. LCD breakout board
5. MG995 Servo Motors x 2
6. Jumper Wires
7. 9V 1A adaptor (for power supply)
8. 5V 2.1A battery pack (power back-up)
9. Acrylic Sheet
10. 3D printed rack and pinion arrangement

The world here is going through a tough phase of this pandemic situation of COVID – 19 and it is very difficult for the people to restart their jobs and at the same time be equally safe from this. The pandemic situation has led to several new inventions that are widely in use to protect the spread of this deadly virus from the infected person to the other. Italy was the first European country to be hit by the epidemic. Since the first case of infection was reported in the Lodi/Codogno area on February 21st, the situation in Italy has evolved rapidly, with the largest number of confirmed cases and deaths in the Northern regions, where the pressure on the health system has been very strong. Following Asia, India was one of the countries which was hit by Covid variants at a deadly rate. Many people lost their lives and still are fighting from this pandemic.

As we saw what India went through the second wave in the months of May and June in 2021. The Indian medical system was collapsed, the situation was out of control. The most havoc was created because of the scarcity of oxygen. Acknowledging the main factor, we created this ventilator for the convenience for the people who are in the need of oxygen, who are unable to get oxygen cylinder from the hospitals. This ventilator is cost economic and portable which enhances it awareness for the needful people.

1- Is it possible to safely ventilate a COVID-19 patient by automatically actuating a manual resuscitator?

Our process in approaching this question is to first identify the minimum requirements for a low-cost ventilator, based on the collective wisdom of many clinicians; design against these requirements; conduct immediate testing; report the results; iterate and facilitate discussion. Manual ventilation is a short-term solution in a critical care environment, without any apparent clinical evidence regarding the safety of long-term use (days-weeks). There are multiple scenarios in which respiratory support could be needed: patients can be awake or asleep, sedated or sedated and paralysed, breathing spontaneously, weaning off of a vent, etc. Furthermore, changing clinical presentations with ARDS require shifting minute ventilation (tidal volume ✕ respiratory rate) to “lung-protective” strategies, which place patients at risk for things like auto-PEEP. Some of these situations are simpler than others, with the simplest being ventilating a sedated, paralysed patient. In such a situation, at a minimum a safe emergency ventilator could be used to free-up a conventional ventilator. Any solution should be utilized only in a healthcare setting with direct monitoring by a clinical professional. While it cannot replace an FDA-approved ICU ventilator, in terms of functionality, flexibility, and clinical efficacy, the OXY-LIFE is anticipated to have utility in helping free up existing supply or in life-or-death situations when there is no other option. Further, any low-cost ventilator system must take great care regarding providing clinicians with the ability to closely control and monitor tidal volume, inspiratory pressure, bpm, and I/E ratio.

2- We update and summarize the role of spontaneous breathing during mechanical ventilation in ARDS, which can be beneficial or deleterious, depending on the strength of spontaneous activity and severity of lung injury. Future studies are needed to determine ventilator strategies that minimize injury but maintaining some diaphragm activity.

Mentioned Below are some of the research papers we went through. You can download and have a look at same.

NOTE: THE BELOW DOCUMENTS ARE JUST FOR REFERENCE AND ALL THE CREDITS GOES TO THEIR RESPECTIVE OWNER/OWERS.

Citations:
https://emergency-vent.mit.edu/ https://journals.lww.com/co-criticalcare/Abstract...

The OXY-ALL Ventilator is a simple device that pumps oxygen when the patient is unable to breathe naturally. Artificial Manual Breathing Unit (AMBU) bags are used to pump oxygen directly to the nose and mouth of the patient. The AMBU has to be pressed either manually by the medical professional or can be pressed using an automation mechanism. Two servo motors (MG995) are used to press the AMBU bag which on pumping provides air at the outlet end. The servo motors are actuated to run a rack and pinion type gear arrangement which converts rotary motion to linear motion.

The ventilator uses 3 main parameters to decide the functioning of the system as per the requirement of the patient. These parameters can vary various patients. The 3 parameters are: Respiratory Ratio(RR), Inhale Exhale Ratio (IE) and Volume of Air( Vol). These parameters can be set using potentiometers on the ventilator system. Vol decides the volume of air to be pumped to the patient and the extent to which the patient can breathe manually. Some patients may require a lower volume as they can partially breathe in naturally through their nose, while others may require a large volume as they are unable to breathe at all naturally. RR is another parameter which is the number of breathing cycles (1 breathing cycle = 1 inhale + 1 exhale) of the patient in 60 seconds. IE is the Inhale to Exhale ratio and it tells us the ratio of time of Inspiration to the time of Expiration. Using the above parameters we have written a code which can artificially provide oxygen to the patient, potentially saving their life. Respiratory Rate (RR) (breaths per minute): between 6 – 40. Note that the low RRs of 6 – 9 are only applicable to Assist Control. Tidal Volume (TV) (air volume pushed into lung): between 200 – 800 mL based on patient weight. I/E Ratio (inspiratory/expiratory time ratio): recommended to start around 1:2; best if adjustable between range of 1:1 – 1:4*. *Range determined based on several COVID-19 patients’ ventilator settings reported from Boston area ICUs. The 3 different potentiometers that are used in the circuit are used to control the various parameters respectively as: Pot 1 – Varies inspired volume, sets angular oscillation of the arms. During operation, each arm varies by a maximum of approximately 20°, corresponding to fully squeezing a large bag. This dial varies position from 0% (fully open) to 100% (fully compressed). Pot 2 – Varies the BPM. This sets the rate from 0 to the maximum BPM given in the clinical document. Pot 3 – Varies the I:E ratio. Range as given in the clinical document. The Ventilator having dimensions of 36*20*17 cm (L*B*H) has been fabricated using an acrylic sheet which is firm and graceful. It is lightweight, compact in size and has a handle at the top of the ventilator to carry easily. The design comprises a Resuscitator ( 1 AMBU bag, an oxygen pipe, mask) , 2 servo motors, 3 potentiometers to vary the parameters like Volume, RR (Respiratory rate) and I/E (Inspiratory : Expiratory). At the rear end of the box, two hinge joints have been installed so that whenever a person wants to change the AMBU bag, it can be easily replaced just by opening the top cover. An LCD display has been installed to show the different parameters and an alarm system is there to confirm the values which will be input by the medical professional. For any unforeseen situation an emergency button has been installed to suddenly stop the machine.

Here, below is the 1st prototype of the ventilator that was designed:

Set-up:

The main aim of this project was to develop a cost-effective ventilator system. This was achieved by making the system as compact as possible to potentially cut-down costs. 3D printing technology was used to make the system efficient and cost-effective. The ventilator system is compact and easily portable so that it can be used by almost anyone at any place as per the requirement of the patient. The frame is made of Acrylic Sheet (polymethyl methacrylate), which provides a sturdy and strong structure as a frame to the system. The two servo motors are actuated using the microcontroller which then pumps the AMBU bag to provide oxygen to the patient directly. The AMBU bag is replaceable and hence the top cover can be opened to do so. The cover has a lock so that no one else can tamper with the system inside other than the respective authorities.

Linear Actuator was the most important aspect/part of this device. So we wanted to be sure that everything is gonna work. We finalized the rack and pinion design for our ventilator, we considered this is because Tinkercad has a very good gear making pre set assembly.

Here we used Progear from shape generator in Tinkercad for designing purpose of the same. Follow the guide and screenshots added to make one although the .stl files are added below you can download them and feel free to edit them for your puprose or any design improvement is appreciated.

The design of the ventilator system was developed on tinker CAD. Some parts of this model were 3D printed. The rack and pinion gear arrangement and servo motor holder slot was 3D printed. The design of this was taken the tinker CAD model and converted into .stl file and these files uploaded on Cura Slicer. The application which then generates a G-code which is taken by the 3D printer, the final product was then obtained around ~ 4 hours of 3D printing.

Slicer setting:

print speed - 80 mm/s

Layer height - 0.2mm

Filament- PLA

Hot End temp - 180 deg C

Bed temp - 60 deg C

Code developed was to actuate the servo motors using the micro-controller. The code for micro-controller was done keeping in mind the medical parameters. The three parameters RR, IE and Volume were taking into consideration while developing the code for the ventilator system. The volume parameter decides the extent to which the AMBU bag would be pressed using the linear actuators. The IE and RR parameter would decide the delay of the interval between extension and retraction of the linear actuator.

The circuit is not so complex but the process is rather tiring because you have to place servo shield on Arduino Uno board/microcontroller and then you will have to solder the wires on the servo shield board.

1) The first process of assembly has been proceed with the design. So the decided to go with the acrylic sheet for the frame so that it would firm and durable.

2) Then we decided to make the 3d- printed rack and pinion so that the rack will push the AMBU bag towards inside.

3) we have used servo motor(MG 995) for high torque to actuate the pinion in a certain way.

4) On the front and back side we have made a hole to adjust the AMBU bag so that the oxygen pipe can be connected through the outside.

5) we have installed an LCD to display the parameters ( Vol , RR and IE).

6) we have installed 3 potentiometers to control 3 parameters ( VOL, RR and IE) and we have installed a switch button to turn on and off the ventilator. An emergency button also has been installed to stop the ventilator at that moment to tackle any unforeseen situation.

7) At the end, we have applied a rubber grip to cover the edges of the whole and frame.

The OXY-ALL Ventilator system was developed and a few problems were found in the 1st prototype that we developed. The main problem was power supply and power back-up in the ventilator system in the case of power failure. The ventilator system works on 5V power supply and hence we couldn’t use a higher voltage to protect the electronic devices in the system. This caused the LCD screen to flicker every time the servo motor was actuated. To solve this problem, we provided a dual power input to the system through the micro-controller. We provided 5V 2.1A using a battery /laptop power supply input and 5V 1A supply using power adaptor. This provided a stable power supply to the system and the LCD screen stopped flickering.

Another problem was cutting the acrylic sheet accurately. Slight deviation in the cutting process would result in a crack in the sheet and would damage the stability of the structure. We then used acrylic sheet cutter which would then precisely cut the sheet and not damage the structure as well. The code developed had several problems initially as we couldn’t integrate Respiratory Ratio (RR) and Inhale to Exhale ratio (IE) parameters simultaneously. This was a challenge as the two parameters are inter-dependent on each other and changing one meant that the other one would also be affected. This was later solved by using each parameter and changing them differently as per requirement on patient basis.

The OXY-ALL Ventilator was manufactured for only 4500 rupees (~$62). It is working fine and we are still working on improving design and efficiency of the ventilator. We will keep updating this Instructable. Although the Ventilator is made on published researched paper parameters and other open-source ventilators design we still are trying to improve it. We want that at no time there should be a situation where we need to use this ventilator, it is made and put up on Instructables for just in case situation and educational purposes for Human Welfare.