India has an estimated 40,000 working ventilators, a number experts said will be inadequate in case there is a surge in Covid-19 infections that, in approximately 5% of the cases, sends patients to intensive care units (ICU) with acute breathing problems.The coronavirus attacks people's lungs, in some cases compromising their ability to breathe as they develop pneumonia. Ventilators, which deliver air to the lungs through a tube placed in the windpipe, are crucial to keep these patients alive. Mechanical ventilators are creating more problems than it is solving for ARDS patients.

What are the primary risks of a BVM/Mechanical ventilator?

Being viewed as a viable alternative to available professional care or delaying seeking professional care. This should be viewed as an educational resource or a last resort option only unless it’s medical viability is proven otherwise. Community driven engineering efforts like this run the risk of making it "too easy to be harmful" which would be a bad outcome. Using non-invasive interfaces (such as masks and mouth pieces) can create aerosolized viruses infecting the medical personnel working in close proximity to the patient. This can lead to exponential transmission of the virus. Usage should be restricted to places where aerosolized viruses are already abundant (lots of unmasked symptomatic individuals), COVID wards, or in isolation.

SOLUTION

In the event that COVID-19 hospitalizations exhaust the availability of FDA/ICMR approved ventilators. This project documents the process of converting the available compressed air and oxygen tanks at hospitals into a rudimentary non-invasive pressure support ventilator that could help with breathing during respiratory distress. It's an evolving project, but in its current form, it most aligned with the definition of a non-invasive pressure support BiPAP ventilator.

Bubble Helmets are used for patients suffering from Acute Respiratory Distress Syndrome (ARDS) which is also caused by COVID-19, the disease caused by the 2019 novel coronavirus. The helmet surrounds the patient’s entire head to supply oxygen and is sealed with a soft, airtight collar that wraps around the neck.

TECH STACK

Ventilator

Air gas inlet
O2 gas inlet
Air reflux valve
O2 reflux valve
O2 metering valve
Air metering valve
Mixing Tank
Mixed gas metering valve
Safety valve
Expiratory flow sensor
Barometric Pressure sensor
Calibration valve for inspiratory
pressure sensor
Inspiratory pressure sensor
Calibration valve for expiratory
pressure sensor
Expiratory pressure sensor
O2 sensor
Air pressure regulator
O2 pressure regulator
CO2 sensor
Neonatal flow Sensor
Nebulizer Mixer Valve
Nebulizer changeover valve
Nebulizer Outlet

Bubble Helmet

Bubble Helmet components can be made efficiently with 3D printing and industrial grade tools.

Medical Grade Plastic Material (Anyone can be used depending on the supply) :

Sustanat PC MG (Polycarbonate)

FibreTuff PAPC: The 3D printing material will be used to make Class A, Class B and Class C medical devices.

Medical grade Non-Latex Synthetic
RubberNeopreneBuna-N

PROTOTYPING

Initial design

Wireframe Desgin

Pneumatic schematic of the Ventilator.

1. Gas-mixture and gas-metering assembly. Gas from the supply lines enters the ventilator via the gasinlet connections for oxygen and air . Two nonreturn valves prevent one gas from returning to the supply line of the other gas. Mixing takes place in the tank and is controlled by two valves. Inspiratory flow is controlled by a third valve.

2. Respiratory unit consists of safety valve and two nonreturn valves . In normal operation, the safety valve is closed so that inspiratory flow is supplied to the patient’s lungs. During standby, the safety valve is open and enables spontaneous inspiration by the emergency breathing valve. The emergency expiratory valve provides a second channel for expiration when the expiratory valve is blocked.

3. Expiratory unit consists of the expiratory valve and a nonreturn valve. The expiratory valve is a proportional valve and is used to adjust the pressure in the patient circuit. In conjunction with the spring-loaded valve of the emergency air outlet, the nonreturn valve prevents pendulum breathing during spontaneous breathing.

4. Expiratory flow sensor.

5. Barometric pressure sensor. Conversion of mass flow to volume, body temperature and pressure saturated (BTPS) requires knowledge of ambient pressure.

6. Pressure measurement assembly. Pressure in the patient circuit is measured with two independent pressure sensors .

7. Calibration assembly. The pressure sensors are regularly zero calibrated by connection to ambient pressure via the two calibration valves.

8. Oxygen sensor.

9. Medication nebulizer assembly

HARDWARE
CAPABILITIES

Ventilator

This design can have a programmable breathing rate (ex: 10-30 cycles/min.)

It can have a programmed Positive End-Expiratory Pressure (PEEP).

The Ventilator is physically able to hit a peak air pressure of up to 45 cm of H2O.

PIP (Positive Inspiratory Pressure) : This gives the range of pressure we can have in the hyperbaric chamber (Bubble). (Range: 12 to 30 cm of H20)

Medication nebulizer assembly-It is easy and pleasant to breathe the medicine into your lungs this way. It is lacking in many other ways, but it is possible that this limited functionality could be helpful when better care is not available. It is also a starting point for making progress. Critical features can be added over time.

Bubble Helmet

The primary function of the Bubble Helmet is to provide the patient with oxygen rich air (as per the patient's requirement) and also at a higher atmospheric pressure (If required).

The Helmet is provided with Entry and Exit valves to facilitate the flow of air inside the Bubble Helmet.

Also two emergency holes are given in the plastic bubble acting as emergency valves to supply air to the patient using an ambu bag.

The patient does not feel claustrophobic, which is a common drawback of face mask based ventilators.