Video introduction to the design here

This repository contains all the design files necessary to assemble a gravity ventilator. Please read license.pdf before using any of the files to understand the liabilities and limitations you are responsible for by using this repository.

NOTE: At this point, this is not a medical device, meaning that the device is NOT medically approved for human use, and as such, improper use can result in harm or death of anyone using the ventilator. It is still in its development stages and any use in a clinical setting should be under the strict consultation and supervision of qualified healthcare experts and/or qualified biomedical engineers.

In February 2020 amidst the CoVid-19 pandemic, concerns about a global shortage of ventilators began to surface and these discussions rapidly became a reality. We sought out to find a local solution to the rapidly evolving crisis, working alongside the hundreds of open-source projects worldwide, aimed at tackling the same problem.

We believe that we add a novel solution to a landscape dominated by automated bag-valve mask compression devices. Built using readily-available materials and utilizing resources routinely found at a patient’s bedside, our aims were to produce a device capable of being produced at a sub-$100 price point for low-resource settings, as well as a more robust model, both founded using the same principles.

Modern commercial ventilators are complex machines with specialized components. According to the Department of Health and Social Care guidance statement on Rapidly Manufactured Ventilator System Specification (20/03/2020), ventilators must meet certain criteria to be considered “clinically acceptable”.

RMVS-compatible ventilators must be capable of providing one of two modes of ventilation. The first is mandatory ventilation, wherein the patient is completely sedated, and all work of breathing must be done by the ventilator, according to preset criteria (e.g. tidal volume, respiratory rate, E/I ratio). Supportive ventilation, on the other hand, is used when the patient can do some work on their own. The machine must be able to sense when the patient is attempting to inhale (and provide inspiratory support), and when the patient is exhaling (and provide expiratory support).

The basis of the gVent system is gravity, water, and two cylindrical vessels fitted together to create a pressurized system. This pressure can then be used to ventilate a sick patient. The two vessels are each sealed at one end. The larger vessel is filled with water; the smaller vessel is placed inside the larger vessel.

Air is then introduced into the system from the hospital's O₂ outlet. A clinician can thus control the FiO₂ by titrating the amount of hospital air to the amount of delivered O₂. As this pressurized gas builds up in the system, the top cylinder is displaced upwards from its resting position, commensurate to the weight of the top cylinder (which can have weight added to adjust the pressure).

To deliver air, a valve is opened, releasing the pressurized air/O₂ mixture through to the intubated patient. And with the valve controlled on an electronic circuit, the operator has the ability to control important respiratory parameters, including respiratory rate, I:E ratio, and the volume of air delivered to the patient.

1. The Assembly Instructions document for the gVent can be found at The COSMIC Medical Website.
2. In order to view the code and upload it to the Arduino, download and install the Arduino IDE.

See the CONTRIBUTOR.md file in the root of the repository for guidelines and additional instructions.

As per our understanding, hardware is not covered by copyright. However, we present our work under the TAPR OHL license insofar as it applies. All software and documentation is licensed under Apache 2.0.