Omedica Ventilator

grabcad

The Omedica Ventilator delivers positive pressure ventilation using a controlled continuous spinning fan blower to deliver air and optionally supplemental oxygen to the patient. Mainly, it consists of two systems: pneumatic (with off-the-shelf pressure, flow rate, and temperature sensors) and a simple PCB-Control system based on a Raspberry Pi computer with a touch LCD screen. An ATX-Computer power supply is used with input voltage and frequency ranges of 90 to 250 V AC and 50 to 60 Hz, respectively. If AC power is unavailable, the ventilator may be connected through an DC input connector to an external DC power source (5 to 12 V DC), such as an automobile power port, or optionally in future versions powered directly from the internal battery (14 V, nominal). The touch LCD screen is used to enter breath delivery parameters. Breath delivery parameters are based on a closed-loop control system that adjusts the speed of the fan blower. The speed is controlled to the patient pressure signal or the inspired flow signal depending on whether pressure ventilation or volume ventilation is selected. The fan blower speed varies according to the ventilation mode, ventilator settings, and whether the ventilator is in an inspiratory or expiratory phase. The speed of the blower adjusts under software control using a Raspberry Pi/Arduino controller. Using measurements from pressure and flow sensors on the Sensors board, the inspiration phase can be defined and controlled according to the setting mode selected above. In this design, after discussing the Hardware design concept of ventilators, the theory of operation and functionality is mainly based on literature and a free source of a commercial ventilator by Medtronic (Puritan Bennett 560). Some parts are downloaded from GrabCAD to shorten development time and minimize risk affecting patients in such critical pandemic situations. Many thanks to Medtronic for making this valuable source available and free. The Medtronic model above was analyzed to determine if our designs meet requirements in practical details and compatibility with medical principles and regulations. The status of the project as of May 1, 2020, is ongoing: 90% design source files (e.g., computer-aided design CAD) needed to iterate on the design mechanically; 80% production files (e.g., STL files used by 3-D printers to make mechanical components); 60% printed circuit board (PCB) layouts and other electronics design files to allow production and design evolution of the electronics; 70% bill of materials (BOM), which is needed to evaluate components employed and find alternatives; 80% list of tools required, which are needed to determine if a device can be fabricated in an open-source community; 70% wiring diagrams used to assemble the device with electronics; 60% firmware and software (porting part of codes and new GUI), which are needed to run the actual device; and 30% instructions for assembly, so makers can fabricate the device when parts are made or acquired. Next, existing resources will be used to accelerate proof of design over the next three weeks. Lastly, as this is a rapidly evolving situation, future work will focus on enabling widespread mass-distributed manufacturing of open-source ventilators to fight against the current COVID-19 pandemic and provide devices to low-resource regions worldwide.