PLEASE NOTE: This webpage will NO LONGER be updated.   There is no support for these files and plans. 

PLEASE NOTE:  If you choose to build this or something similar, please consult with physicians, technicians and/or clinicians. 

PLEASE NOTE: We are getting some AMAZING feedback. Some Frequently Asked Questions are now posted below. 
Thank you so much for all of your interest.  It takes a village! 

DIY Instructions and Files

Skills

Assembly of the ApolloBVM should be possible with an intermediate to advanced machine assembly skill level. Operation of the device can be completed with intermediate expertise using the proper documentation, instructions, and files. Repair and maintenance of the ApolloBVM would be possible using this same documentation. Advanced knowledge would be required to access motion control and code framework to make gross modifications to the core functionality of the device.

Parts BOM

• Motors (2x) - goBILDA 2000 Series Dual Mode Servo (2000-0025-0002)
  Servo City    goBilda
• Arduino (2x) - Arduino Uno (A000066)
  Amazon    AdaFruit
• Wires - 22 AWG
  
• Power Supply - 7.5V (Model #vBK-UA-36)
  Amazon   
• Linear Gear (2x) - 20 Degree Pressure Angle Gear Rack, 32 Pitch (2662N53)
  McMaster   
• Gear (2x) - 32P, H23T Output Spline Servo Mount Gears (Metal) 32 Tooth (sku#615310)
  Servo City   
• Linear Bearing Rail with slider (2x) - MGN12 - 120mm (or longer but cut to 120mm)
  Aliaba    Robot Digg
• 1/4” Shaft (2x) - Dowel Pin, 1/4"x1" Long (98381A542)
  McMaster   
• 1/4” Shaft (2x) - Dowel Pin, 1/4"x1-1/2" Long (98381A546)
  McMaster   
• Spring (2x) - (P12-C029M16SQ64)
  McMaster   
• Gear Tension Screw (2x) #10-24 x 1.5"
  McMaster   
• Fasteners (36x) and washers (8x)
  
• Panel Mount 2.1mm DC barrel jack
  Mouser    AdaFruit
• Digital Screen - Serial 20x4 Liquid Crystal Display Module
  Mouser   
• Metal Buttons (1x) - Push Button with 360 Degree Rotary Encoder (Part#WYTP23) (KY-040 Rotary Encoder)
  Amazon    Bangood
• Push Button (1x) (3-109-081)
  Mouser   
• Emergency Stop Button (84-5020.0020)
  Mouser   
• Rocker Switch (RA11131121)
  Mouser   
• PLA Filament
  Prusament   
• 1/4 Birch Ply Sheet or plastic   
• BVM with PEEP - AMBU Spur II
  Ambu   
• ET endotracheal tube
     

Fasteners and Washers

*Note: Changed screw size from M2 to M3

**Note: Changed screw size from #10-14 x 3/4 to #10-1"

Download Mechanical Files

Motor Mount Assembly

Motor Assembly

You will need to make 2 of these for the finished design. 

Bumper Assembly

You will need to make 2 of these for the finished design. 

BVM Adjustable Mount

Software and Controls

The ApolloBVM system uses two coordinated microcontrollers in order to facilitate user input while guaranteeing uninterrupted airflow. The system has a master controller, responsible for managing the display and user input, and a slave controller that actually sends motor commands to the servos. This allows the master controller to operate entirely separately from the slave and ensures that the system is real-time safe. In order to give more clarity about the technical operation of this device, we will outline the operation of each controller separately.

In order to facilitate the various functions of the device, the slave controller operates in 3 distinct states: load, on, and off. While in the ‘load’ state, the slave controller will read ventilation parameters from the master over the I2C bus, generate a new trajectory with these parameters, and turn its state to ‘on’. While in the ‘on’ state, the device will follow the trajectory over and over for infinity. This means that the slave controller will never stop moving the motors unless it receives a command from the master to change its state to ‘stop’. If the master controller were to do so, the device would finish its current cycle and stop moving.

The master controller is mainly tasked with running the user display and sending commands to the slave. Internally, the master switches which panel is currently displaying and manages input from the encoder and buttons. Each panel that the master displays is programmed to follow a different behavior and is modular. This makes it easy to implement panels that behave completely differently and interact with the slave controller on the fly.

For implementation details, please refer to the Github repository where we documented source code.

Link to Github         Firmware Releases

User Interface

Key Specifications

Set up of Ventilation Parameters

All ventilation parameters must be set by the clinical provider caring for the patient. It is suggested to have the patient sedated with neuromuscular blockade for the acute phase of respiratory support. This may be followed by titrated sedation to a RASS score of -2. All patients should be continuously monitored during mechanical ventilation to include pulse oxygenation and also ideally continuous capnometry (end-tidal carbon dioxide -- ETCO2).

The minimum controllable parameters in order to ventilate a patient on ApolloBVM include:

PEEP Valve or Gauge

Most BVMs include a PEEP valve with an adjustable dial set for 20-40 cmH20. The purpose of this valve is to limit peak airway pressure to the number set on the dial. Ideally, peak airway pressure should be less than 40 cmH20. It will not be possible to measure PEEP with this valve.

Select BVM models include a PEEP valve with a gauge that ranges from 0-60 cmH20. These models allow for calibrated monitoring of PEEP during all portions of the breath cycle.

VT should be adjusted until the desired PEEP value is reached at the end of the breath cycle (8 cm H20 is a reasonable initial target).

With regard to ventilated COVID patients, it is quite likely that the desired PEEP will reach the 10-15 cmH20 range quickly.

Plateau Pressure

On an inspiratory hold of 0.5 seconds (at the end of the inspiratory portion of breath cycle), measured pressure should be <30 cmH20 to minimize ventilator-induced lung injury (VILI).

Emergency stop

There is an emergency shut-off button that turns off the device and allows for manual override and standard use of the BVM. (Version 1)

Supplemental Oxygenation

Most BVMs have a port to blend-in oxygen. Room air is 21% oxygen. Wall or tank-based oxygen is 100% oxygen. The higher the flow rate for ported-in oxygen, the higher the fractional percent of oxygen delivered to the patient. In acute ventilatory support, room air is often sufficient. Appropriate VT and PEEP are the keys to gas exchange.

Viral Filtration

HEPA filters should be placed on the ETT connector and then the filter is connected to the breathing circuit and BVM unit. This allows for all expired air at the point of exit from the mouth to be filtered prior to entering the BVM which contains an open aerosolization port.

Breathing Circuit

The use of a single-line disposable breathing circuit aids in the maintenance of heated and humidified air returning to the patient and also allows for placement of the ApolloBVM at a safe distance from the patient.

Testing Results

Version 1 Phase 1 Testing

Click HERE to see the Phase 1 testing results.

Updates

As updates are developed, they will be posted here.