COVID CPAP

Conversion of full face snorkel masks to CPAP.

PAGE LAST UPDATED 08/04/20 - file with adaptor for Das Meer/Leucothea type masks.

Links posted on Thingiverse .

As the world faces the Covid19 pandemic, innovative ways are being found to support Covid19 patients in respiratory distress. The concept of using Full Face Snorkel Masks came originally from the doctors at the Gardone Valtrompia hospital helped by engineers from Isinnova. They released the design of the adaptor so that it could be used by anyone, however it did not connect well to British hospital systems.

In March 2020, the first cases of Covid19 were confirmed in the Isle of Man. Discover Diving working with engineers from Ronaldsway Engineering, Cortech, Jantys and Strix have developed this project and refined the adaptor design. Working with the critical care team at Noble's Hospital, Isle of Man we have shown that the system will allow the delivery of high pressure oxygen and filter the exhaled air from the patient. We have printed versions in PLA and SLA.

Version A (STL file available now)
This adaptor will only connect onto Decathlon Subea or Tribord branded masks. They can be recognised by the Subea logo printed at the top. This is a modified version of the original Italian design. The clip for holding the adaptor to the mask has been strengthened. The inlet and outlet accept standard 22mm taper fittings as used by the NHS in the UK. A large letter A is embossed on the design for type identification.

Version B (STL file available now)
This adaptor can be used with snorkel masks of the following brands
Leucothea/Das Meer/Mosfiata/Baracuda/Siliber/Fondo Sub/Sea180/HelloYee
This adaptor also accepts the standard 22mm taper fittings. A large letter B is embossed on the design to help identify the adaptor type.

NB These adaptors cannot be used with other brands of snorkel mask. The adaptor will not fit masks with hinged snorkel attachments.
ALL MASKS MUST BE MODIFIED BEFORE USE. REMOVE THE CHIN DRAIN VALVE COVER. CAREFULLY REMOVE THE MUSHROOM VALVE. REPLACE THE MUSHROOM VALVE INVERTED.

DISCLAIMER: THIS EQUIPMENT HAS NOT BEEN TESTED AND CERTIFIED FOR MEDICAL USE. PATIENTS AND MEDICS MUST BE AWARE OF THE RISKS. NO LIABILITY IS ACCEPTED. THIS INFORMATION IS SHARED IN GOOD FAITH AT A TIME OF HEALTH CRISIS.

This system was tested with the critical care team at Noble's Hospital. We used standard fittings and oxygen hose, but could get higher flow rates using drain tube with a wider bore. Flow should be adjusted so that you can see the filter lift slightly as the wearer exhales. The wearer will find it easy to breathe in with the positive pressure, but will feel a slight exhale resistance. We monitored in the oronasal space for CO2 retention and rebreathing and found it to be minimal.

The masks are comfortable to wear. The internal silicon face seal makes a good seal as long as you don't trap hair in it. The elastomeric straps sat comfortably against the head. Be careful not to over tighten and crush the seal.

The fit of the masks is important. See the guide posted above for details on sizing. Fit masks on by placing the chin onto the silicon seal first. It's important to get the oronasal compartment sat properly to prevent gas recirculation. Decathlon Subea/Tribord masks have the sizing printed in small letters on the exhale hose.

CARE AND MAINTENANCE
Please check that the chin valve has been inverted (the mushroom top is on the inside of the mask). This will seal as the patient exhales, but if the gas supply fails then will allow the patient to inhale ambient air.

Please check that both mushroom valves either side of the oronasal seal are in place and lying flat. Do not remove these valves, they prevent CO2 build up inside the mask by ensuring directional gas flow.

Masks can be cleaned by immersion in 1 in 10 dilution of Chemgene for 20 minutes. Rinse 3 times in fresh clean water (discarding after each wash). Dry the masks inverted. Do not autoclave.