The Idea
There is a global shortage of Personal Protective Equipment (PPE) for healthcare providers (HCP) due to the rising COVID-19 pandemic. Many hospitals are already facing shortages of surgical masks, face shields and N95 respirators with some healthcare providers being asked to re-wear their gear that is meant to be single use.
We also recognize the increased need for Non-Invasive Positive Pressure Ventilation (NIPPV) during this pandemic to improve patient outcomes by avoiding intubation where possible since only 20% of patients intubated survive. NIPPV comprises an air-tight mask connected to a continuous positive airway pressure (CPAP) or a bilevel positive airway pressure (BiPAP) machine, and it can be used to treat COVID-19 patients.
Our team is exploring, testing and validating the use of snorkel masks for these two cases:
Non-Invasive Positive Pressure Ventilation (NIPPV, such as CPAP or BiPAP)
An alternative form of PPE for healthcare providers
Project Snorkel Mask is based on the Isinnova Charlotte Valve, a valve designed in Italy in early March 2020 to adapt a snorkel mask for use with a CPAP machine. This device was originally designed to address a shortage of certified CPAP ventilator masks in an emergency situation, in use for places where there was not sufficient supply of approved masks.
NIPPV Patient Snorkel Mask
Our NIPPV project addresses a current need for masks for COVID-19 patients in respiratory failure who:
Have failed treatment with low flow supplemental oxygen (SpO2 <92% on max flow),
Require non-invasive positive pressure ventilation (NIPPV), and
Do not meet the criteria for intubation and mechanical ventilation
This is a stop gap measure to help prevent patient lungs from collapsing for those on the brink of intensive care where no respirators are available and to avoid having to intubate. Our masks can be used for patients in hospitals needing a CPAP/BiPAP-style intervention.
This can be used in cases where the patient is not quite sick enough to warrant ICU intervention (such as organ failure and respiratory distress) and intubation, but is still showing signs of respiratory distress and inadequacy (decreased oxygen saturations and increased oxygen requirements). CPAP therapy can also be deployed in places without access to invasive ventilation, and can be an alternative to early intubation, which is thought to improve outcomes. However, CPAP also poses a significant infection risk using conventional CPAP masks due to the aerosolization and leakage of infectious viral particles thought to be able to linger in the air for several hours. This would mean putting staff and nearby patients at greater harm. Thus, a tight seal is crucial for safely providing this potentially life-saving treatment by adapting the snorkel mask for this use with mask fitting already built in. Our goal on this project is to mitigate the spread of aerosolized viral particles associated with NIPPV to improve outcomes.
PPE Provider Snorkel Mask
Our second project is exploring the snorkel mask as a form of PPE for health-care providers in the face of shortages of N95 respirators and face shields. The snorkel mask would be fitted with a 3D printed adapter that would allow a HEPA filter to be attached to filter particulates. This project is aimed at doctors, nurses, hospital staff and care home workers who do not have access to FDA- approved medical PPE, with the goal of protecting the user from the surrounding environment.
The Design
How it Works
A typical snorkel mask has two or three channels, each with one or more one-way valves. This allows air to enter the mask during inhalation through one channel expiration to escape to escape through the other(s). The openings to these channels are usually found on the top of the mask.
Our team has adapted two open-source CAD models which connect to the openings at the top of the snorkel mask. We are adapting these models for three snorkel mask models currently available on the market in the BC Lower Mainland. We are designing and prototyping our adaptors using 3D printing.
For the non-invasive ventilation mask, our adaptor allows the intake channel on the snorkel mask to be connected to a CPAP or BiPAP machine, and the other channel(s) connected to a PEEP filter. This allows for the patient to breath in a similar way to if they were wearing a certified CPAP mask.
For the PPE mask, our adaptor ensures air both entering the snorkel mask is passed through a HEPA filter.
What stage is our design at?
Our designs are currently being tested for qualitative and quantitative fit and compliance with ISO standards, as well as developing disinfection and sterilization procedures for re-use of snorkel masks.
The following tests are being conducted and running for both projects:
Qualitative Fit
Quantitative Fit
CO2 Accumulation
Patient Rebreathing
Patient Rebreathing and Resistance Under Single Fault Conditions
Usability Testing
Advantages
The snorkel mask design for patients and providers is cheap to produce and scale up with easily accessible materials and is simple to use. Mask fitting are already built-in and the use-case has already been validated and currently in use in Europe. The mask is also potentially reusable for repeated use after proper decontamination. This can help mitigate some of the supply chain challenges that we are seeing globally in order to protect providers and increase a patient’s chances at recovery by avoiding intubation where possible.
Disadvantages
No long term research and data has been produced yet and it is not a permanent solution since this was not the original intended use of the mask. Minor disadvantage is getting consistency and standardization across different 3D printers which can be overcome through mass production with a manufacturer.
Design Specifications
Our team has modified a DasMeer full face snorkel mask by adding a 3D printed, custom fit adapter to the top outlet that will allow the mask to be connected to a high efficiency particulate air (HEPA) filter. Filters meeting the HEPA standard must satisfy certain levels of efficiency. Common standards require that a HEPA air filter must remove—from the air that passes through—at least 99.95% (European Standard) or 99.97% (ASME, U.S. DOE) of particles whose diameter is equal to 0.3 μm; with the filtration efficiency increasing for particle diameters both less than and greater than 0.3 μm.
Inhaled air will enter through the top outlet via the filter and the adapter. Exhaled air will travel through the exhalation check valve at the mouth/chin. The internal tubing along the side of the mask will also allow for exhaled air to circulate back up the mask and be released via the top outlet through the filter.
Full face snorkel mask
We have purchased two different snorkel masks, DasMeer and Aqualung.
3D-printed Adapter
We have reversed engineered a 3D printed adapter for both the Dasmeer and the Aqualung snorkel mask. The adapter is printed using PLA filament. The base of the adapter connects to the snorkel mask outlet and the top part of the adapter connects to an ISO standard 22mm viral filter.
Filters
We are using readily-available commercially-produced HEPA filters, both of which are pictured above. They are currently used ubiquitously in respiratory therapy, intensive care units and anesthesia/operating room, and both can connect to ISO standard 22mm tubing and connectors. As of April 15th, 2020, we are not aware of any product shortages in the supply chain.
FAQ
+ Who are you?
We are a group of Engineers, Physicians, Students and other professionals based out of Vancouver Canada.
+ Is the Snorkel Mask Health Canada Certified?
We are working with Canadian manufacturers with ISO 13485 certification and we are currently applying for Health Canada approval. During the current Covid-19 situation, Health Canada has issued an Interim Order (IO), which will help expedite the process.
+ Is the mask reusable?
Yes. The mask and adapter are reusable and we recommend our cleaning and decontaminating by washing it with soap and water or with a solution of water with 10% bleach. If using bleach, rinse the mask and straps well to avoid bleach residue.
+ Is it tested at the same level of an N95 mask?
Qualitative and quantitative testing shows that it passed at the level of an N95 mask or higher. Please see contact us for the latest test results.
In January 2021, Kate Koh from the Snorkel Mask team shared her experience and reflection with COSMIC to UBC Medical Journal Blog.
Congratulations, Kate, for making it this far with COSMIC and Team Snorkel Mask!
You can read more about the article here!
The Snorkel Mask Team
Lead: Kate Koh
Members: Ryan Yan, Louise Chen, Colleen Ogilvie, Ivan Gourlay, Sarah Bornais, Wan Yi Koh, Jade Varelle, Kenny Le, Justin Chan, Kiran Rikhraj