A Novel Respiratory Mask Designed with Vacuum Suction to Eliminate Infected Aerosols
This was my senior project at UCSD, working in a group of four with Dr. Jeremy Orr, a Pulmonary and Critical Care Physician at UC San Diego Health.
Leaks are a common problem with respiratory masks used for non-invasive ventilation in hospitals. This problem is both a loss of oxygen delivered to the patient, and an increased risk of infected aerosols spreading from beneath the mask seal. Around the onset of Covid-19, Dr. Orr came up with an idea for a vacuum assisted mask that would in theory evacuate any infected droplets that escaped from beneath the initial skin / mask barrier, and also improve oxygen deliverance to the patient.
Over 15 weeks, our team‹s job was to take Dr. Orr‹s initial low-fidelity prototype and redesign a fully functioning proof of concept from the ground up in order for Dr. Orr to adequately showcase his idea to potential stakeholders.
My Role
Due to the nature of this product and industry, this project revolved a lot around ergonomics, materials, and organic modeling. My team worked together on every aspect of the project, but we each took specialties within the design, and mine was the design and modeling of the silicone vacuum channel.
There were a lot of key factors to consider for the design and performance of this channel, but here are a few:
- Variability in facial features and size
- Balancing stiffness of silicone material
- Feasibility of prototyping a pourable mold
- Comfort on face
- Modeling a unique contoured channel
- Creating a realistic test bed
- Operating pressure range
- Impact of facial and patient movement
One of the main difficulties with this project was the impact that very small contours could have on each prototype. A vacuum seal only works if the seal can adequately compress against the opposing material surface, conforming to fill all gaps where air could escape through. Thus, it is easier to achieve this with a more flexible material, like a low shore hardness silicon. However, a too flexible material used for this mask would completely collapse the channel structure. A higher shore hardness material would solve this issue, but then the channel is less likely to conform to the patients face unless under a higher vacuum source pressure which proves a problem for comfortability and duration of wearing.
A second main difficulty was testing our prototypes effectively and efficiently. The only way to truly evaluate each design to the complexity of the scenario was to physically mold each silicon channel design and resin print each new mask design. This led us to spend a lot of time also optimizing and testing molds using 3D FDM printing on home and workshop printers.
We also spent a lot of time getting our pour just right...
And I spent lots of time getting just the right curvature profile...
This shows the change between two prototypes that finally caused the vacuum seal to hold (Orange to Green).
Ultimately, we were able to make a final proof of concept prototype that was effective testing in a lab with an actual hospital wall vacuum source and test subject - me.
See the full project website and Dr. Orr‹s mask website below!