Noah Ziemba
Foam Bag Valve Mask
This was a senior design project through the University of Pittsburgh focused on redesigning the bag valve mask (BVM). When patients are unable to breathe, it is very important that they receive oxygen back to their lungs as soon as possible. The first step in this process involves the use of a BVM. A BVM is composed of a mask that seals around a patient’s face and a bag that is used to pump air into the patient. Often, one person must use this device alone. This can lead to difficulties in properly sealing the mask on the patient preventing proper ventilation. Our team's goal was to improve the ability for single individuals to properly seal BVMs.
Unmet Clinical Need Identification
I traveled to various emergency medical stations in Pittsburgh to learn about struggles faced by emergency medicine providers. Through this initial outreach, we learned that BVM fitting issues are a very common clinical need. Further visits with these personnel showed us that there are no real solutions for improving BVM performance beyond user experience and practice. Because of this, we decided to pursue a solution to this issue.
Initial outreach performed at various EMS stations in the Pittsburgh area.
Development
We began the iterative design process with sketches of potential solutions created by each team member and compiled them into four potential design directions:
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a pressure distribution tool to more easily hold the mask
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a foam mask attachment
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a foot pump for the ventilation bag that allows two hands to hold the mask
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ear hook straps to fix the mask to the patient's face.
Sketches of various initial design ideas.
I brought the sketches to EMS stations, Pitt EMS center, and other locations and discussed them with EMTs, paramedics, and EMS instructors. Discussions conveyed to us additional needs and requirements of BVMs, where easy removal of masks and preference to no additional steps or training allowed us to quickly kill off the ear hook, foot pump, and pressure distributor designs. With the foam mask concept remaining, our team constructed several prototypes:
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a standard BVM with a one-layer medium density foam insert
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a standard BVM filled with gel beads
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a wide raw foam BVM
Initial prototypes of masks. From left to right, top to bottom: foam insert, gel beads, raw foam.
We presented them to medical professionals once again for feedback and informal testing on CPR mankinis which showed that the gel bead and wide foam masks required less pressure to create a sufficient seal on the face, potentially reducing hand fatigue.
I developed risk documentation around these prototypes such as an initial hazard analysis (IHA), risk summary, fault tree analysis (FTA), and failure modes and effect analysis (FMEA). Creation of these documents helped guide our team to pursue a foam-based mask due to risks present in the gel-bead based mask.
Testing performed on prototypes at Wiser Simulation lab at University of Pittsburgh.
To conform to irregular facial geometry, a medium-resolution prototype with multiple layers of foam of varying densities was produced via a laser cutter. Further feedback and informal testing from medical professionals will guide our design to a design freeze in January and subsequent V&V testing in the spring semester.
Current prototype of mask utilizing multiple layers of different density foams to conform around face.
Verification and Validation
I assisted in the development of a product design specification for the BVM device. Based on these specifications, I developed a preliminary verification test plan that will be followed in the projects next semester. The device's functional requirements that will be tested are:
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Device functionality over lifecycle
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Device provides tight seal and fit
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Device requires little training for providers
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Device attachment point on bag valve
We will test for material properties and ensure the prototype can withstand certain environmental specifications. Factors identified through the risk management process will be tested by ensuring a seal is formed with multiple angles of use.
Delivery of user needs will be assessed through validation testing with established emergency medicine contacts.
Future Direction
The Bag Valve Mask improvement was created based on data from unmet clinical needs with the goal of improving fit with risk minimized and the work documented in a DHF following the FDA’s Quality Systems Regulations specifically design controls in 21 CFR 820.30. The next steps involve finalizing the design, freezing the design, and performing extensive Verification and Validation Testing to ensure the device meets product specifications and user needs.