Patient Specific Oxygen Masks

Medical Study  
Imperial College London, 2016

Sleep apnea is a common condition that causes windpipe closure during sleep. Treatment involves supplying air via an oxygen mask, using generalised masks – causing a poor fit for most. The resulting leakage and discomfort reduces therapy effectiveness.

Specific silicon masks can be made via an injection mould and CNC machinery. Such methods aren’t economical however, and so are only used within academia. The aim of the study was to develop a workflow for the rapid manufacture of patient-specific oxygen masks, and to validate their performance.

To test this, 3 different head scans were selected from a database, for validation across a range of facial structures. Masks shaped to fit each were then made using Fusion 360.

By making a patient-specific mask, the compliance of a silicon mask wasn’t required to reduce leakage. Instead, the validated masks were redesigned to be entirely 3D printed – significantly improving the price-to-performance ratio. A laser-cut foam lining was integrated for patient comfort. 

After experimenting with underwater and foam techniques, I developed an acoustic method to measure leakage: a microphone was run across the mask-face interface, with the response used as a measure of leakage. This showed leakage magnitude and location –  more informative than conventional methods which just provide the total leakage flow rate.

The results confirmed the improved leakage performance, and were showcased at the Imperial College Additive Manufacturing conference. Additionally, it formed the basis of an ongoing PhD programme that’s developing the concept further. 

Riyadh Rateme 2018 — London, UK