Presentation on Day 2 of the Tissue Viability Society Conference, Newcastle 2018 https://tvs.org.uk/2018-conference/

1. Design considerations to
prevent pressure ulcers:
optimizing the respiratory mask interface
Zhichao Ma, Dr Javier Munguia
School of Engineering, Newcastle University
Javier.Munguia@ncl.ac.uk

2. Externally applied devices via Digital Design &
Manufacturing
Many recent concepts
enabled by low cost 3D
Printing…

3. Obstructive Sleep Apnoea (OSA) Syndrome
3
OSA
Low sleep
quality
Memory
loss
Stroke
Daytime
sleepiness
Traffic
accidents
Anxiety

4. It is estimated that the prevalence of
OSA in the overall population is 1−6%
The male to
female ratio for
OSA is in the
range of 2:1 or
3:1
Quintana-Gallego et. Al (2004)
SNORERS!

7. Typical masks [Fisher & Paykel Healthcare Ltd]

8. Ma,Drinnan, Hyde & Munguia (2018) Mask-interface for Continuous positive airway pressure (CPAP). Selection and
design considerations.

9. Mask types Side effects
Oronasal (Full-
faced) masks
Local skin damage (mainly red marks and pressure
sores) around the mask (particularly at the nasal
bridge and lateral side of nose)
Nasal masks Dry nose/mouth/ throat, local skin damage around
the mask (mainly on the lateral side of nose)
Nasal pillows Pressure sore inside the nose, nasal dryness, nose
bleeding, nose congestion and headache
Oral masks Dry mouth, dental pain, local skin damage around
the mask
Total face masks Local skin damage around the mask
Typical interface related facial side effects

10. Mask Interface Related Side Effects
10
Facial pressure ulcers
Allergy with mask Bleeding

11. Are there any design
recommendations or guidelines?

12. MASK DESIGN REQUIREMENTS AND
CONSIDERATIONS
Mask/interface
aspect
ARTP requirement
Materials *Mask/interface must be as soft and pliable as possible for max patient comfort.
*Materials independently certified as being medical grade, hypoallergenic substances
Size(s) * must be available in a range of sizes
Adjustment All masks must be fully adjustable including considerations for adjustable for height,
reach and rake
Disassembly,
Cleansing and
Reassembly
Must be capable of being disassembled and conversely capable of being correctly re-
assembled by the same user for the purposes of cleansing all component parts.
Re-use/Single
Patient Use
Required by legislation to be marked as either reusable or single patient use
Reusable masks must be able to withstand disinfection/autoclaving to recognized
hospital standards
Connection of
CPAP Machines
It must be possible to connect a CPAP machine from any manufacturer/vendor to any
CPAP mask/interface without adaptors
Lock/Release
Mechanisms
All full face masks should have a quick-release mechanism and must comply with
safety standards that avoid risk of asphyxiation in failure or a power-cut
Assembly at Point
of Sale
Masks/Interfaces should, where possible, be supplied fully assembled
Individually Made
Masks
All previous points apply
ARTP (2017) Association for Respiratory Technology and Physiology (ARTP). ARTP Standards of Care –CPAP Devices (Technical and
Performance).

13. Why mask interfaces?

15. From standard to custom
Personalized 3D-Printed CPAP Masks Improve CPAP Effectiveness.
(2014). 1st ed. [ebook] University Of Michigan.
Fisher & Paykel Forma
Full Face CPAP

16. Optimal design??
http://www.metamason.com/

19. 1- Creating a smart-fit system

20. Two Stages/Cohorts:
• Cohort 1:
Newcastle University (healthy
volunteers)
Study included:
1) 3D Scanning of volunteers Face
2) Mask fitting and comfort
questionnaire
3) Follow up multiple mask fitting
Cohort 2:
• Freeman Hospital (The Newcastle Upon
Tyne Hospitals NHS Foundation Trust)
Study included:
1) Interviews with newly diagnosed patients
2) Interview/questionnaires with recurring
patients
3) Attending clinics at Lung Function
department
Outcomes
▪ Library of 3D digital real facial
features.
▪ Comfort rating of standard masks
▪ Feedback on specific commercial
masks designs
▪ User preferences & expectations

21. User features + User preferences
Is a data-driven system possible?

22. Facial features measurement:
Not an exact science

23. 2- Designing a Bespoke mask
interface

25. Optimized Fit research- 3D modelled mask
Ciaran Doyle (UG)

26. Challenges in Experiment
26
3D facial scanning for volunteer Mask cushion
Scanned 3D facial model of the
volunteer
Scanned 3D model of the
mask cushion

27. Fit / Pressure Simulation
27
Meshing for 3D Dataset Face-Mask Assembly
CPAP Pressure
= 20 cmH2O
Equivalent Stress of MaskTotal Deformation of Mask
High deformation
around nasal
bridge area
High
stress
area

29. Future work avenues
• “Mining” machine learning literature on FR
• Coupling face/image recognition for facial
feature detection for mask design.
• 4D Scanning for complex positioning and
facial tissue displacement tracking
• AI-algorithm for mask fitting/selection based
on facial features

30. Thank you
Acknowledgements:
Work funded by Faculty of Science, Agriculture & Engineering
- Newcastle University
Dr Michael Drinnan (co-supervisor)
Dr Phil Hyde (co-supervisor)
Dr Peter Close (Clinical facilitator at Freeman Hospital)