Biomechanical and Physiological Evaluation of Respiratory Protective Equipment Application

Abstract

Purpose

Respiratory protective equipment is widely used in healthcare settings to protect clinicians whilst treating patients with COVID-19. However, their generic designs do not accommodate the variability in face shape across genders and ethnicities. Accordingly, they are regularly overtightened to compensate for a poor fit. The present study aims at investigating the biomechanical and thermal loads during respirator application and the associated changes in local skin physiology at the skin–device interface.

Materials and Methods

Sixteen healthy volunteers were recruited and reflected a range of gender, ethnicities and facial anthropometrics. Four single-use respirators were evaluated representing different geometries, size and material interfaces. Participants were asked to wear each respirator in a random order while a series of measurements were recorded, including interface pressure, temperature and relative humidity. Measures of transepidermal water loss and skin hydration were assessed pre- and post-respirator application, and after 20 minutes of recovery. Statistical analysis assessed differences between respirator designs and associations between demographics, interface conditions and parameters of skin health.

Results

Results showed a statistically significant negative correlation (p < 0.05) between the alar width and interface pressures at the nasal bridge, for three of the respirator designs. The nasal bridge site also corresponded to the highest pressures for all respirator designs. Temperature and humidity significantly increased (p < 0.05) during each respirator application. Significant increases in transepidermal water loss values (p < 0.05) were observed after the application of the respirators in females, which were most apparent at the nasal bridge.

Conclusion

The results revealed that specific facial features affected the distribution of interface pressures and depending on the respirator design and material, changes in skin barrier function were evident. The development of respirator designs that accommodate a diverse range of face shapes and protect the end users from skin damage are required to support the long-term use of these devices.

Keywords:

• respiratory protective equipment
• skin health
• goodness of fit
• interface pressure
• physiological response

Acknowledgments

We would like to thank all individuals who participated in the study.

Disclosure

The authors report no conflicts of interest in this work.

Additional information

Funding

This work was supported by the UK Research and Innovation (UKRI) project “A Bio-Engineering approach for the SAFE design and fitting of Respiratory Protective Equipment (BE-SAFE RPE)” (Ref EP/V045563/1). The authors would also like to acknowledge the EPSRC award for Core Equipment at the University of Southampton (Ref EP/T023880/1). The work was also supported by the EPSRC-NIHR “Medical Device and Vulnerable Skin” Network^PLUS (Ref. EP/N02723X/1).