Design, manufacture, and evaluation of customised CPAP breathing device for the treatment of Obstructive Sleep Apnoea (OSA) syndrome

Abstract

Continuous Positive Airway Pressure (CPAP) therapy has been widely used to treat Obstructive Sleep Apnoea (OSA) syndrome. However, CPAP interface/mask related side effects, such as air leak, noise, skin problem, and discomfort are adversely affecting the overall effectiveness of CPAP treatment. Conventional CPAP interfaces/masks are designed under standard specification, and mass manufactured. Only limited size ranges (Small, Medium, and Large) and simple size templates are offered by CPAP device suppliers to guide patients during interface/mask selection process. Patients worn an ill-fitted interface/mask have a higher chance to suffer side effects during CPAP treatment. This research work aims to overcome the disadvantages presented by conventional CPAP interfaces/masks. In this research work, a thorough study about OSA syndrome, CPAP treatment, and CPAP interface/mask induced side effects were conducted. Questionnaires were developed to better understand how well CPAP interface/mask performs for patients during treatment. To improve the CPAP interface/mask selection process, as an alternative to conventional size templates provided by CPAP device supplier, an advanced interface/mask selection guiding system (namely Smart Fit System) was developed. The aim of developing this system was to allow a better fitted CPAP interface/mask to be selected by carefully considering both human factors and physical characteristics of conventional interface/mask. The combination of Reverse Engineering (3D scanning), 3-Dimensional Computer-Aided Design (3D CAD), and Computational modelling (Finite Element Analysis -FEA) was used to implement the Smart Fit System designed. This research work also attempted to develop customised CPAP interfaces/masks to seek maximum fit and comfort. The customised interfaces/masks were developed by considering the uniqueness of human facial features. In the meantime, other factors, such as clinical requirements and individual preferences can also be considered when necessary. A wide range of advanced digital design tools, including Reverse Engineering (3D scanning), 3D modelling (3D CAD), and Additive Manufacturing (AM) was applied to design and manufacture the customised interfaces/masks. Healthy volunteers were involved to evaluate the performance of these customised interfaces/masks during usability trial. Results showed that customised interfaces/masks performed better than conventional products in terms of fit and comfort.