Design of an Alternating Pressure Overlay for the Treatment of Pressure Ulcers

This paper discusses the development of an alternating pressure overlay designed with miniaturized air cells for the treatment of pressure ulcers. Pressure ulcers can be identified as a skin deformity due to application of prolonged pressure on the skin causing improper blood circulation. The alternating behaviour of the air cells aid in pressure relieving, thus provide better blood circulation to carry vital nutrients to the tissues while reducing formation of pressure ulceration. The proposed design miniaturizes the air cell sizes and establish an optimum air cell size to provide high-resolution pressure therapy in comparison to existing designs. This optimum air cell size, geometry along with its 3D deformation profiles were analysed using finite element method. The findings of the numerical simulations concluded that individual cell design should contain a minimum cell membrane thickness of 5mm and an overlay height of 185mm to withstand a maximum pressure of 60mmHg. Optimum pressure pattern of the alternating pressure therapy was selected as 1-in-4 pressure pattern, where the pressure overlay was divided into five pressure zones to actuate and map the interface pressures required. The control system was designed to provide required alternating pressure for patients by detecting the high pressure zones.