Design and preliminary evaluation of an air-alternating wheelchair seating system for pressure ulcer prevention

Despite the diversity of wheelchair cushions currently used and reported, pressure on bony prominences continues to be a major problem for wheelchair-bound patients, and the incidence of pressure ulcers remains high. This paper introduces a novel air-alternating wheelchair seating (AWS) system for pressure ulcer prevention. The AWS system is composed of 9 separate air chambers, an air pressure sensor MPX2202 and other peripheral control parts. Each air chamber is designed in different size and shape according to the main weight-supporting sites of human buttock and can be inflated and deflated through respective electromagnetic valve under the control of MCU PIC16F877. The AWS system can operate in three basic mode: 1) automatic adjusting mode, 2) manual adjusting mode and 3) air fluid-filled mode and has the potential to improve the prevention of pressure ulcer by alternating supporting site of human buttock either automatically or manually by keyboard manipulating. The preliminary evaluation results of interface pressure measurement showed an obvious pressure relieving characteristic. Further research is needed to evaluate the efficiency of the system in preventing pressure ulcer.