Development of wheelchair cushion pressure monitoring system

As part of a pressure-relief regimen, individuals with spinal cord injury often rely on air-filled wheelchair cushions to minimize pressure on the body interface and to prevent pressure ulcers. An air-filled cushion is not a stable form of pressure ulcer protection and can effectively be rendered useless if over- or under-inflated. Air loss may happen rapidly and, coupled with loss of sensory feeling and motor movement after spinal cord injury, result in an immediate increase in risk for pressure ulcer development, even with regular pressure relief. Prolonged uneven weight distribution, such as leaning to a side, may lead to “bottoming out” with corresponding increase in risk of pressure ulcers. This paper presents a wheelchair cushion pressure monitoring system that is designed to detect changes in air pressure of a wheelchair cushion as well as body weight and weight distribution. The device is designed to aid both the patient and the caregiver in identifying pressure hazards that may lead to ulcer development and deliver audible and wireless alerts in real time. Inexpensive and low-powered components are used in order to make the device an economical solution. Initial tests demonstrate high sensitivity of the device to potential pressure hazards.