Design and Simulation of a Repositioning Device to Enhance The Quality of Life of Bedridden Patients

Bedridden patients are defined as patients who are confined to the bed due to the inability to move. This leads to a wide range of complications such as pressure ulcers. Pressure ulcers are difficult to heal and require heavy medical attention. A widely used method of treatment is periodical turning of patients by caregivers. This is done to improve blood circulation and decrease the pressure on the skin. The regular turning of the patient causes an increase in caregiver burden. A study has found that 71.1% of caregivers suffer from low back pain as they do their job manually which affects their ability to care for their patients. On the long term, this causes a drastic decrease in the quality of life (QoL) of the patients. Alternative devices to the traditional method of turning are not available in the local market of Palestinian Territories. In this paper, a new design of a repositioning device is presented. The proposed device uses two rollers actuated by electric motors and attached to standard hospital bedding sheets, where the patient lying thereon can be moved as one roller turns. The design is intended to ensure the safety of patients and caregivers, and to fulfill the local market needs. The ease of assembly and disassembly was implemented through design as it improves the quality and reduces costs. The design concept was validated both using hand calculations and Adams simulation software. Both yielded exactly the same results. The device will function properly as long as the sheet moving acceleration does not exceed ≈2650 mm/s^2. Durability is another factor that was considered in the design. A full failure analysis was carried out. Device rollers were identified as the weakest parts. To avoid mechanical failure, a thickness of the rollers was selected. The selection was based on comparing Von Mises stress to the yield strength of materials. To validate the theoretical results, ANSYS simulation was carried out. It showed that a roller of thickness = 5 mm will be durable to expected mechanical loads. The presented design turned out to be sound and functions exactly as required.