Ergonomic Evaluation and Design Process for Healthcare Products: A Case Study of Patient Transfer Design

Abstract

Inpatient falls are a critical issue in healthcare facilities. Up to 30% of such falls result in injury, which may in turn lead to impaired rehabilitation and co-morbidity in mental and physical health. One of routine activities that poses high risks of falls of patients is a within-facility patient transfer. Within-facility patient transfer is a high-risk task not only for patients but also for care-givers. Care-givers frequently transfer patients from bed to a wheelchair or wheelchair to bed manually, and it can cause musculoskeletal injuries of the care-giver. Various aid devices such as a powered patient lifter have been introduced to improve the safety of patient transfer and to assist care-givers, but they have not been widely used due to their bulky size and slow operation. To overcome such problems, one of medical robot manufacturers in Korea developed the functional prototype of a semi-powered patient lift and transportation device. The device is equipped with a forward leaning seat to allow easy loading and unloading patients without manual lifting. Since the functionality and usability of the prototype has not been evaluated, it was necessary to conduct thorough evaluation both in fields and laboratory and to come up with redesign goals and strategies. Therefore, this study was aimed to evaluate the functionality and usability of the prototype using various ergonomic evaluation approaches and to redesign the prototype based on the results of the evaluation. In the evaluation process, various methods have been used to understand and identify care-givers’ needs, interaction patterns between the prototype and patients, and safety issues when operating the prototype inside and outside patient rooms through user interview and field observation studies at hospitals. To evaluate the biomechanical advantages over traditional manual transfer methods, a human-subject experiment was also conducted with quantitative assessment of muscle activities, foot reaction forces and transfer time. Then, using the findings of the evaluation, redesign ideas have been made and the prototype has been upgraded to reflect the ideas. The upgraded prototype was evaluated again at hospitals to confirm whether the changes improved the functionality and usability of the device. In this paper, detail procedures for the evaluation and redesign are explained, with related problems and challenges. Also, some ideas for improving the evaluation/redesign processes for healthcare products are proposed for future research and development.