Enhancing the Usability of Patient Monitoring Devices in Intensive Care Units: Usability Engineering Processes for Early Warning System (EWS) Evaluation and Design

<b>Background/Objectives</b>: This study aimed to enhance the usability of patient monitoring systems by integrating the Early Warning Score (EWS) function and improving user interface elements. The EWS function is expected to enable the early detection of acute deterioration and prompt medical intervention, while the optimized design supports rapid decision-making by nursing staff. <b>Methods</b>: Two formative usability evaluations were conducted to identify user requirements and improve the device design. A simulated usability test involved five ICU medical staff members, followed by a user preference survey with 72 ICU staff members in a real clinical setting. After incorporating feedback, a summative usability test with 23 ICU nurses was performed to evaluate the revised device. <b>Results</b>: Issues related to unfamiliar parameter terminology and alarm message positioning were identified, and the need for the EWS function was emphasized. The summative evaluation showed an increase in task success rate from 86% to 90% and a significant improvement in user satisfaction from 74.85 (SD: 0.88) to 89.55 (SD: 0.75) (<i>p</i> < 0.05). <b>Conclusions</b>: The integration of the EWS function and interface improvements significantly enhanced the usability of patient monitoring system. These advancements are expected to enable rapid detection of patient deterioration and support timely clinical decision-making by ICU staff.