Comprehensive Evaluation of User Interface for Ventilators Based on Respiratory Therapists’ Performance, Workload, and User Experience

Abstract

BackgroundPoor ergonomic design of ventilators can result in human errors. In this study, we evaluated the ergonomics of ventilators through respiratory therapists’ performance, workload, and user experience.Material/MethodsSixteen respiratory therapists were recruited to this usability study of 3 ventilators. Participants had to perform 7 tasks on each ventilator. Respiratory therapists’ performance was measured by task errors of all tasks for each participant. Workload was measured by objective measurement (blink rate and duration) and by subjective measurement (NASA-TLX). User experience was assessed by the USE Questionnaire.ResultsFor task errors, significant differences were found among ventilators (p<0.05) and the Evital 4 received higher task errors when compared to the Servo I (p<0.05). For blink rate, significant differences were found in tasks of starting the ventilator, ventilator monitoring values recognition, ventilator setting parameters modification, alarm parameter recognition, and resetting among ventilators (p<0.05). Furthermore, blink duration was also found to be significant differently in tasks of starting the ventilator, mode and setting parameters recognition, ventilator monitoring values recognition, ventilator mode modification, and alarm parameter recognition and resetting, as well as in the average of all tasks (p<0.05). For perceived workload, the Evital 4 received higher NASA-TLX scores among ventilators. For user experience, the Servo I received the highest scores on the USE Questionnaire among the ventilators.ConclusionsThe study provides a comprehensive evaluation method of user interface based on respiratory therapists’ performance, workload, and user experience. In addition, this study suggests that the ergonomic design of the Evital 4 is poor. Finally, we found that eye motion (blink rate and duration) may be useful to assess the ergonomics of a user interface.

Usability testing of radiotherapy systems as a medical device evaluation tool to inform hospital procurement decision-making

“…Published studies have confirmed that a shorter blink duration and a lower blink rate indicate an increasing physiological workload. 15,23,35 Significant differences were also found for blink duration and blink rate between the two radiotherapy systems when cipants performed tasks with these systems. According to the results in Table 3, a longer blink duration (Varian: 0.14 6 0.02, Shinva: 0.12 6 0.03) and a higher blink rate (Varian: 0.45 6 0.37, Shinva: 0.25 6 0.21) were observed for participants with the Varian Trilogy, which means a lower physiological workload was observed for the Varian Trilogy.…”

“…24 Overall, blink rate and blink duration are inversely proportional to the degree of physiological workload. 15,23 Perceived workload. Perceived workload was evaluated based on the NASA Task Load Index (NASA-TLX) questionnaires.…”

“…One common method of evaluating suitability of a system or medical device is performing usability tests. 14 Indeed numerous usability tests have led to modification and improvement of design for several medical devices such as ventilators, 15 infusion pumps, 16 defibrillators, 17 mobile medical ultrasound devices, 18 and laparoscopic devices. 19 Several usability studies on radiation therapy have revealed that poor designs results in human use errors and reduces user performance.…”

Human factors/ergonomics to support the design and testing of rapidly manufactured ventilators in the UK during the COVID-19 pandemic

“…A user evaluation questionnaire was developed based on previous research [10,[12][13][14] to provide a standardised template for gathering the required formative feedback from end users. The questions were checked against the task scenario and professional practice by the clinical authors and adapted to align with the MHRA Specification [5].…”

The usability of ventilator maintenance user interface: A comparative evaluation of user task performance, workload, and user experience

“…The NASA-TLX has been used for assessing the usability of ventilators. 19,21,24 User experience A questionnaire assessing the ease to maintain (1 very difficult to 5 very easy), friendly to maintain (1 very bad to 5 very good) and willingness to use (1 certainly not to 5 certainly) was used to evaluate user experience of the participants. Higher scores indicate a better user experience.…”