Evaluating the usability of a wristband for automated cardiac arrest detection and alerting

Abstract Background Survival from unwitnessed out-of-hospital cardiac arrest (OHCA) remains poor due to delayed activation of the emergency medical response. Wearable technology with automated cardiac arrest detection and alerting may offer a solution to this problem. The DETECT-project focuses on developing a wristband that incorporates this functionality. Assessing usability early in the development process increases the likelihood of successfully implementing this technology in the future. This study evaluates the usability, defined as user experience and loyalty towards the device, of a wristband being developed for automated cardiac arrest detection. Purpose The aim of this study is to assess the usability of a wristband being developed for automated cardiac arrest detection in adult participants included in the DETECT-3 study, using the Usability Metric for User Experience (UMUX) questionnaire and Net Promotor Score (NPS). Methods This is a preliminary analysis of data of the DETECT-3 study (full analysis results will be available at the ESC congress), a prospective observational study in adult volunteers who wear the CardioWatch wristband (version 287-2) for a period of two months to assess false positive cardiac arrest alarms. At the final study visits, participants complete the UMUX questionnaire and NPS. The UMUX results in a score ranging from 0 to 100, with higher scores indicating better usability. The NPS results in one overall score for the entire group between -100 and 100, in which 0 and above indicates a positive perception. The scores were calculated for the entire group, for healthy participants, and for the potential target group for this technology, including patients with an ICD, history of myocardial infarction, cardiomyopathy, heart failure with reduced ejection fraction, or positive family history of sudden cardiac death. Results A total of 152 participants were included in this analysis. The mean (standard deviation) age of the participants was 57 (16) years, and 85 (54%) were men. The overall median UMUX score was 83 (IQR 75-92). Participants within the potential target group (n=53) and healthy participants (n=99) had similar median UMUX scores of 88 (IQR 75-96) and 83 (IQR 75-92) (p-value 0.22), respectively. The overall NPS score was 23, with scores of 26 for participants within the potential target group and 21 for healthy participants. The UMUX and NPS questions and the answers given by participants are depicted in Table 1 and Figure 1. Conclusions Participants generally rated the usability of the wristband for automated cardiac arrest detection and alerting positively. No significant differences in scores were seen between healthy participants and participants within the potential target group, suggesting that the device is equally user-friendly across different user groups. These findings will be used to further develop the technology.Table 1.UMUX questionnaire Figure 1.NPS