Based on data from the American Heart Association's (AHA) Get With the Guidelines-Resuscitation (GTWG-R) registry, the incidence of adult treated in-hospital cardiac arrest (IHCA) was about 10 per 1,000 bed-days (290,000 patients per year), and 15 to 20% of adult IHCA patients survived to hospital discharge (i.e., ~80% mortality). Despite the significant morbidity and mortality caused by IHCA, ED-based IHCA is surprisingly less studied. The investigators have utilized electronic medical record (EMR)'s big data (>700,000 visits) from our hospital to investigate, for the first time, the epidemiology and outcome of IHCA in the ED in Taiwan. The investigators also have developed and validated a simple prediction tool for ED-based IHCA, the Emergency Department In-hospital Cardiac Arrest Score (EDICAS). This tool has also been externally validated using Far Eastern Memorial Hospital's ED data. In addition, the investigators also have developed and validated a vital-sign trajectory-based longitudinal model (group-based trajectory modeling [GBTM]) to predict ED-based IHCA.

Based on these studies, the investigators now propose to (1) Embed the EDICAS into our hospital information system (HIS) in real-time at ED triage to identify high-risk patients (EDICAS 6+); and (2) Distribute wearable smart wristbands to high-risk patients to augment vital signs monitoring and send alerts based on GBTM results. The detection and intervention components together form the rapid response system, the Emergency Department In-hospital Cardiac Arrest Response System (EDICARS). In this study, the investigators will enroll and randomize 10 attending physicians into the EDICARS or the usual care arm for 3 months, with each of them treating 100 patients (patients clustered within physicians). The trial will stop for 2 months as a wash-out period, and an interim analysis will be performed. The physicians will then cross over, and each of them will treat 100 patients for another 3 months. A total of 2,000 adult patients will be enrolled. The primary outcome is a composite rate of ED-based IHCA and intensive care unit (ICU) admission. The secondary outcomes include time from ED triage to ED-based cardiac arrest, ICU and hospital length of stay, early ward-based IHCA, and early ICU transfer.

Inclusion Criteria:

• ED patients aged 20 years at recruitment

Exclusion Criteria:

• Inability to sign informed consent;
• Diagnosis of psychiatric disorders that would limit the ability to comply with the study protocol (e.g., wearing a wristband);
• Intending to leave ED against medical advice;
• Already enrolled or planning to enroll in a research study that would conflict with full participation in the study.