## 3 Results
### Flow of Services  
An app user who is a patient or caretaker launches this app and registers using his or her e-mail and password after consent of privacy (Figure 4A). After login, the main page shows the user's picture, name, blood type, drug allergies, and recent visits to the ED at a glance. Additionally, there are four items linked on the main page: details of medical records from recent ED visits, medication that has to be taken today, \"My recent health condition\", and recent self-checked blood pressure. Additionally, there is an SOS button to directly call the patient's care provider on the top left and a plus-shaped button that included items associated with the ED records at the bottom right (Figure 4B). When the user inputs \"My recent health condition\", the most recent record is displayed on the main page. The user can choose a part of the body that is uncomfortable and add a note. In the same way, a record of self-checked blood pressure is shown. The systolic and diastolic blood pressures can be entered separately (Figure 4C). Upon touching a button labeled \"I have to take medicines today\", the screen displays the hospital and department, day, medication and dosage, and frequency prescribed. Each medication button is linked to a page with a description of it (Figure 4D). Figure 3: System and server architecture for FirstER. Data transmission and reception between the hospitals and the MyData cloud servers were linked by RESTful API, SSL, and JSON. A patient sends his or her hospital ID to the HIS through the private cloud platform when the patient agrees to subscribe to the mobile app and the collection/use of their personal information. After validation of the subscriber information, the ED core data of the patient are extracted from the HIS server to the MyData-linked server in the hospital. Afterwards, when a patient requests “download”, the core data of the patient are transferred from the connected server in the hospital to the MyData cloud platform (OS: operating system, ED: emergency department, SSL: Secure Socket Layer, ID: identification, IaaS: Infrastructure as a Service, DMZ: demilitarized zone, WAS: web application server, WWW: World Wide Web, URL: uniform resource locator, PC: personal computer, HIS: hospital information system). To use the functions of the EMR-tethered PHR, the user touches the plus-shaped button on the main page and then touches the \"Download\" button. When the user selects the hospital and inputs the hospital ID number, the existence of newly generated data is checked and any such data are downloaded. Downloaded data are displayed as a button labeled \"I went to the ED several days ago\" on the main page. When the user touches the button, details of the ED records from the EMR system of the selected hospital are seen. The user can see the time of the visit and discharge from the ED, diagnosis, department, results of blood and urine tests, and medications prescribed at discharge. If the user has several ED visit records, the user can press the \"List\" button at the bottom and check each entry (Figure 4B,E). When the button labeled \"Emergency ID\" in the plus-shaped button on the main page is touched, it shows at a glance the information--namely, the patient's name, gender, age, blood type, drug allergies, hospitals recently visited, caretaker information, and a document on the decision to withdraw from life-sustaining treatment--that is needed immediately in an emergency situation (Figure 4D). Upon touching a button labeled \"disclosure\" in the plus-shaped logo on the main page, the user enters his or her password for authentication and then selects the institution and items to share. After that, the user sends a temporary URL (limited to 24 h) of their previous ED records via SNS or e-mail (Figure 4D). By adding a function of selecting the institution and items to share in his or her medical record to the fundamental setting function, the user can choose whether to share sensitive medical information.