Table 1.

Definition of terms and detailed criteria used in this study

Term	Definition
Public location	Street, park, beach or public buildings such as shopping center, sports facility, entertainment center, airport, railway station, church or office building. Cardiac arrest occurred in nursing home facility or ambulance was categorized as non-public location in this study.
Witnessed cardiac arrest	Cardiac arrest witnessed by another person or monitored by EMTs.
Bystander CPR	Any resuscitative effort accompanied by chest compression. Rescue breathing-only effort was excluded.
Time to CPR	Time interval between first recognition of cardiac arrest, witnessed or not, and first attempt of chest compression.
Total duration of CPR	Time interval between first attempt of chest compression and first documented ROSC regardless of its duration.
Initial rhythm	The first rhythm documented by EMTs or ED physician.
Presumed cardiac aetiology	Witnessed sudden collapse suggestive of sudden cardiac death or unwitnessed cardiac arrest without any documented evidence of conditions that might be significantly related with the cardiac arrest such as underlying acute infection, trauma, pulmonary embolism, advanced malignancy, exacerbation of underlying disease, major stroke or bed-bound status.
Sustained ROSC	Documented evidence of return of spontaneous circulation sustained longer than 20 minutes.
Survival discharge	The term “survival discharge” indicates that the patient was discharged to home or long-term care facility, regardless of his or her functional status.
Good neurologic outcome	6-month cerebral performance category score 1–2.

EMT, emergency medical technician; CPR, cardiopulmonary resuscitation; ROSC, return of spontaneous circulation; ED, emergency department.