Table 1.

Key parameters.

Variables	Parameters
Demographic variable	Age Sex Nationality Country Presenting hospital Comorbidities
Peri–cardiac arrest variables	Location Witnessed status Bystander CPRa AEDb use EMSc arrival time Initial rhythm Prehospital shocks Prehospital CPR time
Post–cardiac arrest variables	ROSCd Survival to discharge Neurological outcome at discharge Neurological outcome at 3 months

^aCPR: cardiopulmonary resuscitation.

^bAED: automated external defibrillator.

^cEMS: emergency medical services.

^dROSC: return of spontaneous circulation.