In Northern Ireland there is only approximately a 10% chance of surviving an out-of-hospital cardiac arrest (OHCA). The British Heart Foundation Northern Ireland states that every minute without CPR and defibrillation reduces the chance of survival by up to 10%. However, in some cases, early CPR and defibrillation can more than double the chances of survival. Therefore, having a firm understanding of CPR and the confidence to operate a defibrillator correctly can be crucial in an emergency.