When rescuing cardiac arrest patient, rescuers should apply CPR and AED jointly (Fig.5-2). For increasing the survival rate of cardiac arrest patient caused by VF, rescuers must make three responses in fist time：1. Activate EMSS; 2. Perform CPR immediately; 3. Rapid deﬁbrillation; which also indicated first three important link of chain of survival.
1. When any rescuer witnesses an out-of-hospital arrest and an AED is immediately available on-site, the rescuer should start CPR and check rhythm, shock if indicated use AED as soon as possible. Repeat defibrillation every 2 minutes CPR.
2. With in-hospital sudden cardiac arrest, the time from VF to shock delivery should be under 3 minutes.
3. For attempted defibrillation of children 1 to 8 years of age with an AED, the rescuer should use a pediatric dose-attenuator system if one is available. An initial dose of 2 J/kg may be considered. For subsequent shocks, energy levels should be at least 4 J/kg; higher energy levels may be considered, not to exceed 10 J/kg or the adult maximum dose.
Fig.Associated application of CPR and AED