Basic Cardiac Life Support (BCLS) or cardiopulmonary resuscitation (CPR) refers to the skills required (without use of equipment) in the resuscitation of cardiac arrest individuals. On recognising cardiac arrest, chest compressions should be initiated. Good quality compressions are with arms extended, elbows locked, shoulders directly over the casualty's chest and heel of the palm on the lower half of the sternum. The rescuer pushes hard and fast, compressing 4-6 cm deep for adults at 100-120 compressions per minute with complete chest recoil. Two quick mouth-to-mouth ventilations (each 400-600 mL tidal volume) should be delivered after every 30 chest compressions. Chest compression-only CPR is recommended for lay rescuers, dispatcher-assisted CPR and those unable or unwilling to give ventilations. CPR should be stopped when the casualty wakes up, an emergency team takes over casualty care or if an automated external defibrillator prompts for analysis of heart rhythm or delivery of shock.