CPR is the artificial maintenance of the respiratory and circulatory systems for a victim of sudden cardiac arrest.  It is performed in hospitals or in the community by Paramedics, firefighters, police officers, emergency trained responders and bystanders.  It is performed by manually pressing on the patient’s chest, compressions, in order to pump blood through the heart and the rescuer exhaling into the patient to inflate the lungs providing further oxygen to the blood, called artificial respiration.  The main purpose of CPR is to maintain blood flow, carrying oxygen to the brain and heart, and delaying biological death to allow for successful resuscitation without permanent brain damage.  CPR is continued until an AED arrives to the scene or advanced life support from Paramedics or medical team in a hospital environment.