Advanced cardiac life support (ACLS) is a detailed medical protocol for the provision of lifesaving cardiac care in settings ranging from the pre-hospital environment to the hospital setting. ACLS is the appropriate medical response to cardiac arrest and is continued until the person is revived or is declared dead by competent medical authority.
CPR or cardiopulmonary resuscitation is the lowest level of ACLS. CPR provided by laypersons buys time for higher medical responders to arrive and to transport the victim to more advanced medical care. For this reason it is essential that any person starting CPR also activate the emergency medical services by calling for help using the emergency telephone number.
Semi-automatic defibrillation, oxygen and airway support may be provided by emergency medical technicianss.