BLS, or "basic life support," refers to basic life-saving techniques including hands-only cardiopulmonary resuscitation (Hands-Only CPR) and the Heimlich maneuver.
ACLS, or "advanced cardiac life support," translates to "advanced cardiac life support," and refers to the application of assistive devices and special techniques (such as cardiac arrest and resuscitation) while continuing BLS on the basis of BLS. The term "advanced cardiac life support" refers to the use of assistive devices and special techniques (e.g., cardiac monitoring, defibrillators, artificial respirators, and medications) to establish and maintain more effective ventilation and circulation while continuing BLS on the basis of BLS.
And PALS, or "pediatric advance life support", which translates to "pediatric advanced life support", refers to the advanced life support technology applied to pediatric patients. PALS is different from ACLS because of the many differences between the physiology and anatomy of children and adults.