During your patient rounds, you find an unresponsive 78-year old woman. From across the room, your first impression of the patient is that she is not moving, you can see no rise and fall of her chest or abdomen, and her skin color is pale. When you arrive at the patient's side, you confirm that she is unresponsive. As you shout for help, your next action in this situation should be ________.
1) Open the airway and check breathing
2) Begin chest compressions
3) Check breathing and a pulse
4) Apply the AED