If breathing has stopped, begin mouth-to-mouth resuscitation. Place the patient on his/her back and follow these steps:
1. To open the airway lift the patient's neck and tilt the head back.
2. Keeping the neck elevated, pinch the nostrils to prevent air leakage.
3. Place your mouth completely around the victim's mouth and blow, watching for chest expansion.
4. After removing your mouth, listen for air leaving the patient's lungs and watch for the chest to fall. Check for an airway blockage if the chest does not rise.

Repeat these steps approximately 12 to 15 times per minute. If treating a child, cover the nose and mouth with you mouth. Use smaller puffs of air and repeat this method 20 to 25 times per minute.