Mouth-to-mouth rescue breathing is typically performed after a person has stopped breathing due to cardiac arrest or an airway obstruction. It is a technique used to force air into a persons lungs and is very effective in delivering oxygen into the persons lungs without putting the rescuer at a high level of risk. The indication for mouth-to-mouth rescue breaths is when a persons heart stops beating, leading to cardiac arrest.

When performing mouth-to-mouth rescue breaths, it is important to open the airway using the head-tilt/chin-lift maneuver, pinch the persons nose closed with your hand on the persons head, create a seal when using your lips to surround the persons mouth, and blow into the persons mouth for one full second while watching for the chest to rise. If the chest does not rise, tilt the victims head further back and give an additional breath for over one second. It is important not to give breaths too rapidly or too forcefully, as this may cause air to be forced into the stomach, resulting in distention and less room for lung expansion, or cause vomiting.

It is worth noting that rescue breathing is sometimes required, but mouth-to-mouth CPR is no longer advised for untrained bystanders in certain circumstances, such as toddlers and infants experiencing cardiac arrest due to a non-cardiac reason, almost drowning, drug overdoses, choking, poisoning, asthma episodes, and carbon monoxide poisoning.