The first step in providing first aid to a person who is unconscious and not breathing is to check for a pulse. If there is no pulse, start chest compressions.

The recommended rate for chest compressions during CPR is 100-120 compressions per minute.

The recommended ratio of chest compressions to rescue breaths during CPR is 30:2.

The recommended depth for chest compressions during CPR is 2 inches (5 cm).

The proper hand position for chest compressions during CPR is to place one hand on the center of the chest and the other hand on top of the first hand, interlacing the fingers.

You should continue CPR until help arrives, even if the person starts breathing or their pulse returns.

The most common cause of sudden cardiac arrest is a heart attack.

The signs and symptoms of a heart attack can include chest pain or discomfort, shortness of breath, nausea or vomiting, and pain in the arms, back, neck, or jaw.

If you think someone is having a heart attack, you should call 911 immediately, give the person aspirin, and loosen the person's clothing.

The most common cause of choking is food, but toys, coins, and other small objects can also cause choking.

The signs and symptoms of choking can include difficulty breathing, coughing, wheezing, and a bluish tint to the skin.

If someone is choking, you should give the person the Heimlich maneuver and call 911.

The Heimlich maneuver is a series of abdominal thrusts that are used to dislodge a foreign object from a person's airway.

To perform the Heimlich maneuver on an adult, you should stand behind the person and wrap your arms around their waist, place your hands on the person's stomach, just below the rib cage, and give the person a series of quick, upward thrusts.

To perform the Heimlich maneuver on a child, you should stand behind the child and wrap your arms around their waist, place your hands on the child's stomach, just below the rib cage, and give the child a series of quick, upward thrusts.