CPR has been found to be very effective when initiated as soon as possible after the injury (within minutes) and when trained medical professionals arrive within 8 to 12 minutes of the incident. However, persons trained for the same should only institute the procedure. Incorrect CPR technique can result in unintentional harm to the patient.

Chest compressions are performed by applying downward pressure to the chest wall with the hands positioned in a specific way over the sternum (breast bone). When performed correctly, these compressions cause blood to be pumped from the heart to other vital organs.