For adults, during cardiac arrest, this video shows continuous chest compression can lead to supply of oxygen rich blood to the brain and increase survival chances. One may think that by this method, the patient's chest bones may be broken. But, when he is already in danger, bringing life back is important.
http://www.nidokidos.org/threads/59002-Continuous-Chest-Compression-CPR-Mayo-Clinic-Presentation
CPR for babies: http://www.nidokidos.org/threads/59002-Continuous-Chest-Compression-CPR-Mayo-Clinic-Presentation