The role of bystander CPR in out-of-hospital cardiac arrest: what the evidence tells us.

Out-of-hospital cardiac arrest (OHCA) is a global public health problem. Lay bystanders witness almost half of OHCA, so early recognition is critical to allow immediate initiation of cardiopulmonary resuscitation (CPR) by the bystander. The present investigation aims to analyze the most recent scientific evidence of the effect of bystander CPR on survival after an OHCA.