It has been found that survival can be improved with each link in the Chain of Survival contributing a different amount. In the first few minutes after a cardiac arrest, caller-dispatcher teamwork can improve survival by a factor of 4. In the next hour, EMS performance of quality CPR can contribute by a factor of 3, and in the following days hospital post-resuscitation care can contribute by a factor of 2. In total, there is the opportunity to increase survival from cardiac arrest by 24-fold.

During the last decades, focus has been on the last two links in the chain -- EMS and hospital care. However, we have learned that survival can be improved dramatically by acting earlier. Early identification of cardiac arrest and better implementation of bystander CPR with dispatcher-assistance results in the greatest impact on survival.