We provided complete mechanical engineering and industrial design for Defibtech’s Lifeline ARM Automated Chest Compression device. It performs mechanical chest compressions when effective manual CPR is not possible. Effective cardiopulmonary resuscitation (CPR) requires a high level of excellence in order to have an impact on the survival rate of a cardiac arrest victim. This is very difficult to achieve manually when fatigue can occur in as little as 1-2 minutes while trying to maintain at least 2 inches/5 cm depth compressions at a minimum rate of 100 compressions per minute.