Survival of out-of-hospital cardiac arrest (OHCA) is significantly improved by using an external defibrillator and performing cardiopulmonary resuscitation within the first minutes of the arrest (Perkins, Handley, et al., 2015). Dedicated mobile applications enable any bystander of an emergency to report it or to be called to perform first aid on victims (Ciravegna et al., 2016; Garcia et al., 2015). This paper presents the SARA app, which allows call centres to guide the person calling to enact first aid gestures through video. However, even if rescue community recognize the primary role played by citizens in emergencies by the rescue community, barriers still exist to an optimal collaboration. Citizens expressed a fear of hurting the victim and the health professional are reluctant to rely on non-expert. We also have to measure the usability of the app and evaluate the pertinence of video guidance.