Cardiac arrest occurs suddenly and unexpectedly. It is a condition where the pulse and breathing are absent. In adulthood, cardiac arrest is mostly the consequence of heart disease. In order to treat such patients more successfully, cardiopulmonary resuscitation (CPR) is needed as early as possible. The role of the layman is important so that the resuscitation can start as soon as possible, and with the ambulance they make the right team for a more successful KPR. The aim of this paper is to express the percentage of success of the KPR branch office Sv. I. Zelina, which belongs to the Institute of Emergency Medicine of the Zagreb County. Branches that are still grading in that county are Samobor, Velika gorica, Zaprešić, Jastrebarsko, Vrbovec, Dugo Selo, Ivanić Grad and Zelina. The study was conducted on 90 patients from January 2015 to December 2019. They were enrolled in the e-Emergency program, conducted through the Utstein form, which we, with consent, filtered the data and later interpreted in the paper. The aim of the research was to show whether younger people are subject to more successful KPR, whether using Lucas the outcome was better. I also wanted to express the importance of lay resuscitation and their education in order to perform KPR as well and as well as possible. The paper describes how healthcare workers in an outpatient emergency room should be organized and professional, how unpredictable situations await us, and how we should be constantly vigilant. The course of resuscitation is described, how we should educate ourselves regularly and be vigilant for ourselves and the whole team.