Introduction: Since its operation in 2016, the Universitas Sumatera Utara Hospital (USU Hospital) has implemented Medical Services for patients with cardiac arrest conditions by forming a Code Blue team. Based on data in 2018, the number of patients who received the Code Blue emergency was 240 patients. There are still many cardiac arrest events at USU Hospital, it is necessary to evaluate the implementation of the Code Blue services and create an early warning system (EWS) for patients who are potentially in cardiac arrest to prevent high cardiac arrest cases that will economically harm USU Hospital.Method: We analyze the secondary data from the Medical Record, an interview with the code blue team, and an analysis of the resuscitation form that has been completed.Result: The results of the study (n=30) which experienced the most stop breathing and cardiac arrest before the implementation of EWS were chronic diseases with 63.3% (n=19) and after the implementation of EWS there were still chronic diseases with 56.7% (n=17). A paired t-test was conducted with the result that code blue services on the numeric response time parameter was different in response time of 0.266 minutes after the implementation of EWS services (p=0.354). Meanwhile related to the length of time for cardiopulmonary resuscitation(CPR) there is a time difference of 10,767 minutes after the implementation of EWS services, (p=0.000).Conclusion: Interpretation of EWS implementation can affect the time of the CPR performed because the worsening condition of the patient has been monitored before respiratory and cardiac arrest occurred. The conclusion of making an early warning system (EWS) at USU Hospital can be immediately implemented as stated in the guidelines as a form of service in medical and nursing services.