Understanding the emergency medical service response to patients who are at imminent risk of out-of-hospital cardiac arrest

Study Aim: To understand the survival and emergency medical service call triage and response to patients who suffer an out-of-hospital cardiac arrest after the emergency medical service call is connected. Methods: A descriptive retrospective data analysis of two years’ of out-of-hospital cardiac arrest registry data, 2018-2019, linked to computer aided dispatch data was completed in a single system emergency medical service in the South West of the United Kingdom. Data analysis included descriptive statistics and chi squared analysis for association. Results: There were 4245 out-of-hospital cardiac arrest patients included for analysis. Patients who suffer an out-of-hospital cardiac arrest after the emergency call is connected receive a lower priority response, have a significantly longer response time and where the cardiac arrest is not witnessed by the emergency medical service have poorer outcomes than those patients who have already suffered a cardiac arrest at the time of the emergency call. Conclusion: Emergency medical service response times were significantly shorter for patients who had already suffered a cardiac arrest at the time of the call for help in comparison to those patients who continued to suffer a cardiac arrest after the call for help was connected. Patients who suffer a cardiac arrest after the connection of the emergency call and where the out-of-hospital cardiac arrest is not emergency medical service witnessed have the poorest outcomes.