Abstract 54: A Study of the Effectiveness of Public Access Defibrillation in Urban and Rural Populations in Northern Ireland: The Northern Ireland Public Access Defibrillation Study
Background: In Belfast City, 78% of Out-of-Hospital Cardiac Arrests (OHCAs) occur in the home and are not amenable to Public Access Defibrillation (PAD) with Automated External Defibrillators (AEDs) in public places. This study examined mobile AEDs in urban and rural populations.
Methods: The urban (NWB) and rural (NN) areas each had populations of approximately 140,000. In year 1 (2004) we prospectively assessed the demographics of OHCA, including Call to Response Interval (CRI) for the Emergency Medical Services (EMS). In year 2 (2005) we deployed mobile AEDs, 29 in NWB and 42 in NN. In NWB 327 First Responders (FRs), (267 lay, 60 police) and in NN 417 FRs, (347 lay, 70 police) were trained in AED use. Over 60% of FRs had CPR training. In year 2 FRs were dispatched to OHCAs via Automated Internet Paging (AIP) in conjunction with the EMS.
Results: In NWB, year 1 there were 159 OHCAs, mean EMS CRI 7 min (SD 3), initial rhythm Ventricular Fibrillation (VF) 28 / 159 (18%), 22% witnessed and survival rate 5%. In year 2 there were 154 OHCAs, VF 19 / 154 (12%), FRs were paged to 151 events and attended 113 / 151 (74.8%), 20 / 151 (13.2%) were reached before the EMS. Mean combined CRI for year 2 was 5 min 49 sec (SD 3 min). We can be 95% confident that the mean improvement in CRI by the addition of FRs is >12 sec but the mean CRI was not significantly improved. In year 2 survival rate was 3.2%, (p=0.75). In NN, year 1 there were 131 OHCAs, mean EMS CRI 11 min (SD 6), VF 19 / 131 (14.5%), 34% witnessed and survival rate 2.3%. In year 2 there were 93 OHCAs, VF 14 / 93 (15%), FRs were paged to 69 events and attended 59 / 69 (85.5%), 28 / 69 (40.6%) were reached before the EMS. Mean combined CRI for year 2 was 7 min 40 sec (SD 4 min). We can be 95% confident that the mean improvement in CRI by the addition of FRs is >61 sec and the mean CRI was significantly improved, (p=0.021). In year 2 survival rate was 5.4 %, (p=0.11). In both areas FRs attended 172 events, reaching 48 (27.9%) before the EMS. Only 2 / 48 (4.2%) were VF arrests, 95.8% non shockable.
Conclusion: Mobile FRs improve the CRI in urban and rural areas with a significant impact in the rural area. There was no impact on survival despite a high percentage of events being reached first by the FRs due to a low incidence of VF. Dispatch by AIP represents a novel method of AED delivery.