Comparison of two emergency response systems and their effect on survival from out of hospital cardiac arrest
Introduction
Out of hospital cardiac arrest continues to have a poor prognosis, with survival rates varying from 2 to 44% [1]. Following collapse, the early assessment of cardiac arrest with alerting of the ambulance crew, bystander CPR, early defibrillation and early advanced life support effect the success of resuscitation [2]. This study examines the role of the first three steps in the chain of survival in two emergency response systems, one in the UK and the other in the USA.
Section snippets
The setting
The UK centre was the Department of Accident and Emergency Medicine, The Royal Infirmary of Edinburgh, Scotland, a university teaching hospital serving a population of 750 000. This department is the only Accident and Emergency Department within Edinburgh, and treats most pre-hospital emergencies. The Emergency Medical Service (EMS), on occasions take patients who have suffered an out of hospital cardiac arrest to the Western General Hospital, a university teaching hospital, but the number is
Methods
Data was collected prospectively from all cardiac arrests treated in both centres for a calendar year. A standard proforma was used based on the Utstein template [3]. The presenting rhythm was obtained from the printout of the semi-automatic defibrillators or from telemetry. Times for pre-hospital events were obtained from the ambulance crews and their record sheets. Outcome parameters were return of spontaneous circulation (ROSC), admission to and discharge from hospital. Arrests caused by
Arrests occurring prior to the arrival of the ambulance crew
Edinburgh treated a total of 306 out of hospital cardiac arrests. In 201 (65.7%) the collapse was witnessed by bystanders. The Milwaukee EMS attended 723 cardiac arrests, but significantly fewer events 181 (25%) (P<0.001) were witnessed. For witnessed collapses, patients in Edinburgh were significantly more likely to receive bystander CPR, 85 (42.3%) compared with 49 (27.1%), P<0.005. Table 1.
The presenting rhythm on initial monitoring at the scene was similar in the two centres. Ventricular
Discussion
The introduction of standardised reporting in the form of the Utstein Template [3]enables meaningful comparison between different centres to be made [4]. Over recent years, research into and appreciation of the factors which improve outcome have resulted in changing practice. The majority of eventual survivors from an out of hospital cardiac arrest come from the group whose presenting rhythm is VF or pulseless VT [5].
If a collapse is witnessed, the likelihood of achieving early access and of
Conclusion
The principle value of comparative health-care studies is to highlight aspects which lead to improvements in outcome. This study indicated that one centre (Edinburgh) achieves a better survival rate for out of hospital cardiac arrest. The main reasons for this improvement appear to be attributable to the greater number of patients whose cardiac arrest was witnessed and in whom bystander CPR was performed.
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