RESUMO
AIMS: Out-of-hospital cardiac arrest (OOHCA) survival remains poor, estimated at 3-7%. We aim to describe the incidence of OOHCA, survival from OOHCA, and the impact of improved pre-hospital care on survival from OOHCA. METHODS AND RESULTS: A retrospective registry was established using multi-source information to assess survival from cardiac arrest following the introduction of several improvements in pre-hospital emergency medical care from 2003. Survival from OOHCA, from asystole/pulseless electrical activity, and from ventricular tachycardia/ventricular fibrillation was estimated. Adjusted per 100 000 population annual incidence rates from national population census data were calculated. Mean and median emergency medical services (EMS) response times to OOHCA calls were assessed. A total of 962 OOHCAs occurred from 1 January 2003 until 31 December 2008. Sixty-nine per cent (69%, n = 664) were male. Seventy-two per cent (72%, n = 693) occurred at home with 28% occurring in a public venue. Of these public venues, 33.9% (91 of 268) had an automated external defibrillator available. Bystander cardiopulmonary resuscitation (CPR) was in progress when emergency services arrived in 11% (n = 106) of the cases. Nineteen per cent (19.4%, n = 187) had a known prior cardiac history or chest pain prior to circulatory collapse. Overall survival to hospital discharge improved significantly from 2.6 to 11.3%, P = 0.001. Survival from ventricular fibrillation (VF) to hospital admission, rose from 28.6 to 86.3%, P = 0.001. Survival to hospital discharge from VF improved from 21.4 to 33%, P = 0.007. Mean EMS response times to the scene of arrest decreased from 9.18 to 8.34 min. Emergency medical services scene time, reflecting acute pre-hospital medical care, rose from 14.46 to 18.12 min. The adjusted incidence of OOHCA for our catchment population declined from 109.4 to 88.2 per 100,000 population between 2003 and 2008. CONCLUSIONS: The incidence of OOHCA has declined but importantly, survival to hospital discharge has improved dramatically. Reduction in ambulance response time, resulting in earlier initiation of basic and advanced life support and earlier defibrillation, was associated with an increase in the proportion of victims found in VF rather than asystole and likely accounted for most of the improvement. Further improvements in response times and public education to improve bystander CPR rates should remain a priority.