Survival after out-of-hospital cardiac arrest in Sydney, Australia.

Background: Out-of-hospital cardiac arrest (OHCA) is a significant cause of death, but there is little published information on its incidence and outcomes in Australia.
Aim: This study was undertaken to determine the incidence and survival from OHCA in Sydney, New South Wales.
Methods: Patients listed on the Ambulance Service of NSW database as having an OHCA during the 12-month period 1 June 2004 to 31 May 2005 were matched with the NSW Registry of Births, Deaths and Marriages to determine if they had died, and how long they survived. Survival was also determined for patients aged 80 years or older, and for the presenting electrocardiograph (ECG) rhythm.
Results: OHCAs were recorded for 2011 people in a population of 3.993 million. The age-standardised incidence was 52.6 events per 100,000 person-years (95% CI, 51.6-53.6). Incidence was significantly higher in older age groups. Only 24% of patients survived past the day of the OHCA. Survival for 28 days, 90 days and 1 year was 12.6%, 12.2%, and 11.5%, respectively. Survival was highest when the presentation ECG was ventricular fibrillation. Patients aged 80 years or older had lower survival rates.
Conclusion: Survival from OHCA in Sydney is low, and lower in patients aged 80 years or older. The incidence of OHCA in Sydney is similar to that in the rest of the world. Mortality occurs early after OHCA. Hence, for interventions to be effective in improving survival, they need to be targeted at the early stages of OHCA.