Incidence and outcomes of out-of-hospital cardiac arrest: A New Zealand perspective.

Abstract

To describe the incidence and outcomes from out-of-hospital cardiac arrest (OHCA) in the New Zealand population served by the St John Ambulance Service. A retrospective observational study was conducted using data from the St John New Zealand OHCA registry, which serves a population of around 4 million. The incidence and outcomes of adult patients who were treated for an OHCA between 1 October 2013 and 30 September 2015 are reported. A total of 7996 adult OHCA cases were attended, resuscitation was attempted in 3862 cases (60 per 100 000 person-years). The median response time was 9 min (interquartile range 7-12), the median age was 66 (interquartile range 53-77) and 69% were men. Most events occurred in the home (67%), bystanders witnessed 53%, EMS witnessed 16% and 31% were unwitnessed. Bystander CPR was administered in 62% of cases and 8% were defibrillated prior to EMS arrival. Most events had a presumed cardiac aetiology (77%) and 38% presented in a shockable rhythm. Of those who had attempted resuscitation, a return of spontaneous circulation sustained to hospital handover occurred in 30% of events and 15% survived to 30 days. Adjusted survival outcomes demonstrated differences according to ethnicity. This is the first study to describe the epidemiology and outcomes of OHCA in New Zealand. Our findings provide important baseline data to monitor temporal trends, investigate the impact of changes in the management of OHCA and demonstrate that there are opportunities for improvement across the system of care.