Moving the dial on out-of-hospital cardiac arrest survival in Aotearoa New Zealand

Out-of-hospital cardiac arrest (OHCA) remains one of the most time-critical medical emergencies in Aotearoa New Zealand. The Hato Hone St John Out-of-Hospital Cardiac Arrest Registry reports that 2,192 adults received resuscitation attempts in 2024/2025 where an ambulance was sent, with 11% surviving to 30 days.¹ Hato Hone St John provides ambulance services across New Zealand, except for the Greater Wellington and Wairarapa Regions, which are served by Wellington Free Ambulance.

Survival has remained largely unchanged over the past 5 years despite improvements in prehospital practice. Survival in the Utstein comparator group with a shockable rhythm is 29%, comparable with similar ambulance systems internationally, but overall system improvements remain modest.¹ The Utstein comparator group provides a common set of guidelines for standarised OHCA reporting and includes patients over the age of 15, all causes, a resuscitation was attempted, the patient presented with a shockable rhythm and the OHCA was witnessed by a bystander.

International evidence consistently demonstrates that early intervention is the strongest determinant of survival.² Registry data show that bystander cardiopulmonary resuscitation (CPR), community defibrillation and activation of community responders through the GoodSAM first-responder network are consistently associated with higher rates of survival.¹ GoodSAM, or Good Smartphone Activated Medics, is a platform used internationally as well as in New Zealand to support registered volunteer activation to an OHCA by emergency services. Yet only 6–7% of patients receive community defibrillation prior to ambulance arrival.^1,3 Given that survival decreases by approximately 10% for every minute defibrillation is delayed,³ the interval before ambulance arrival represents the most critical opportunity for improvement.

Seventy-two percent of cardiac arrests occur at home,¹ highlighting the importance of family members and bystanders as first responders.

While 81–83% of witnessed arrests receive bystander CPR,^1,3 access to publicly available defibrillation remains limited. Audits have demonstrated that many automated external defibrillators (AEDs) are often not accessible 24 hours a day or are inaccurately registered.³ Strategic placement of AEDs and distribution of portable AEDs to first responders where a response may be limited or in areas of deprivation and high case incidence is essential. Options for AED use and availability have significantly improved and a number of ultralight defibrillator options are now on the market, improving portability and general use.

Significant inequities persist. Registry data demonstrate higher OHCA incidence among Māori, Pacific peoples, rural populations and those living in high-deprivation areas. Lower survival odds are observed among Māori, Pacific peoples, females, rural residents and individuals in high-deprivation communities.¹ Females have 60% lower odds of receiving community defibrillation compared with males.¹ International evidence confirms that socio-economic deprivation influences outcomes as well as equitable access to post-resuscitation care.²

Any strategy to improve survival must be equity focussed and engage communities to explore potential solutions. While this may initially focus on the equitable distribution of AEDs and education, we should also think more broadly about enabling volunteer first-response networks from and for the community they serve. International examples such as Hatzolah in Australia may provide an example of a framework to adapt first-response models to community needs while maintaining cultural safety.⁴

Mandatory CPR and AED training in schools represents one of the most scalable long-term interventions available and was a topic of discussion in a recent New Zealand Medical Journal article and subsequent correspondence. Children aged 13–14 years can perform effective chest compressions, and younger children can be taught to recognise emergencies and activate help.³ The World Health Organization has endorsed CPR education in schools for more than a decade.³ Countries that have implemented national CPR initiatives, such as Denmark, have substantially increased bystander CPR rates and improved survival.²

New Zealand already benefits from strong voluntary education programmes, including St John in Schools and community-based training initiatives.¹ However, more can be done. Embedding CPR and AED training within the national curriculum would ensure universal exposure and build generational resilience. Given that most cardiac arrests occur in the home, equipping all school leavers with CPR competency has the potential to transform the national response capacity.

Education is one part of a wider, integrated system. An effective national strategy should include: 1) mandatory CPR and AED education in schools; 2) targeted AED deployment supported by a national defibrillator registry; 3) strengthened community-responder programmes such as GoodSAM; 4) equitable access to appropriate clinical facilities for post-arrest care; and 5) embedding a quality-based system to continually learn from and improve ambulance and prehospital clinical practice and performance.²

OHCA survival in Aotearoa New Zealand has plateaued at approximately 11%.¹ Registry data and international evidence clearly demonstrate that early community response is the strongest modifiable determinant of survival.²

Strengthening the foundations through universal CPR education, community-led first-response networks and equitable AED access offers a realistic pathway to improving outcomes. Smoke alarms in homes are now ubiquitous. Will an AED in every school, community centre or home be thought of in the same way? Will we be willing to leave AED cabinets unlocked for ease of access? Moving the dial on cardiac arrest survival will require co-ordinated national action across education, health and community sectors.