OUT-of-hospital cardiac arrest (OHCA) is a major public health issue, with an estimated 24 000 Australians suffering an OHCA every year. Moreover, survival from OHCA is low: around 10% of Australians who are treated by emergency medical services will survive to hospital discharge.
We also know that survival is modifiable. Studies from both North America and Europe have demonstrated significant variation in survival between regions. For example, survival to hospital discharge ranged from 1.1% to 30.8% between European countries, suggesting that survival may be associated with service delivery models.
The Victorian Ambulance Cardiac Arrest Registry has been a leader in establishing detailed collection of pre-hospital clinical and operational data since 1999, and has provided critical insights into the treatment and outcomes of OHCA. Likewise, the St John Ambulance Western Australia cardiac arrest registry has also made significant contributions to OHCA research, being the longest standing registry in Australia. Individual registries have been established by ambulance services in most other Australian states and across the whole of New Zealand. However, these registries have not previously been combined and, as a result, little is known about whether regional variation in the incidence and outcomes of OHCA exist in Australia and New Zealand.
The Australian Resuscitation Outcomes Consortium (Aus-ROC) was established as a National Health and Medical Research Council Centre of Research Excellence to increase research capacity aimed at improving outcomes from cardiac arrest. Bringing together ambulance services from Australia and New Zealand has enhanced and informed coordinated OHCA research and evaluation. As part of this, we have established the Aus-ROC Australian and New Zealand OHCA Epistry (epidemiologic registry), which has, for the first time, provided infrastructure to host cardiac arrest data from multiple services and ensure consensus of definitions and standardisation. The Aus-ROC Epistry will enable us to better understand the impact of variability in patient and arrest characteristics, as well as service delivery models between ambulance services on outcomes from OHCA.
Measuring these factors is critical when the rate of change of clinical practice in the pre-hospital setting is accelerating at a pace not seen previously. New evidence on improvements to the system of care and pre- and in-hospital management of OHCA patients is published seemingly daily. As a result of this rate of change, the International Liaison Committee on Resuscitation, a consortium that produces consensus guidelines on emergency cardiac care for basic life support, paediatric life support and advanced life support, have now progressed from reviews every 5 years to a continuous evidence evaluation.
Given this rate of change, there is a need to measure the impact that these changes in clinical practice are having on patient outcomes at a national or binational level, and provide real-world data on the effectiveness of these changes outside of the findings of specific randomised controlled trials. The Aus-ROC Epistry provides us with the infrastructure to measure these impacts.
There is a growing body of evidence questioning the benefit of numerous advanced life support interventions in OHCA, such as anti-arrhythmia drugs and adrenaline. It is evident that going back to basics is a key component to enhancing survival. Patients who receive cardiopulmonary resuscitation (CPR) by bystanders are up to three times more likely to survive than those who do not receive bystander CPR. While rates of bystander CPR have nearly doubled over the past 10 years, 39% of patients who were witnessed to collapse by a bystander did not receive this potentially life-saving intervention. We also know that significant variation in bystander CPR rates exist within regions, and that areas with low rates of bystander CPR also have lower rates of CPR training. This critical factor in cardiac survival is modifiable and continued efforts to train and educate the public on the importance of “any CPR is better than no CPR” and providing good quality chest compressions are warranted. Campaigns such as the international Restart a Heart day are also important in educating the public about CPR skills. However, it is not clear what is driving increased bystander CPR rates and further research is required to identify the most effective approaches in public education.
Technology will also have a growing role to play in improving outcomes from OHCA. Using smartphone technology to dispatch bystanders or people with accredited first aid skills to nearby cardiac arrest cases has been shown to significantly increase bystander CPR rates, and is currently being rolled out in Western Australia and will also be implemented in Victoria in the near future.
Furthermore, early defibrillation is a key factor driving favourable outcomes for patients in a shockable rhythm. Specifically, 55% of patients who are shocked by a public automated external defibrillator (AED) survive to hospital discharge. Continued efforts to increase the number and usage of public AEDs are critical. Smartphone technology to dispatch bystanders should also be able to direct them to the nearest AED and, therefore, improve patient outcomes. To support early access to AEDs, unmanned aerial vehicles, or drones, are a novel method of delivery of AEDs to OHCA cases, and this technology may be introduced into systems of care in the future.
As the systems of care continue to improve and pre-hospital clinical management evolves, we need to ensure that we continue to measure the impact of this rapid change on patient outcomes. To quote Lord Kelvin (1824–1907):
“To measure is to know; if you cannot measure it, you cannot improve it.”
Through the establishment of the Aus-ROC Australian and New Zealand OHCA Epistry, we will facilitate a binational approach to OHCA that will lead to an optimisation of the delivery of care for these patients and will likely improve outcomes from OHCA.
Dr Ben Beck, is deputy head of Prehospital, Emergency and Trauma Research at the Department of Epidemiology and Preventive Medicine, Monash University, Victoria. He writes on behalf of the Aus-ROC Management Committee:
- Prof Judith Finn, Prehospital, Resuscitation and Emergency Care Research Unit, Curtin University, Western Australia
- Prof Peter Cameron, Department of Epidemiology and Preventive Medicine, Monash University, Victoria
- Prof Karen Smith, Centre for Research and Evaluation, Ambulance Victoria, Victoria
- Prof Stephen Bernard, Ambulance Victoria, Victoria
- Prof Hugh Grantham, Department of Paramedics, Flinders University, South Australia
- Dr Cindy Hein, SA Ambulance Service, South Australia
- Dr Janet Bray, Department of Epidemiology and Preventive Medicine, Monash University, Victoria
- Dr Teresa Williams, Prehospital, Resuscitation and Emergency Care Research Unit, Curtin University, Western Australia
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