Hato Hone St John, CC BY-SAIn New Zealand, ambulance crews treat about seven people a day who are in cardiac arrest, meaning their heart is no longer pumping blood to vital organs. Sadly, fewer than one in eight are likely to survive.But as our new study shows, more lives could be saved if community responders were equipped with portable automated external defibrillators (AEDs) to get treatment to patients sooner.Community responders include bystanders, but New Zealand also uses a smartphone app called GoodSAM to alert volunteers who are trained in cardiopulmonary resuscitation (CPR) and AED use.GoodSAM responders receive alerts about cardiac arrests near their location, allowing them to provide assistance faster, before emergency services arrive. CPR and defibrillation are cornerstones of cardiac arrest treatment, and research shows earlier defibrillation significantly improves survival.Our research shows that when GoodSAMs respond to an alert, the rate of life-saving defibrillation triples for cardiac arrests occurring at home. Community responseMinutes matter in a cardiac arrest. The longer treatment is delayed, the greater the likelihood of permanent injury or death. In New Zealand, an ambulance or fire and emergency services vehicle equipped with a defibrillator reach a patient in cardiac arrest on average eight minutes after an emergency call. In rural areas, the wait can be significantly longer. However, the chances of surviving a cardiac arrest drop dramatically within the first few minutes after collapse.The most recent data from New Zealand’s national out-of-hospital cardiac arrest registry show survival from a cardiac arrest more than doubles when shocks are delivered before the arrival of emergency services. Static defibrillators fixed in a particular location are increasingly available in most communities. But they are rarely used before emergency crews arrive. Only 6% of out-of-hospital cardiac arrest patients receive defibrillation administered by a community responder in New Zealand. Our study found the rate of community defibrillation varies, depending on whether a person’s cardiac arrest occurs in a public space or in their home. Although 72% of all out-of-hospital cardiac arrests happen at home, community responders used defibrillators in only 2% of these cases. In contrast, 15% of cardiac arrest patients in public settings received defibrillation from a member of the community. The use of defibrillators by a community member varies depending on whether a person’s cardiac arrest happens at home or in a public space. Author provided, CC BY-SA Barriers to access of static AEDsCommunity defibrillation doesn’t just depend on bystanders recognising the need for an AED and having the confidence to use it. Rapid access to a device is critical. AEDs are designed to be used by anyone, even if they have received little or no training. But fetching and delivering a static AED to a home-based cardiac arrest patient can be delayed by several barriers, including:lack of awareness of the nearest AED locationdistance to the device or traffic and parking difficultiesdelays in gaining permission to remove the device from the premiseslack of a policy to keep the AED in a rescue-ready condition (with fresh batteries and pads)inaccessibility outside of business hoursand delays in obtaining the code to a locked AED cabinet.Mobile AEDs are becoming more easily available and could significantly improve patient survival. A mobile network of defibrillatorsThe GoodSAM platform has been operating in New Zealand since 2018 and engagement is increasing. Our study shows at least one GoodSAM volunteer accepted an alert for more than 40% of out-of-hospital cardiac arrests, and responders are equally as likely to attend to a patient at home or in a public place.But while they are trained to act and willing to show up, most GoodSAM responders do not carry their own AED. Instead, they face the same challenges to AED access as any other member of the public, and must decide whether a detour to retrieve one will help a person in need or delay other lifesaving care.Fixed public AEDs play a vital and proven role in saving lives. They are especially effective when placed in sports facilities and other locations where large numbers of people gather. But international research shows they are rarely used in residential areas, even when they are located near the address.Mobile AEDs carried by GoodSAM responders could overcome these limitations by extending coverage into home settings. AEDs are now available in smaller, lighter and more portable designs that fit into a backpack. A trial is currently underway to see if GoodSAM responders with ultra-portable AEDs can increase survival rates for patients in cardiac arrest.Mobile defibrillators may have an even larger impact in rural areas where ambulances have longer response times. A small US study in a rural community compared 15 AEDs assigned to community responders with 66 AEDs in fixed locations. Over a 12-month period, none of the static AEDs were used, but the AEDs assigned to responders were deployed 19 times. Our research demonstrates that mobile defibrillators could dramatically improve early access to lifesaving treatment when people suffer a cardiac arrest in their home – and improve their chances of survival.Sarah Maessen also works for Hato Hone St John.Heather Hutchinson also works for Hato Hone St John.Bridget Dicker does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.