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This is a plain English summary of an original research article. The views expressed are those of the author(s) and reviewer(s) at the time of publication.

A smartphone app called GoodSAM sends alerts to first aiders when someone nearby has had a cardiac arrest (their heart stopped beating). Research found that, when a first aider responds to the alert, the person’s chances of survival doubled.

Survival rates are poor among people who have a cardiac arrest when they are not in hospital. Only 1 in 10 of these people survive to hospital discharge. Timing is critical; every minute’s delay in restarting the heart reduces the chance of survival.

GoodSAM is one of several apps that alert first aiders, and it is available around the world. In the UK, ambulance services have integrated the GoodSAM app into their systems. When they receive a call for a suspected cardiac arrest, the app sends an alert to users within a certain distance. Users must have a first aid or professional healthcare qualification.

Researchers looked at the numbers of people who survived until they were discharged, following an out-of-hospital cardiac arrest. The study, in London and the East Midlands, showed that people were twice as likely to survive when an alert was sent than when it was not (for instance if no nearby first-aiders were registered to the app).

The researchers say that more needs to be done to increase the number of app users.

More information about cardiac arrests is available on the London Ambulance Service website.

What’s the issue?

Cardiac arrest means that someone’s heart stops pumping blood around the body. Each minute without intervention decreases the person’s chances of survival by 10%. Emergency services in England reach half (54%) of callouts for a cardiac arrest in 7 minutes. If a passer-by performs first aid (cardiopulmonary resuscitation, CPR) or uses an automated external defibrillator (to deliver an electric current to restart the heart), more people survive.

Several apps have been developed to alert volunteer first aiders about nearby cardiac arrests. GoodSAM is one such app that is available internationally. Anyone can download the app, but to register, people must hold a valid CPR qualification or professional healthcare qualification (such as medical doctor, nurse or paramedic).

In the UK, Australia and New Zealand, GoodSAM is integrated into ambulance services. When an emergency call handler suspects a cardiac arrest, they activate the app. It sends an alert to app users within a certain distance of the incident. If they accept the alert, the app gives them the best route to the person in need of help. Ambulance crews still attend, whatever the response to the app.

Researchers explored whether use of the GoodSAM app is linked to a better chance of survival after an out-of-hospital cardiac arrest. The study was carried out in London and the East Midlands, which were among the first 2 regions to adopt the app.

What’s new?

Data on outcomes after out-of-hospital cardiac arrests and ambulance service involvement is routinely collected in a national registry. This study analysed London data over a period of 1 year, when there were 4,196 emergency calls for out-of-hospital cardiac arrests. East Midlands data covered 1,001 emergency calls over 6 months.

The GoodSAM app automatically sent an alert every time there was a first aider within a set distance of the person with cardiac arrest. In London, this distance is 300 metres; in East Midlands, it is 800 metres.

In London, there was a volunteer within range for 7% of calls. 1 in 6 (16%) alerts were accepted by GoodSAM users, and:

  • 1 in 10 (10%) people survived until they were discharged from hospital when an alert was not sent
  • twice as many (18%) survived when an alert was sent and accepted.

In the East Midlands, there was a volunteer within range for 23% of calls. Again, 1 in 6 (15%) alerts were accepted by GoodSAM users, and:

  • 1 in 14 (7%) people survived until they were discharged from hospital when an alert was not sent
  • twice as many (15%) survived when an alert was sent and accepted.

The researchers accounted for age, gender, ambulance service response time, and other factors that could influence survival. After these adjustments, the study found that people were 3 times more likely to survive (in both locations) when responders accepted an alert.

Why is this important?

Survival rates after an out-of-hospital cardiac arrest are poor (10% or lower). Survival is more likely when a GoodSAM alert was accepted (than when it was not sent).

The success of the app depends on people being registered. Currently, GoodSAM has around 40,000 registered users, but that figure is small considering it is global. In this study, the app could only send alerts out in 7% (London) and 23% (East Midlands) cases because of the lack of people nearby who were registered.

The GoodSAM app only allows people with a CPR qualification or medical qualification to register. The researchers say that increasing the numbers of people registered would improve the success of the app in future.

The researchers caution that the study did not look at what the responder did when they arrived, and those actions ultimately improve survival. Further research is needed to confirm these findings, and to investigate which factors influence survival. The researchers would like to replicate the study in different areas and to look at long-term survival and outcomes for people having an out-of-hospital cardiac arrest. However, those data are not currently collected.

What’s next?

The app is low cost, and efforts to make it as effective as possible are likely to be worthwhile. However, rates of response to the alert were low in this study. Only around 1 in 6 (15-16%) users accepted alerts.

This could have been because people with their phone in silent mode did not hear the alert. The team behind the app have since updated it, so that people can opt for the alarm to override silent mode.

People could be concerned about the implications of accepting an alert. But previous studies showed that app users rarely reported anxiety about responding to an alert. A few reported an impact on their psychological health, but this had usually resolved within 4 – 6 weeks or was mild.

The researchers say that it is not clear whether apps such as GoodSAM are more effective in improving survival than other strategies. Community responses could also be strengthened by improving the population’s knowledge of first aid. To that end, first aid is now being taught in schools.

People using the GoodSAM app were often reluctant to find an automatic external defibrillator before going to the person in need. They may have been uncertain where the nearest devices were (though defibrillator locations are listed on a freely accessible website). In addition, not all devices are easily reached and accessed; they may be locked away or high up.

You may be interested to read

This Alert is based on: Smith CM, and others. The effect of the GoodSAM volunteer first-responder app on survival to hospital discharge following out-of-hospital cardiac arrest. European Heart Journal: Acute Cardiovascular Care 2022;11:20–31.

A paper exploring the development of the app and its use in London: Smith CM, and others. The use of trained volunteers in the response to out-of-hospital cardiac arrest – the GoodSAM experience. 2017;121:123-126. Available at:

An NIHR Evidence Alert looking at the distribution of automatic external defibrillators

Resources including information about CPR from the Resuscitation Council UK

Lifesaver is an interactive app that can teach people CPR skills and how to use an automated external defibrillator

Website with more information about the GoodSAM App

Funding: NIHR Doctoral Research Fellowship (DRF-2017-10-095).

Conflicts of Interest: Some authors are employed by University of Warwick which hosts the Out-of-Hospital Cardiac Arrest Outcomes registry; some have received funding from the British Heart Foundation and the Resuscitation Council UK. Full details can be found on the original research.

Disclaimer: NIHR Alerts are not a substitute for professional medical advice. They provide information about research which is funded or supported by the NIHR. Please note that views expressed in NIHR Alerts are those of the author(s) and reviewer(s) at the time of publication. They do not necessarily reflect the views of the NHS, the NIHR or the Department of Health and Social Care.

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