Our research group is engaged in various projects focused on app-based first responder systems and AED networks. The 2021 international guidelines recommend implementing such systems to minimise the time to first chest compressions and defibrillation.
It is now clear that technology makes the difference. Many community first responder systems use radial distances, meaning all registered responders within a certain straight-line distance (for example, within 1,000 metres) of the emergency location are alerted. However, we know that the straight-line distance between a responder and the emergency site often correlates poorly with actual response times. This can lead to disadvantages: some responders may be physically close in terms of distance but travelling on foot, taking longer to reach the patient than the ambulance. Others may be further away but travelling by car, potentially arriving much sooner.
Therefore, modern alerting algorithms are needed to identify first responders, locate them via an app using GPS technology, and select those who will arrive fastest — ideally before the emergency services.
Our research adheres to the international reporting standard for first responder systems, ensuring a reliable data foundation for research and quality assurance.
The findings from our studies provide the basis for the continuous improvement of the Region of Lifesavers system.
Julian Ganter, Simon Mei, Jan-Steffen Pooth, Thomas Brucklacher, Georg Trummer, Hans-Joerg Busch, Michael Patrick Mueller:
Turnout Time in Smartphone Alerting Systems:
Underestimated Entity in the Development of Smartphone-related Dispatch Algorithms
Resuscitation 2025 RESUS 110772
Julian Ganter, Ariane-Catherina Ruf, Stefan Bushuven, Ute Nowotny-Behrens, Michael Patrick Müller, Hans-Jörg Busch:
Psychological impact on first responders dispatched to out-of-hospital cardiac arrest via smartphone alerting system:
A longitudinal survey-based study
Resuscitation Plus 2025; 23:100941
Metelmann C, Metelmann B, Müller MP et al.:
Defining the terminology of first responders alerted for out-of-hospital cardiac arrest by medical dispatch centres: An international consensus study on nomenclature.
Resuscitation Plus 2025; 22:100912
Ganter J, Busch HJ, Trummer G, Schmitz D, Pooth JS, Steuber T, Brucklacher T, Müller MP:
Von der Smartphone-basierten Ersthelferalarmierung zum "Lebensrettenden System".
Notfall Rettungmed 2024; doi.org/10.1007/s10049-024-01395-2
Müller MP, Ganter J, Busch HJ, Trummer G, Sahlmann J, Brettner F, Reden M, Elschenbroich D, Preusch M, Rusnak J, Katzenschlager S, Nauheimer D, Wunderlich R, Pooth JS:
Out-of-Hospital cardiac arrest & SmartphonE RespOndErS trial (HEROES Trial): Methodology and study protocol of a pre-post-design trial of the effect of implementing a smartphone alerting system on survival in out-of-hospital cardiac arrest.
Resuscitation Plus 2024; 17:100564
Ganter J, Ruf A, Oppermann J, Feilhauer J, Brucklacher T, Busch HJ, Müller MP:
Automatic measurement of departing times in smartphone alerting systems: A pilot study
Resuscitation Plus 2024; 17:100510
Müller MP, Metelmann C, Thies KC, Greif R, Scquizzato T, Deakin CD, Auricchio A, Barry T, Berglund E, Böttiger BW, Burkart R, Busch HJ, Caputo ML, Cheskes S, Cresta R, Damjanovic D, Degraeuwe E, Ekkel MM, Elschenbroich D, Fredman D, Ganter J, Gregers MCT, Gronewald J, Hänsel M, Henriksen FL, Herzberg L, Jonsson M, Joos J, Kooy TA, Krammel M, Marks T, Monsieurs K, Ng WM, Osche S, Salcido DD, Scapigliati A, Schwietring J, Semeraro F, Snobelen P, Sowa J, Stieglis R, Tan HL, Trummer G, Unterrainer J, Vercammen S, Wetsch WA, Metelmann B:
Reporting standard for describing first responder systems, smartphone alerting systems, and AED networks
Resuscitation 2024; 195:110087
Müller MP, Jonsson M, Böttiger BW, Rott N:
Telephone cardiopulmonary resuscitation, first responder systems, cardiac arrest centers, and global campaigns to save lives
Current Opinion in Critical Care 2023; 29:621-627
Metelmann B, Baldi E, Beckers SK, Burkart R, Fredman D, Ganter J, Krammel M, Marks T, Metelmann C, Müller MP, Scquizzato T, Stieglis R, Strickmann B, Thies KC:
Proposal to increase safety of first responders dispatched to cardiac arrest.
Resuscitation Plus 2023; 14:100395
Jonsson M, Berglund E, Müller MP:
Automated external defibrillators and the link to first responder systems.
Current Opinion in Critical Care 2023; 29:628-632
Eder PA, Soda H, Kuhle B, Dodt C, Dormann H, Popp E, Flasch B, Müller MP, Böhmer M, Kerber S, Barth S, Krämer R, Kraus M, Purrucker JC, Oberhoff M, Hans FP, Stäblein H, Brammen D, Gilmore S, Deneke T, Wehler M, Rashid A:
Digitales Notfallmanagement im Netzwerk der Akut- und Notfallversorgung. Eckpunktepapier des Expertenrats des ZTM.
Notfall Rettungsmedizin 2023; DOI: doi.org/10.1007/s10049-23-01241-x
Damjanovic D, Pooth JS, Steger R, Boeker M, Steger M, Ganter J, Hack T, Baldas K, Biever PM, Schmitz D, Busch HJ, Müller MP, Trummer G, Schmid B:
Observational study on implications of the COVID-19-pandemic for cardiopulmonary resuscitation in out-of-hospital cardiac arrest: qualitative and quantitative insights from a model region in Germany.
BMC Emergency Medicine 2022; 22:85
Ganter J, Damjanovic D, Trummer G, Busch HJ, Baldas K, Steuber T, Niechoj J, Müller MP:
Implementierungsprozess einer Smartphone-basierten Ersthelferalarmierung.
Notfall- und Rettungsmedizin 2022; 25:177-85
Ganter J, Pooth JS, Damjanovic D, Trummer G, Busch HJ, Baldas K, Schmitz D, Müller MP:
Association of GPS-based logging and manual confirmation of the first responders´ arrival time in a smartphone alerting system: An observational study.
Prehospital Emergency Care 2022; 26:829-37
Metelmann C, Metelmann B, Müller MP, Böttiger BW, Trummer G, Thies KC:
First responder systems can stay operational under pandemic conditions: Results of a European survey during the COVID-19 pandemic
Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine 2022; 30:10
Metelmann C, Metelmann B, Herzberg L, Auricchio A, Baldi E, Benvenuti C, Burkart R, Fredman D, Krammel M, Müller MP, Scquizzato T, Stieglis R, Svensson L, Thies KC:
More patients could benefit from dispatch of citizen first responders to cardiac arrests.
Resuscitation 2021; 168:93-4
Müller MP, Damjanovic D, Ganter J, Trummer G:
Comment on “Mobile phone-based alerting of CPR- trained volunteers simultaneously with the ambulance can reduce the resuscitation-free interval and improve outcome after out-of-hospital cardiac arrest: A German, population-based cohort study”.
Resuscitation 2021; 158:286-287
Metelmann C, Metelmann B, Kohnen D, Brinkrolf P, Andelius L, Böttiger BW, Burkart R, Hahnenkamp K, Krammel M, Marks T, Müller MP, Prasse S, Stieglis R, Strickmann B, Thies KC:
Smartphone-based dispatch of community first responders to out-of-hospital cardiac arrest – statements from an international consensus conference
Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine 2021; 29:29
Ganter J, Damjanovic D, Trummer G, Busch HJ, Baldas K, Hänsel M, Müller, MP:
Smartphone based alerting of first responders during the corona virus disease-19 pandemic
Ganter et al. Medicine (2021) 100:27
