Acute cardiac care & resuscitationCohort study

How to Measure First Responders’ Arrival Time in a Smartphone Alerting System? An observational study

ResuscitationPublished

  • observational study

Authors' conclusion

GPS-based tracking provides a reliable, objective measure of CFR arrival times. The 50m geofence offers the highest practical applicability and consistency. Manual confirmation was often delayed or missing, limiting its reliability. GPS50m could be considered a standardized metric for arrival measurement in SAS for further evaluation and optimization. (DRKS00032957, 30/10/2023).

Study context

Population
Activations of the Smartphone Alerting Systems (SAS) "Region of Lifesavers" in Freiburg, Germany, over a 12-month period (1/12/2023–30/11/2024)alerts, 2,480 community first responders (CFR) accepted, 1,577 complete data cases
Participants
1,498 participants
Exposure
GPS100m vs GPS50m vs manual confirmation

Main finding

As reported in the abstract

Median arrival time

GPS100m

04:21

median · IQR 02:58, 06:00 · min

GPS50m

04:40

median · IQR 03:19, 06:25 · min

manual confirmation

05:50

median · IQR 04:03, 08:04 · min

Significant differences between all methods
P < 0.001 for all pairwise comparisons

Observational data: associations, not effects.

Further findings

Manual confirmation documented

Manual confirmation documented
69.2%

Bland-Altman analysis

Smaller bias for GPS50m than for GPS100m, with comparable limits of agreement

Original publication

How to Measure First Responders’ Arrival Time in a Smartphone Alerting System? An observational study. Resuscitation. Published 25 September 2026. doi:10.1016/j.resuscitation.2026.111329

Summarised from the published abstract; every number is checked against it