Reasons why smartphone-alerted first responders abort missions: Findings from a sequential mixed-methods study

Smartphone-based first responder systems are implemented in 209 regions across Germany to reduce time to treatment in out-of-hospital cardiac arrests (OHCA). However, more than 20% of alerted responders abort a mission after accepting the alert. Understanding the underlying reasons is important for improving the prehospital chain of survival.

We conducted a mixed-methods study comprising of (1) semi-structured interviews with smartphone-alerted first responders in Munich to identify and categorise reasons why missions are aborted, and (2) a subsequent quantitative online survey sent to all registered users of the Mobile Retter smartphone app in Munich to determine the frequency of these categories.

Four semi-structured telephone interviews identified six categories with two to three subcodes through qualitative content analysis, which informed questionnaire development. Based on this questionnaire, 334 responder feedbacks were analysed. Among responders, 130 (38.9%) reported aborting a mission after acceptance; 204 had never discontinued a mission. Lack of time advantage over dispatched emergency medical services was the most frequently reported reason for aborting missions (n = 89; 41.8%). An additional 21.6% reported excessive estimated distance, and 12.2% could not locate the emergency site. Further reasons included presumed medically unnecessary alarms and situational unavailability.

Smartphone-alerted first responders were more likely to abort missions due to structural and informational factors rather than safety concerns. Optimising dispatch information, tracking and alert processes, improving emergency site localisation, and refining spatial alerting criteria may reduce discontinued missions and strengthen system effectiveness in urban areas.