The Development and Protocol for Testing a Co-Created Digital Intervention (Sentinel) to Improve Mental Wellbeing and Help Manage and Prevent Trauma in First Responders and Frontline Workers. (Preprint)
Authors: Kirk Alison , Cogan Nicola , Graf Christoph 
Published: February 2025

BACKGROUND

First responders (FRs), including firefighters, police officers, paramedics, and emergency healthcare workers, as well as other frontline workers, are frequently exposed to traumatic events as part of their professional roles. This exposure places them at heightened risk of experiencing acute stress, post-traumatic stress disorder (PTSD), burnout, and other adverse mental health outcomes. Despite growing awareness of these risks, there remains a lack of evidence-based digital interventions (DIs) specifically tailored to meet the unique mental health needs of FRs and frontline workers.

OBJECTIVE

This study aims to address this gap by developing and testing Sentinel, an evidence-based, co-created DI designed to promote mental wellbeing, build resilience, and help manage and prevent trauma among FRs and frontline workers. The objectives include exploring their experiences of occupational trauma, identifying their preferences for digital mental health tools, and evaluating the feasibility of the Sentinel intervention.

METHODS

The development of Sentinel followed a rigorous, four-phase approach. In phase 1, we conducted a market analysis and in-depth qualitative interviews with 54 FRs from fire services, police, and emergency healthcare sectors. The aim was to explore their mental health needs, barriers to accessing support, and views on the potential role of DIs in addressing these needs. In phase 2, we developed the content for Sentinel by integrating findings from phase 1 with existing evidence, policies, and theoretical frameworks, ensuring the intervention reflected the lived experiences of FRs. In phase 3, a high-fidelity clickable prototype of Sentinel will be tested through a series of co-design workshops, iterative development sprints, and usability evaluations. Feedback from FRs and frontline workers during this phase will refine the app's design and functionality. Phase 4 involves a mixed-methods, non-randomised feasibility study to evaluate Sentinel’s acceptability, usability, safety, and implementation potential. Quantitative data will be collected from up to 100 FRs, complemented by qualitative interviews with 30 FR participants and 20 health and social care professionals who refer FRs to the intervention.

RESULTS

The co-creation process has proven essential in ensuring Sentinel meets the specific needs of FRs and frontline workers. Preliminary feedback highlights the app's relevance and usability. The feasibility study will provide detailed insights into its potential effectiveness, inform refinements, and determine readiness for a larger efficacy trial.

CONCLUSIONS

Sentinel represents a novel, personalised digital solution designed to address the unmet needs of FRs and frontline workers exposed to occupational trauma. This feasibility study will evaluate its capacity to improve mental wellbeing, support trauma recovery, and build resilience. Findings will guide future refinements and the transition to a fully powered efficacy trial.