Latent Safety Threats During Simulated Internal Mass Casualty Incidents: A Multicenter Simulation-Based Systems Testing Study.

INTRODUCTION

Internal mass casualty incidents (MCIs) challenge hospital systems by requiring rapid coordination across clinical, operational, and communication domains. Simulation-based clinical systems testing (SbCST) can identify latent safety threats (LSTs), but cross-institutional patterns in internal MCI preparedness remain poorly characterized.

METHODS

We conducted a multicenter simulation-based systems assessment using in situ SbCST and Failure Modes and Effects Analysis (FMEA) during simulated internal MCIs. LSTs were identified through triangulation of structured field observations, facilitator observations, and participant self-report during debriefing. Observations were consolidated through structured review, categorized into system-level domains using the HFMEA (Healthcare Failure Mode and Effect Analysis) framework by multidisciplinary consensus, and prioritized using FMEA with expert scoring followed by consensus reconciliation.

RESULTS

Approximately 75-80 raw observations yielded 53 unique LSTs across 2 hospitals. Recurrent vulnerabilities involved leadership, patient flow, communication, triage, and system interfaces. A substantial proportion were classified as high or very high priority, with comparable median FMEA scores across sites (Site 1: 30 [IQR 24-36]; Site 2: 32 [IQR 24-48]). Mitigation strategies were proposed for approximately 60-65% of LSTs.

CONCLUSION

Multicenter SbCST identified recurrent, high-priority system-level vulnerabilities across 2 hospitals. Prospective tracking of mitigation implementation and re-simulation are needed to determine whether identified threats are reduced over time.