Modeling and Simulating Combat Casualty Throughput in Civilian Health Care Facilities

Introduction: This study is part of the congressionally mandated NDMS Pilot Project, which evaluates civilian healthcare system readiness to manage up to 1,000 daily combat casualties per day over 100 days. It aims to simulate patient throughput for high-casualty scenarios in the National Capital Region (NCR). Researchers designed a simulation model to assess healthcare resource allocation, patient flow, and throughput constraints across NCR NDMS-enrolled facilities. Methods: The simulation was built in Simio™ software. Random iterations of 204 detailed casualty case types were used to create a segment of the daily national casualty load, reflecting the varied injury types and medical needs projected in the setting of near-peer conventional war. The simulation matches patients to “adequate Healthcare Facilities (HCF)” with appropriate specialties and bed types. A Decision Support System was developed for patient assignment, incorporating real-time capacity assessments through telemedicine links. Each simulation run involved 100 replications across 100 days, capturing patient metrics for minimal, average, and maximum patient journey times. A sensitivity analysis examined differences in casualty types and other simulation parameters. Results: The NDMS Bethesda-FCC simulation scenario managed approximately 49% throughput, with significant wait times for Med/Surg and ARU beds, highlighting constraints in specialty care. Expanding the Bethesda-FCC model to include 13 additional Baltimore FCC facilities improved throughput to 62%, with average patient time-in-system reduced by 21.7%. Sensitivity analyses demonstrated that increased bed capacity and rapid discharge to post-acute care facilities significantly enhanced patient throughput. Conclusion: This study underscores the challenges of managing sustained high-casualty surges within the current NDMS structure, identifying critical gaps in specialty care resources and post-acute care capacity. Expanding NDMS facility networks and enhancing discharge pathways could substantially improve patient throughput. This model offers a foundational tool for NDMS planning, with implications for optimizing patient and resource distribution and improving regional medical response to high-casualty situations.