Abstract for: Improving trauma care in low- and middle-income countries: exploring interventions across the four delays framework

Traumatic injury is a leading cause of mortality and disability globally, with a disproportionate burden in low- and middle-income countries (LMICs). Many deaths are preventable but occur due to systemic barriers across the trauma care pathway. The Four Delays framework identifies key stages where failures occur in seeking care, reaching facilities, receiving treatment, and accessing rehabilitation. This study develops a simulation model of trauma care delivery structured around the Four Delays framework. The model represents patient flows from injury through transport, treatment, and rehabilitation while incorporating behavioural factors and capacity constraints. Simulation experiments are used to explore how interventions targeting different delays influence system congestion, mortality, and disability outcomes. The results show that interventions targeting individual delays can produce unintended system effects. Improving transport accessibility increases hospital arrivals and can worsen treatment congestion when hospital capacity remains limited. In contrast, expanding rehabilitation capacity substantially reduces long-term disability, highlighting the importance of post-acute care in trauma system performance. The findings highlight the importance of addressing multiple stages of the trauma care pathway simultaneously. Interventions focusing on a single delay may shift bottlenecks rather than improve outcomes. The analysis demonstrates the value of systems approaches for understanding trauma care dynamics and supporting coordinated policy interventions to strengthen trauma systems in LMICs. Some model formulations, estimation of some constants values. designing the scenarios