Association between Scene Time Interval and Survival in EMS-Treated Major Trauma Admitted to the Intensive Care Unit: A Multinational, Multicenter Observational Study

Objective: Major trauma is a major concern in public health and a leading cause of mortality worldwide. This study aimed to evaluate the association between the prehospital scene time interval (STI) and survival in emergency medical service (EMS)-assessed major trauma patients admitted to the intensive care unit (ICU). Methods: A retrospective observational study using the Pan-Asian Trauma Outcomes Study (PATOS) database was conducted. Adult trauma patients with injury severity scores (ISSs) greater than 15 who were admitted to the ICU were selected. EMS STIs were categorized into three groups: short (0-8 minutes), intermediate (9-16 minutes), and long (over 16 minutes). The primary outcome was survival to hospital discharge, and the secondary outcome was good neurological outcome at hospital discharge. Multivariable logistic regression analysis was conducted to calculate odds ratios and confidence intervals, adjusting for age, sex, mechanism of injury, prehospital alertness, prehospital shock index, response time interval, and EMS intervention (airway, oxygen supplementation, and intravenous fluid administration). Sensitivity analysis for patients who underwent surgery or nontraumatic brain injury cases and interaction analysis by EMS intervention were performed. Results: Data from a total of 1,874 eligible patients were analyzed. Intermediate and long STIs showed significant associations with outcomes, with adjusted ORs (95% CI) of 1.21 (1.07-1.38) in the intermediate STI group and 1.74 (1.55-1.96) in the long STI group for survival and 1.37 (1.32-1.40) in the intermediate STI group and 1.31 (1.22-1.41) in the long STI group for neurological outcome. In the sensitivity analysis, the highest ORs were found in the intermediate STI group, with adjusted ORs (95% CI) of 1.40 (1.37-1.42) for survival and 1.32 (1.26-1.38) for neurological outcome. In the interaction analysis, EMS intervention showed a positive interaction effect with an intermediate STI on survival. Conclusion: In EMS-assessed adult major trauma patients admitted to the ICU, we found significant associations between STIs longer than 8 minutes and outcomes. EMS intervention has a positive interaction effect with an intermediate STI on survival. More research is needed to understand the implications of practice for major trauma in the field.