Clinical Predictors and Resuscitative Care Indicators of Early Mortality Among Adult Major Trauma Patients Transported by Emergency Medical Services in Thailand

Introduction: Early identification of high-risk trauma patients in the prehospital setting is critical for optimizing emergency care and improving outcomes, particularly in resource-limited systems. Purpose: To determine the 24-hour mortality rate and identify clinical predictors and resuscitative care indicators associated with early mortality among adult major trauma patients transported by emergency medical services (EMS) in Thailand. Methods: A retrospective registry-based cohort study included adult patients (≥ 18 years) with major trauma transported by EMS to a tertiary trauma center in Bangkok between January 2019 and December 2024. Eligible patients were classified under Thailand Emergency Medical Triage Protocol symptom groups 21– 25 with red-level severity. Data were obtained from an EMS-based trauma registry integrating prehospital and early in-hospital variables. The primary outcome was all-cause mortality within 24 hours of hospital arrival. Survival was analyzed using Kaplan–Meier methods, and predictors were identified using multivariable flexible parametric survival models. Results: Among 197 patients, the 24-hour mortality rate was 25.9% (95% CI: 20.3– 32.6). Severe neurological impairment (Glasgow Coma Scale 3– 8) was independently associated with mortality (adjusted hazard ratio [aHR] 3.72, 95% CI: 1.56– 8.87). Resuscitative care indicators, including chest tube insertion (aHR 6.82, 95% CI: 3.23– 14.39) and central venous catheter placement (aHR 2.50, 95% CI: 1.21– 5.17), were also associated with mortality and likely reflect underlying injury severity and physiological instability rather than direct causal effects. The model demonstrated good discrimination (C-statistic 0.848) and calibration. Conclusion: One in four adult major trauma patients transported by EMS died within 24 hours of hospital arrival. Early mortality was associated with both clinical severity and resuscitative care indicators. These findings support the use of routinely available clinical variables to identify high-risk patients and inform early triage and escalation of care, while emphasizing cautious interpretation of care-related variables as markers of severity rather than modifiable risk factors. Keywords: major trauma, emergency medical services, clinical predictors, prehospital care, resuscitative care