Survival Rates and Determinants of Mortality in Life-Threatening Trauma Patients Transferred via Emergency Medical Services

Abstract

Trauma remains a leading cause of global morbidity and mortality, particularly in life-threatening situations that require immediate medical intervention. Understanding the factors that influence survival outcomes in trauma patients is essential for improving emergency medical services (EMS) and refining trauma care protocols. This study aimed to assess survival rates and identify predictors of mortality among patients with life-threatening trauma transported by Vajira Emergency Medical Services (V-EMS) in Bangkok, Thailand. We conducted a retrospective cohort study utilizing data from V-EMS and hospital records, including patients aged 15 years or older with life-threatening injuries categorized under Response Codes 21-25 and critical emergency levels 1-5, transported to Vajira Hospital between January 1, 2019, and December 31, 2022. Kaplan-Meier survival analysis was employed to estimate survival rates, while Cox proportional hazards regression identified predictors of mortality. The Injury Severity Score (ISS) was also evaluated. Out of 146 patients with life-threatening trauma, 107 survived. The cohort primarily consisted of males, with a median age of 39 years and a median follow-up period of 180 days. The overall median survival time was 120.79 days (95% CI: 65.20-176.38). Survival rates at 30, 60, 90, and 120 days were 63.06%, with a decline to 31.53% at 150 and 180 days. Significant predictors of mortality included male gender (HR_adj = 39.35, 95% CI: 2.76-560.23, p = 0.007), age ≥60 years (HR_adj = 16.24, 95% CI: 2.19-120.30, p = 0.006), pre-hospital systolic blood pressure ≥90 mmHg (HR_adj = 0.10, 95% CI: 0.02-0.45, p = 0.003), severe (ISS 25-49) and critical (ISS 50-74) injury severity scores (HR_adj = 93.92, 95% CI: 1.22-7239.97, p = 0.04; HR_adj = 821.48, 95% CI: 1.16-579279, p = 0.045), and pre-hospital airway management using a bag valve mask (HR_adj = 28.98, 95% CI: 1.92-438.53, p = 0.015). Notably, undergoing a major operation was linked to significantly reduced mortality (HR_adj = 0.04, 95% CI: 0.005-0.28, p = 0.001). This study highlights critical factors affecting survival in patients with life-threatening trauma, emphasizing the necessity of effective EMS and in-hospital care. The results advocate for enhanced EMS training, improved pre-hospital care protocols, and timely surgical interventions to optimize survival outcomes in trauma patients.