Emergency Medical Individual Clinician Volume and Mortality in Trauma Patients

The initial treatment by emergency medical services (EMS) significantly affects the outcomes for severely injured patients. Effective control of hemorrhage, proper administration of blood products, and adherence to traumatic brain injury guidelines can reduce morbidity and mortality after trauma. Additionally, the experience of prehospital clinicians in high-acuity nontrauma conditions is associated with improved outcomes.

To evaluate the association of annual trauma patient volume and outcomes at the individual EMS clinician level.

A secondary subset analysis was performed of the Linking Investigations in Trauma and Emergency Services (LITES) Task Order 1 study, a prospective observational cohort from 2017 to 2021. It includes severely injured patients, identified by an Injury Severity Score of 9 or higher, who were transported to a trauma center by 1 air and 1 ground agency. Data were analyzed from February 2023 to June 2024.

EMS crew mean 3-year adult trauma volume and 6-hour mortality and several EMS industry quality metrics.

Patient-level risk-adjusted regression models were constructed to determine the association between EMS crew mean 3-year adult trauma volume and 6-hour mortality and several EMS industry quality metrics. The association of airway success metrics and procedural intubation volume was also assessed.

A total of 6769 patient-clinician interactions involving 359 clinicians and 3649 patients (median [IQR] age, 54 [33-70] years; 2490 male [68.2%]) were included in this study. For every increase of 5 adult trauma patients annually per crew, there was a 10% decrease in 6-hour mortality (adjusted odds ratio [aOR], 0.899; 95% CI, 0.811-0.996) and a 2.6% decrease in in-hospital mortality (aOR, 0.974; 95% CI, 949-0.999). In subgroup analyses including traumatic brain injury (aOR, 0.974; 95% CI, 0.949-0.999) and prehospital shock (aOR, 0.974; 95% CI, 0.949-0.999), volume was associated with reduced 6-hour mortality. Highest trauma volume among treating EMS crew members, nontrauma volume, and years of experience were not significantly associated with differences in mortality. Among EMS industry quality metrics, decreasing scene time (regression coefficient, -0.134; 95% CI, -0.191 to -0.077) was significantly associated with higher clinician volume. Intubation procedural volume was associated with greater odds of success without hypotension or hypoxia (aOR, 1.110; 95% CI, 1.040-1.190).

Results of this cohort study suggest that higher patient volumes per EMS clinician were associated with lower early mortality rates after trauma. Exploring this association further is essential to optimize staffing, education strategies, and performance benchmarks.