Highlights
An increase of just five adult trauma patients annually per EMS clinician is associated with a 10% decrease in 6-hour mortality and a 2.6% decrease in overall in-hospital mortality.
Higher clinician volume correlates significantly with reduced scene times, suggesting greater procedural efficiency and clinical decision-making speed.
Increased intubation procedural volume is linked to higher success rates without the common complications of hypotension or hypoxia.
Interestingly, total years of experience and nontrauma patient volume were not significant predictors of trauma survival, highlighting the importance of trauma-specific repetitions.
Background: The Critical First Minutes of Trauma Care
The initial moments following severe traumatic injury—often referred to as the ‘golden hour’—are the most critical for patient survival. Emergency Medical Services (EMS) clinicians are the front-line providers whose actions during these minutes dictate long-term outcomes. Evidence-based interventions such as rapid hemorrhage control, the administration of blood products, and adherence to specialized traumatic brain injury (TBI) guidelines have been proven to reduce morbidity. However, the delivery of these complex interventions is highly dependent on the skill and experience of the individual clinician.
While the volume-outcome relationship is well-established at the hospital level—where high-volume trauma centers consistently outperform low-volume facilities—less is known about this relationship at the individual clinician level in the prehospital setting. This study aims to fill that gap by evaluating whether the number of trauma patients an individual EMS clinician treats annually affects patient mortality.
Study Design and Methodology
Researchers performed a secondary subset analysis of the Linking Investigations in Trauma and Emergency Services (LITES) Task Order 1 study. This prospective observational cohort spanned from 2017 to 2021 and focused on severely injured patients transported to trauma centers by both air and ground agencies. The study population included 3,649 patients with an Injury Severity Score (ISS) of 9 or higher, involving a total of 6,769 patient-clinician interactions across 359 clinicians.
The primary exposure measured was the EMS crew’s mean 3-year adult trauma volume. Outcomes were assessed using patient-level risk-adjusted regression models. The primary endpoints included 6-hour mortality, in-hospital mortality, and various EMS industry quality metrics, such as scene time and airway management success.
Key Findings: Does Volume Translate to Survival?
The data revealed a striking association between clinician volume and patient survival. For every increase of five adult trauma patients treated annually per crew member, there was a 10% decrease in 6-hour mortality (adjusted odds ratio [aOR], 0.899; 95% CI, 0.811-0.996). Furthermore, this volume increase was associated with a 2.6% decrease in overall in-hospital mortality (aOR, 0.974; 95% CI, 0.949-0.999).
Subgroup Analysis: TBI and Shock
In high-stakes scenarios such as traumatic brain injury and prehospital shock, the benefits of clinician volume remained consistent. In both subgroups, higher volume was significantly associated with reduced 6-hour mortality. This suggests that the ‘stress-inoculation’ or procedural fluency gained through frequent trauma exposure is particularly vital when managing physiologically unstable patients.
Procedural Success and Efficiency
Beyond mortality, the study examined process-of-care metrics. High-volume clinicians were notably more efficient, with decreasing scene times (regression coefficient, -0.134) significantly associated with higher clinician volume. In terms of airway management, increased intubation procedural volume was associated with greater odds of ‘first-pass success’ without the deleterious effects of hypotension or hypoxia (aOR, 1.110; 95% CI, 1.040-1.190).
The Experience Paradox
One of the most intriguing findings was that neither the highest trauma volume among a crew, nor the total years of experience, nor the volume of nontrauma cases significantly affected mortality. This suggests that ‘experience’ is not a static trait acquired over decades, but rather a perishable skill maintained through recent, high-frequency trauma-specific practice.
Expert Commentary and Clinical Implications
The findings of Beiriger et al. underscore a critical challenge in modern EMS systems: skills decay. In many jurisdictions, EMS clinicians may go weeks or even months without treating a severely injured trauma patient. This study provides a data-driven argument for reassessing how EMS agencies assign staff and maintain competency.
From a policy perspective, these results suggest that trauma care might benefit from a ‘regionalized clinician’ model, similar to how trauma centers are regionalized. By concentrating trauma exposure among specific teams or increasing the use of high-fidelity simulation for low-volume clinicians, agencies may be able to bridge the gap in mortality. Additionally, the lack of correlation between nontrauma volume and trauma survival implies that a busy EMS clinician is not necessarily a proficient trauma clinician unless their caseload specifically includes high-acuity trauma.
Conclusion
This cohort study demonstrates that individual EMS clinician trauma volume is a significant predictor of early mortality in severely injured patients. As the medical community looks toward optimizing the ‘prehospital’ phase of trauma care, focusing on clinician-level performance benchmarks and volume-based staffing strategies will be essential. Future research should explore whether targeted educational interventions or simulation-based training can replicate the survival benefits observed in high-volume clinicians.
Funding and ClinicalTrials.gov
This study was supported by the Linking Investigations in Trauma and Emergency Services (LITES) consortium. Data analysis was conducted between February 2023 and June 2024. ClinicalTrials.gov Identifier: NCT03195322.
References
Beiriger J, Martin-Gill C, Silver DS, et al. Emergency Medical Individual Clinician Volume and Mortality in Trauma Patients. JAMA Surg. 2026 Feb 18:e256741. doi: 10.1001/jamasurg.2025.6741. Epub ahead of print. PMID: 41706461.
