Relative Mortality Analysis Of The "Golden Hour": A Comprehensive Acuity Stratification Approach To Address Disagreement In Current Literature.

OBJECTIVE: This study sought to address the disagreement in literature regarding the "golden hour" in trauma by using the Relative Mortality Analysis to overcome previous studies' limitations in accounting for acuity when evaluating the impact of prehospital time on mortality. METHODS: The previous studies that failed to support the "golden hour" suffered from limitations in their efforts to account for the confounding effects of patient acuity on the relationship between prehospital time and mortality in their trauma populations. The Relative Mortality Analysis was designed to directly address these limitations using a novel acuity stratification approach, based on patients' probability of survival (PoS), a comprehensive triage metric calculated using Trauma and Injury Severity Score methodology. For this analysis, the population selection and analysis methods of these previous studies were compared to the Relative Mortality Analysis on how they capture the relationship between prehospital time and mortality in the University of Virginia (UVA) Trauma Center population. RESULTS: The methods of the previous studies that failed to support the "golden hour" also failed to do so when applied to the UVA Trauma Center population. However, when applied to the same population, the Relative Mortality Analysis identified a subgroup, 9.9% (with a PoS 23%-91%), of the 5,063 patient population with significantly lower mortality when transported to the hospital within 1 hour, supporting the "golden hour." CONCLUSION: These results suggest that previous studies failed to support the "golden hour" not due to a lack of patients significantly impacted by prehospital time within their trauma populations, but instead due to limitations in their efforts to account for patient acuity. As a result, these studies inappropriately rejected the "golden hour," leading to the current disagreement in literature regarding the relationship between prehospital time and trauma patient mortality. The Relative Mortality Analysis was shown to overcome the limitations of these studies and demonstrated that the "golden hour" was significant for patients who were not low acuity (PoS >91%) or severely high acuity (PoS <23%).

Trauma Survival Margin Analysis: A Dissection of Trauma Center Performance through Initial Lactate.

Measurement of trauma center performance presently relies on W-score calculation and comparison to national data sets. A limitation to this practice is a skewing of the W score, as it determines overall performance of a trauma population that is often heavily weighted by patients of low acuity. The University of Virginia relative mortality metric (RMM) was formulated to provide higher resolution in identifying areas of performance improvement within subpopulations of a trauma center using traditional Trauma Injury Severity Score methodology. Lactic acidosis has been established as a risk factor for mortality in the setting of trauma. This study aims to compare survival margin, defined as the area between actual and predicted mortality curves, in patients with either normal or elevated initial lactate. W score and RMM were calculated and compared in these cohorts. Whereas the W score suggested increased survival within the high initial lactate group, the RMM demonstrated the expected finding of increased survival margin in the normal lactate cohort. The RMM is a potentially valuable tool for trauma centers to monitor and improve performance. In addition, these findings validate the use of lactate as a triage and risk adjustment tool in the trauma setting.