Comprehensive Summary
In their article, Kokeguchi et al. (2025) evaluated the effectiveness of reverse shock index multiplied by Glasgow Coma Scale score (rSIG) for predicting urgent interventions and mortality in patients with isolated severe traumatic brain injury (TBI). This 10-year retrospective validation study analyzed data from the Japan Trauma Data Bank (2012-2021), including 42,375 patients divided into derivation (n=32,483, 2012-2018) and validation (n=9,892, 2019-2021) cohorts. Primary outcomes included the correlation of rSIG with a composite of blood transfusions within 24 hours, craniotomy or craniectomy, intracranial pressure (ICP) monitoring, tracheal intubation, ICU admission, and in-hospital mortality. The optimal rSIG cutoff for predicting urgent interventions was 16.21, while the cutoff for surgical internations was 16.46. For predicting surgical intervention in the validation cohort, rSIG demonstrated an AUC of 0.627 (95% CI 0.614-0.639) with sensitivity of 53.2% and a specificity of 72.1%. Gray-zone analysis identified three risk categories: rSIG ≤6 (high-risk), 6-35 (moderate risk), and ≥35 (low-risk), with the high-risk group showing significantly greater need for urgent interventions and the highest mortality. Based on their findings, researchers conclude that rSIG serves as a simple, rapid predictor of urgent interventions and mortality in patients with isolated severe TBI.
Outcomes and Implications
Each year, approximately 5.48 million people suffer from severe TBI, accounting for around 30% of all trauma-related deaths. While TBI incidence has declined over recent decades, mortality rates remain high, underscoring the need for rapid, accurate triage tools. Existing scoring systems such as the Revised Trauma Score (RTS) multiplied by the Glasgow Coma Scale (GCS) require complex calculations that are impractical in time-sensitive emergency settings. In contrast, rSIG uses only three readily available parameters: heart rate, systolic blood pressure, and GCS score, making it calculable within seconds at the bedside or in prehospital settings. This study validates rSIG as a practical tool for quickly identifying high-risk TBI patients requiring urgent intervention. While promising, the moderate discrimination (AUC 0.627) suggests rSIG should be used as an adjunct to clinical judgement rather than a standalone decision tool. The authors of this study acknowledge limitations such as the retrospective design, reliance on a single national database, and the lack of external validation in non-Japanese populations. Future prospective studies are needed to assess whether rSIG-guided triage improves patient outcomes in real-world trauma systems.