PREDICTIVE ACCURACY OF SHOCK INDEX VERSUS MODIFIED SHOCK INDEX IN IDENTIFYING SEVERE HEMORRHAGE IN EMERGENCY TRAUMA PATIENTS

Abstract

Severe hemorrhage is a leading cause of preventable early mortality in trauma patients, and rapid identification of those at high risk is essential for timely intervention. Traditional vital signs often fail to detect early circulatory compromise, prompting the use of composite hemodynamic indices such as the Shock Index (SI) and Modified Shock Index (MSI). This study aimed to compare the predictive accuracy of SI and MSI in identifying severe hemorrhage among adult trauma patients presenting to a tertiary-care emergency department. A prospective cross-sectional design was employed, enrolling 240 adult trauma patients aged 18–65 years. Heart rate, systolic and diastolic blood pressure, and mean arterial pressure were recorded at presentation before resuscitation. SI and MSI were calculated, and severe hemorrhage were diagnosed using clinical assessment, transfusion requirements, and need for emergent hemostatic intervention. Diagnostic accuracy was assessed through sensitivity, specificity, predictive values, overall accuracy, and ROC-curve analysis. Severe hemorrhage was identified in 36.2% of patients. Both indices were significantly higher among hemorrhagic patients (SI: 1.33 vs. 0.94; MSI: 1.82 vs. 1.36; p < 0.001). MSI demonstrated superior diagnostic performance with higher sensitivity (86.2%), specificity (79.7%), and overall accuracy (82.5%) compared to SI. ROC analysis showed AUC values of 0.89 for MSI and 0.81 for SI, indicating better discriminative ability for MSI. Subgroup analysis further revealed consistently stronger performance of MSI across both blunt and penetrating trauma. MSI outperformed SI in predicting severe hemorrhage at emergency department arrival, demonstrating higher sensitivity, specificity, and discriminative capability. MSI represents a more reliable early triage tool for hemorrhage identification and may improve timely activation of hemorrhage control pathways in trauma care