The use of the Shock Index as a predictor of active bleeding in trauma patients

Abstract

Introduction: Vital signs indicate the presence of bleeding only after large amounts of blood have been lost, with high morbidity and mortality. The Shock Index (SI) is a hemorrhage indicator with a cut-off point for the risk of bleeding at 0.9. The aim of this study is to assess whether a cut-off of≥0.8 is more sensitive for detecting occult bleeding, providing for early initiation of therapeutic maneuvers.

Methods: SI analytical validation study of severe trauma patients older than 16 years of age. Vital signs were recorded, and scales for predicting bleeding included: SI, Assessment of Blood Consumption score, and Pulse Rate Over Pressure score. The relationship between the SI and 5 markers for bleeding was analyzed: need for massive transfusion, angiographic embolization, surgical bleeding control, death due to hypovolemic shock, and the overall predictor «active bleeding» (defined as the presence of at least one of the 4 markers above).

Results: Data from 1.402 trauma patients were collected prospectively over a period of 10 years. The mean Injury Severity Score was 20.9 (SD 15.8). The mortality rate was 10%. The mean SI was 0.73 (SD 0.29). «Active bleeding» was present in 18.7% of patients. The SI area under the ROC curve for «active bleeding» was 0.749.

Conclusions: An SI cut-off point≥0.8 is more sensitive than≥0.9 and allows for earlier initiation of resuscitation maneuvers in patients with occult active bleeding.

Keywords: Blood transfusion; Hemorrhagic shock; Hipotensión; Hypotension; Massive transfusion; Occult bleeding; Politrauma; Reanimación; Resuscitation; Sangrado oculto; Shock Index; Shock hemorrágico; Transfusión masiva; Transfusión sanguínea; Trauma.