Shock Index Applications in Trauma Assessment

The Shock Index (SI), defined as the ratio of heart rate to systolic blood pressure, has emerged as a rapid, bedside tool for early identification of hypovolaemic shock in trauma patients. By integrating two universally available vital signs, SI outperforms individual parameters in predicting the need for massive transfusion, guiding haemostatic resuscitation and anticipating mortality risk. Recent extensions of the concept—such as the reverse Shock Index (rSI), which inverts the ratio to systolic blood pressure over heart rate, and composite scores that multiply rSI by the Glasgow Coma Scale (rSIG)—have refined triage accuracy, particularly in severe head injury. Across diverse settings, SI‐based approaches have demonstrated utility in resource‐limited environments, prehospital assessment and emergency department triage, enabling rapid stratification of patients who may require blood products or advanced interventions. The global uptake of SI reflects its simplicity, reproducibility and the pressing need for early indicators of shock in polytrauma and isolated head injury alike.

Research from Nature Portfolio

A recent multicentre study applied the rSIG score—calculated as (systolic blood pressure ÷ heart rate) × Glasgow Coma Scale—to adults with severe trauma and head injury. In over 400 patients, an rSIG threshold of ≤14 identified those at seven‐fold increased risk of in‐hospital mortality and achieved an area under the curve exceeding 0.75. This work highlights the added prognostic value of integrating neurological status with haemodynamic indices, facilitating prompt recognition of high‐risk patients upon arrival. No further articles meeting the criteria were identified.

Shock Index Applications in Trauma Assessment publication trend

The graph below shows the total number of articles in shock index applications in trauma assessment across all publications each year (not limited to Nature Index journals).

Technical terms

Shock Index (SI): Ratio of heart rate (beats per minute) to systolic blood pressure (mmHg), used to gauge haemodynamic compromise.

Reverse Shock Index (rSI): Inverse of SI (systolic blood pressure divided by heart rate), employed to flag deterioration when below 1.

rSIG: Composite score multiplying rSI by the Glasgow Coma Scale, combining haemodynamic and neurological assessment.

Massive transfusion: Requirement for ten or more units of red blood cells within the initial phase of resuscitation, indicating severe bleeding.

References

1. Shock index as predictor of massive transfusion and mortality in patients with trauma: a systematic review and meta-analysis. Critical Care (2023).
2. The Shock Index revisited – a fast guide to transfusion requirement? A retrospective analysis on 21,853 patients derived from the TraumaRegister DGU®. Critical Care (2013).
3. Reverse shock index multiplied by Glasgow Coma Scale (rSIG) predicts mortality in severe trauma patients with head injury. Scientific Reports (2020).