Development and validation of a pre-hospital "Red Flag" alert for activation of intra-hospital haemorrhage control response in blunt trauma

Crit Care. 2018 May 5;22(1):113. doi: 10.1186/s13054-018-2026-9.


Background: Haemorrhagic shock is the leading cause of early preventable death in severe trauma. Delayed treatment is a recognized prognostic factor that can be prevented by efficient organization of care. This study aimed to develop and validate Red Flag, a binary alert identifying blunt trauma patients with high risk of severe haemorrhage (SH), to be used by the pre-hospital trauma team in order to trigger an adequate intra-hospital standardized haemorrhage control response: massive transfusion protocol and/or immediate haemostatic procedures.

Methods: A multicentre retrospective study of prospectively collected data from a trauma registry (Traumabase®) was performed. SH was defined as: packed red blood cell (RBC) transfusion in the trauma room, or transfusion ≥ 4 RBC in the first 6 h, or lactate ≥ 5 mmol/L, or immediate haemostatic surgery, or interventional radiology and/or death of haemorrhagic shock. Pre-hospital characteristics were selected using a multiple logistic regression model in a derivation cohort to develop a Red Flag binary alert whose performances were confirmed in a validation cohort.

Results: Among the 3675 patients of the derivation cohort, 672 (18%) had SH. The final prediction model included five pre-hospital variables: Shock Index ≥ 1, mean arterial blood pressure ≤ 70 mmHg, point of care haemoglobin ≤ 13 g/dl, unstable pelvis and pre-hospital intubation. The Red Flag alert was triggered by the presence of any combination of at least two criteria. Its predictive performances were sensitivity 75% (72-79%), specificity 79% (77-80%) and area under the receiver operating characteristic curve 0.83 (0.81-0.84) in the derivation cohort, and were not significantly different in the independent validation cohort of 2999 patients.

Conclusion: The Red Flag alert developed and validated in this study has high performance to accurately predict or exclude SH.

Keywords: Anticipation; Organization; Protocol; Severe haemorrhage; Severe trauma.

Publication types

  • Multicenter Study

MeSH terms

  • Adult
  • Blood Transfusion / methods
  • Blood Transfusion / statistics & numerical data
  • Chi-Square Distribution
  • Cohort Studies
  • Emergency Medical Services / methods*
  • Female
  • Hemorrhage / diagnosis*
  • Hemorrhage / physiopathology
  • Hemorrhage / surgery
  • Humans
  • Injury Severity Score
  • Lactic Acid / analysis
  • Lactic Acid / blood
  • Male
  • Middle Aged
  • Paris
  • Prospective Studies
  • ROC Curve
  • Registries / statistics & numerical data
  • Retrospective Studies
  • Simplified Acute Physiology Score
  • Statistics, Nonparametric
  • Wounds, Nonpenetrating / diagnosis*
  • Wounds, Nonpenetrating / surgery


  • Lactic Acid