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The Shock Index revisited – a fast guide to transfusion requirement? A retrospective analysis on 21,853 patients derived from the TraumaRegister DGU®

Manuel Mutschler12*, Ulrike Nienaber3, Matthias Münzberg4, Christoph Wölfl4, Herbert Schoechl56, Thomas Paffrath1, Bertil Bouillon1, Marc Maegele1 and The TraumaRegister DGU®7

Author Affiliations

1 Department of Trauma and Orthopedic Surgery, Cologne-Merheim Medical Center, University of Witten/Herdecke, Ostmerheimerstr 200, D-51109 Cologne, Germany

2 Institute for Research in Operative Medicine, University of Witten/Herdecke, Ostmerheimerstr 200, D-51109 Cologne, Germany

3 Academy for Trauma Surgery, Luisenstr 58/59, D-10117 Berlin, Germany

4 Department of Trauma and Orthopedic Surgery, BG Hospital Ludwigshafen, Ludwig-Guttmann-Straße 13, D-67071 Ludwigshafen, Germany

5 Department of Anaesthesiology and Intensive Care, AUVA Trauma Hospital, Salzburg, Austria

6 Ludwig Boltzmann Institute for Experimental and Clinical Traumatology, Vienna, Austria

7 Committee of Emergency Medicine, Intensive Care and Trauma Management of the DGU (Section NIS), Berlin, Germany

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Critical Care 2013, 17:R172  doi:10.1186/cc12851

Published: 12 August 2013

Abstract

Introduction

Isolated vital signs (for example, heart rate or systolic blood pressure) have been shown unreliable in the assessment of hypovolemic shock. In contrast, the Shock Index (SI), defined by the ratio of heart rate to systolic blood pressure, has been advocated to better risk-stratify patients for increased transfusion requirements and early mortality. Recently, our group has developed a novel and clinical reliable classification of hypovolemic shock based upon four classes of worsening base deficit (BD). The objective of this study was to correlate this classification to corresponding strata of SI for the rapid assessment of trauma patients in the absence of laboratory parameters.

Methods

Between 2002 and 2011, data for 21,853 adult trauma patients were retrieved from the TraumaRegister DGU® database and divided into four strata of worsening SI at emergency department arrival (group I, SI <0.6; group II, SI ≥0.6 to <1.0; group III, SI ≥1.0 to <1.4; and group IV, SI ≥1.4) and were assessed for demographics, injury characteristics, transfusion requirements, fluid resuscitation and outcomes. The four strata of worsening SI were compared with our recently suggested BD-based classification of hypovolemic shock.

Results

Worsening of SI was associated with increasing injury severity scores from 19.3 (± 12) in group I to 37.3 (± 16.8) in group IV, while mortality increased from 10.9% to 39.8%. Increments in SI paralleled increasing fluid resuscitation, vasopressor use and decreasing hemoglobin, platelet counts and Quick’s values. The number of blood units transfused increased from 1.0 (± 4.8) in group I to 21.4 (± 26.2) in group IV patients. Of patients, 31% in group III and 57% in group IV required ≥10 blood units until ICU admission. The four strata of SI discriminated transfusion requirements and massive transfusion rates equally with our recently introduced BD-based classification of hypovolemic shock.

Conclusion

SI upon emergency department arrival may be considered a clinical indicator of hypovolemic shock in respect to transfusion requirements, hemostatic resuscitation and mortality. The four SI groups have been shown to equal our recently suggested BD-based classification. In daily clinical practice, SI may be used to assess the presence of hypovolemic shock if point-of-care testing technology is not available.

Keywords:
Trauma; Shock; Classification; Vital signs; Shock index; Base deficit; Transfusion