- The Shock Index has been mostly investigated as a tool to identify patients at increased risk for transfusion in the setting of hemorrhage and trauma.
- The use of the Shock Index has also been proposed in the setting of endotracheal intubation to help identify groups of patients at risk of post-intubation hypotension.
- The Protocol-Based Care for Early Septic Shock (ProCESS) trial used the Shock Index to guide fluid administration in one of its intervention groups. It failed however to demonstrate a mortality improvement.
- A large retrospective single-center study found the Shock Index to be as sensitive as the SIRS criteria to identify patients at risk for Sepsis.
- Blood pressure and heart rate are unreliable determinants of hypovolemic shock.
- The Shock Index has been proposed as a reliable and easy to use tool for the early identification of hypovolemic shock, and the need for intervention, in a number of settings.
- There are currently no well designed, prospective studies that validate the use of the Shock Index to guide resuscitative interventions.
- Blood pressure and heart rate, when used individually, fail to accurately predict the severity of hypovolemia and shock in major trauma.
- Massive transfusion of blood products can be associated with significant risk if initiated on the wrong patient. Identifying patients at risk for massive transfusion can be difficult however, and a number of clinical decision scores such as the Shock Index are being investigated.
- Current scores such as the Assessment of Blood Consumption score have shown promising results but still need to be validated prospectively.
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- The accuracy of the Shock Index in identifying trauma patients in need of massive blood transfusion has not yet been prospectively investigated.
- No recommendations on the use of the Shock Index in the clinical setting can be made at this time and further studies are needed.
Shock Index = HR/SBP
- A retrospective study performed at a single level I trauma center identified 2,445 patients admitted over a 5 year period. Patients with an SI > 0.9 were found to have a significantly higher mortality (15.9%) when compared with patients with a normal SI (6.3%)
- In this retrospective registry study, the authors identified 8,111 blunt trauma patients admitted at a single level I trauma center over an 8 year period. The shock index was calculated from prehospital vital signs. Patients with a SI > 0.9 were found to have a 1.6-fold higher risk for massive transfusion.
- In another retrospective registry study, 21,853 patients were identified. The SI was calculated based on emergency department arrival vital signs. The degree of shock was found to correlate with increasing SI value. The need for blood products, fluids and vasopressors was also found to increase with higher SI values.
- This retrospective study of 542 patients who underwent emergency intubation identified a pre-intubation SI ≥ 9 to be independently associated with peri-intubation cardiac arrest.
- A retrospective study of 2,524 patients that were screened for severe sepsis at a single center found that SI ≥ 0.7 performed as well as SIRS in NPV and was the most sensitive screening test for hyperlactatemia and 28-day mortality.
- The ProCESS trial was a large, multicenter, prospective randomized control trial that enrolled 1,341 patients. The aim of this study was to compare different protocols of resuscitation of septic patients. One of these protocols included SI ≥ 8 as a fluid resuscitation goal. There was no significant difference in mortality between the three intervention groups.
Original/Primary ReferenceAllgöwer M, Burri C. The “shock-index”. Dtsch med Wochenschr 1967; 92(43): 1947-1950. DOI: 10.1055/s-0028-1106070
ValidationMutschler M, Nienaber U, et al. 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, 17:R172 doi:10.1186/cc12851Cannon CM, Braxton CC, Kling-Smith M, Mahnken JD, Carlton E, Moncure M. Utility of the Shock Index in Predicting Mortality in Traumatically Injured Patients. J Trauma. 2009;67(6):1426–1430.Vandromme MJ, Griffin RL, Kerby JD, McGwin G Jr., Rue LW III, Weinberg JA. Identifying Risk for Massive Transfusion in the Relatively Normotensive Patient: Utility of the Prehospital Shock Index. J Trauma. 2011;70(2):384–390.
Other ReferencesHeffner AC, Swords DS, Neale MN, Jones AE. Incidence and factors associated with cardiac arrest complicating emergency airway management. Resuscitation. 2013;84(11):1500–1504.Berger T, Green J, Horeczko T, et al. Shock Index and Early Recognition of Sepsis in the Emergency Department: Pilot Study. WestJEM. 2013;14(2):168–174.ProCESS Investigators, Yealy DM, Kellum JA, et al. A randomized trial of protocol-based care for early septic shock. N Engl J Med. 2014;370(18):1683–1693.
About the Creator
Manuel Mutschler, MD, is a practicing physician in the Department of Trauma and Orthopedic Surgery at the Cologne-Merheim Medical Center, affiliated with University of Witten/Herdecke. He is an active researcher with interests including hypovolaemic and hemorrhagic shock.
To view Dr. Manuel Mutschler's publications, visit PubMed