Shock index
Heart rate ÷ systolic blood pressure — bedside marker of hypovolaemic shock
- European trauma bleeding guideline 2023
Sources last checked: 2026-10-13
Shock index
Heart rate ÷ systolic blood pressure — bedside marker of hypovolaemic shock
Beta-blockers, calcium-channel blockers, pacemakers, pain, anxiety and pregnancy alter the ratio. The bands above come from adult trauma data; in children age-adjusted thresholds apply. A normal value does not exclude occult bleeding.
Interpretation
| < 0.7 — usual range | Healthy adults typically lie between 0.5 and 0.7 (European trauma bleeding guideline 2023). |
|---|---|
| 0.7–0.99 — raised | Above the usual range. In bleeding trauma patients, values of ≥ 0.8–1.0 are associated with increasing need for massive transfusion. |
| 1.0–1.39 — moderate shock | Group III in the TraumaRegister DGU analysis (Mutschler 2013): mortality 22.9 %, ≥ 10 blood units needed by 31 % before ICU admission. |
| ≥ 1.4 — severe shock | Group IV (Mutschler 2013): mortality 39.8 %, ≥ 10 blood units needed by 57 % before ICU admission. |
What is the Shock index?
The shock index is heart rate divided by systolic blood pressure. Allgöwer and Burri described it in 1967 in the Deutsche Medizinische Wochenschrift as a simple marker of circulatory compromise. A large analysis of the German TraumaRegister DGU (Mutschler 2013) linked four shock-index strata to transfusion needs and mortality, and the European trauma bleeding guideline 2023 recommends its use.
When to use it
- Rapid assessment of hypovolaemic or haemorrhagic shock in trauma patients.
- Early recognition of haemodynamic compromise when blood pressure is still 'normal'.
- Pre-hospital and emergency-department triage, including for massive-transfusion activation.
When not to use it
- Patients on beta-blockers or with pacemakers, where heart rate cannot rise.
- Children without age-adjusted thresholds.
How it is calculated
Shock index = heart rate (/min) ÷ systolic blood pressure (mmHg)
Clinical pearls and limitations
- Beta-blockers, calcium-channel blockers, pacemakers, pain, anxiety and pregnancy alter the ratio. The bands above come from adult trauma data; in children age-adjusted thresholds apply. A normal value does not exclude occult bleeding.
- Normal adult values are about 0.5–0.7.
- The trend is informative: a rising value despite stable blood pressure suggests ongoing bleeding.
- European guideline 2023 recommends shock index and/or pulse pressure to assess hypovolaemic shock and transfusion needs.
- Variants include the modified shock index (heart rate ÷ MAP) and age × shock index.
Frequently asked questions
What is a normal shock index?
About 0.5 to 0.7 in healthy adults.
What shock index indicates shock?
Values of 1.0 or above indicate shock in trauma data; in the TraumaRegister DGU analysis ≥ 1.4 identified severe shock with high transfusion needs.
How do I calculate the shock index?
Divide heart rate (beats per minute) by systolic blood pressure (mmHg), e.g. 110 ÷ 100 = 1.1.
Evidence and guidelines
- Primary source: Allgöwer M, Burri C. „Schockindex“. Dtsch Med Wochenschr 1967;92(43):1947-1950.
- Mutschler M, Nienaber U, Münzberg M et al. The Shock Index revisited – a fast guide to transfusion requirement? A retrospective analysis on 21,853 patients derived from the TraumaRegister DGU. Crit Care 2013;17(4):R172.
- Rossaint R et al. The European guideline on management of major bleeding and coagulopathy following trauma: sixth edition. Crit Care 2023;27:80 — recommendation 5.
- Koch E, Lovett S, Nghiem T, Riggs RA, Rech MA. Shock index in the emergency department: utility and limitations. Open Access Emerg Med 2019;11:179-199.
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