Calculate the shock index (HR ÷ systolic BP), the modified shock index and the age shock index to spot hidden hemodynamic instability early.
About this tool
Shock index, modified shock index and age shock index.
How to use Shock Index Calculator
- Enter heart rate and systolic blood pressure.
- Add diastolic pressure and age for the modified and age indices.
- Read the indices and their interpretation.
Worked example
A heart rate of 110 with a systolic pressure of 95 mmHg gives a shock index of 1.16, which is abnormal.
What is a normal shock index?
About 0.5–0.7. Values of 1.0 or more are linked to more transfusion, ICU admission and death in trauma and sepsis.
Why use it when vital signs look normal?
Heart rate rises before blood pressure falls, so the ratio can show early shock while each value alone looks acceptable.
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