Shock Index

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Simple measure of hemodynamic stability and occult shock risk.

Hemodynamic Vitals

Heart Rate

bpm

Systolic Blood Pressure

mmHg

Hemodynamic Status

Shock Index0.67

StatusNormal

Physiological status appears stable.

Clinical Impression

Cut-off Values

0.5 - 0.7Normal

0.9 - 1.2Elevated

≥ 1.3Emergency Status

About this calculator

Overview

The Shock Index (SI) is a simple, non-invasive clinical tool calculated by dividing the heart rate by the systolic blood pressure. It is used to identify patients who may be in 'occult' or 'compensated' shock—where their vital signs might individually fall within the normal range, but their physiology is stressed.

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Pro Tips

Monitor for a rising trend in the Shock Index, which can indicate ongoing bleeding or worsening sepsis.
Keep in mind that beta-blockers or other medications can mask a high heart rate, potentially lowering the SI.
A high SI and a low SBP (hypotension) is a sign of decompensated shock requiring immediate resuscitation.

Fun Facts

"A normal shock index ranges between 0.5 and 0.7."
"An index > 0.9 is associated with increased mortality and the need for massive transfusion in trauma."
"It is particularly useful for identifying early hemorrhage before the development of hypotension."
"The Shock Index can be adjusted for age (Age-SI) or modified using mean arterial pressure (MSI)."

Formula: Shock Index = Heart Rate (bpm) / Systolic Blood Pressure (mmHg).