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Shock Index Calculator

Input

bpm
mmHg

Shock Index

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About

The Shock Index (SI) is a simple bedside calculation defined as the ratio of heart rate to systolic blood pressure. It is used as an early indicator of hemodynamic instability and occult shock, particularly in trauma, hemorrhage, and sepsis. A normal SI is 0.5–0.7. An elevated SI may identify patients at risk before traditional vital sign thresholds are breached.

Formula

Shock Index (SI) = Heart Rate / Systolic Blood Pressure

Interpretation

Shock IndexInterpretation
0.5 – 0.7Normal
0.7 – 1.0Elevated — concern for early shock
> 1.0Significant shock
> 1.5Severe shock

References

  1. Allgöwer M, Burri C. Schockindex. Dtsch Med Wochenschr. 1967;92(43):1947-1950.
  2. Mutschler M, et al. Renaissance of the shock index as a predictor for outcome in patients with polytrauma. J Trauma Acute Care Surg. 2013;74(4):1009-1015.

FAQ

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Disclaimer

For educational and informational purposes only. Not intended to replace professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare professional.