Shock Index

Simple ratio of heart rate to systolic blood pressure. Elevated values suggest occult shock or circulatory compromise.

bpm

Heart rate in beats per minute

mmHg

Systolic blood pressure in mmHg

Enter heart rate and systolic BP to calculate shock index

References

  1. Shock index - Medscape - Medscape
  2. Shock Index and Modified Shock Index - Journal of Clinical Medicine

Clinical Notes & Warnings

  • SI >0.9 is associated with increased mortality in trauma, MI, sepsis.
  • SI >1.0 suggests hemodynamic compromise even if BP is maintained.
  • Elderly patients may have falsely reassuring BP with elevated SI.
  • Modified Shock Index = HR / (SBP * age factor) for age-specific thresholds.

SI is more sensitive than BP alone for detecting occult shock. AHRQ recommends 0.9 as threshold for prompt evaluation.